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Chapter 1. Configuring OSPF

Finding Feature Information

Information About OSPF

Cisco OSPF Implementation

Router Coordination for OSPF

Route Distribution for OSPF

OSPF Network Types

Original LSA Behavior

LSA Group Pacing with Multiple Timers

Restrictions for OSPF

How to Configure OSPF

Enabling OSPF

Configuring OSPF Interface Parameters

Configuring OSPFv2 NSSA

Configuring an OSPFv2 NSSA Area and Its Parameters

Configuring an NSSA ABR as a Forced NSSA LSA Translator

Disabling RFC 3101 Compatibility and Enabling RFC 1587 Compatibility

Configuring OSPF over Different Physical Networks

Configuring OSPF for Point-to-Multipoint Broadcast Networks

Configuring OSPF for Nonbroadcast Networks

Configuring OSPF Area Parameters

Configuring OSPF NSSA Parameters

Prerequisites

Configuring OSPF NSSA Area Parameters

Configuring Route Summarization Between OSPF Areas

Configuring Route Summarization When Redistributing Routes into OSPF

Establishing Virtual Links

Generating a Default Route

Configuring Lookup of DNS Names

Forcing the Router ID Choice with a Loopback Interface

Controlling Default Metrics

Changing the OSPF Administrative Distances

Configuring OSPF on Simplex Ethernet Interfaces

Configuring Route Calculation Timers

Configuring OSPF over On-Demand Circuits

Prerequisites

Logging Neighbors Going Up or Down

Changing the LSA Group Pacing Interval

Blocking OSPF LSA Flooding

Reducing LSA Flooding

Ignoring MOSPF LSA Packets

Displaying OSPF Update Packet Pacing

Monitoring and Maintaining OSPF

Configuration Examples for OSPF

Example: OSPF Point-to-Multipoint

Example: OSPF Point-to-Multipoint with Broadcast

Example: OSPF Point-to-Multipoint with Nonbroadcast

Example: Variable-Length Subnet Masks

Example: Configuring OSPF NSSA

Example: OSPF NSSA Area with RFC 3101 Disabled and RFC 1587 Active

Example: OSPF Routing and Route Redistribution

Example: Basic OSPF Configuration

Example: Basic OSPF Configuration for Internal Router ABR and ASBRs

Example: Complex Internal Router with ABR and ASBR

Example: Complex OSPF Configuration for ABR

Examples: Route Map

Example: Changing the OSPF Administrative Distances

Example: OSPF over On-Demand Routing

Example: LSA Group Pacing

Example: Blocking OSPF LSA Flooding

Example: Ignoring MOSPF LSA Packets

Additional References for OSPF Not-So-Stubby Areas (NSSA)

Feature Information for Configuring OSPF

Chapter 2. IPv6 Routing: OSPFv3

Finding Feature Information

Prerequisites for IPv6 Routing: OSPFv3

Restrictions for IPv6 Routing: OSPFv3

Information About IPv6 Routing: OSPFv3

How OSPFv3 Works

Comparison of OSPFv3 and OSPF Version 2

LSA Types for OSPFv3

NBMA in OSPFv3

Load Balancing in OSPFv3

Addresses Imported into OSPFv3

OSPFv3 Customization

OSPFv3 Cost Calculation

Force SPF in OSPFv3

How to Configure Load Balancing in OSPFv3

Configuring the OSPFv3 Device Process

Configuring NBMA Interfaces in OSPFv3

Forcing an SPF Calculation

Verifying OSPFv3 Configuration and Operation

Configuration Examples for Load Balancing in OSPFv3

Example: Configuring the OSPFv3 Device Process

Example: Configuring NBMA Interfaces

Example: Forcing SPF Configuration

Additional References

Feature Information for IPv6 Routing: OSPFv3

Chapter 3. IPv6 Routing: OSPFv3 Authentication Support with IPsec

Finding Feature Information

Prerequisites for IPv6 Routing: OSPFv3 Authentication Support with IPsec

Information About IPv6 Routing: OSPFv3 Authentication Support with IPsec

OSPFv3 Authentication Support with IPsec

How to Configure IPv6 Routing: OSPFv3 Authentication Support with IPsec

Configuring IPsec on OSPFv3

Defining Authentication on an Interface

Defining Authentication in an OSPFv3 Area

Configuration Examples for IPv6 Routing: OSPFv3 Authentication Support with IPsec

Example: Defining Authentication on an Interface

Example: Defining Authentication in an OSPFv3 Area

Additional References for IPv6 Routing: OSPFv3 Authentication Support with IPsec

Feature Information for IPv6 Routing: OSPFv3 Authentication Support with IPsec

Chapter 4. OSPFv2 Cryptographic Authentication

Finding Feature Information

Prerequisites for OSPFv2 Cryptographic Authentication

Information About OSPFv2 Cryptographic Authentication

Configuring OSPFv2 Cryptographic Authentication

How to Configure OSPFv2 Cryptographic Authentication

Defining a Key Chain

Defining Authentication on an Interface

Configuration Examples for OSPFv2 Cryptographic Authentication

Example: Defining a Key Chain

Example: Verifying a Key Chain

Example: Defining Authentication on an Interface

Example: Verifying Authentication on an Interface

Additional References for OSPFv2 Cryptographic Authentication

Feature Information for OSPFv2 Cryptographic Authentication

Chapter 5. OSPFv3 IPSec ESP Encryption and Authentication

Finding Feature Information

Prerequisites for OSPFv3 IPSec ESP Encryption and Authentication

Information About OSPFv3 IPSec ESP Encryption and Authentication

OSPFv3 Authentication Support with IPsec

OSPFv3 Virtual Links

How to Configure OSPFv3 IPSec ESP Encryption and Authentication

Defining Encryption on an Interface

Defining Encryption in an OSPFv3 Area

Defining Authentication and Encryption for a Virtual Link in an OSPFv3 Area

Configuration Examples for OSPFv3 IPSec ESP Encryption and Authentication

Example: Defining Encryption in an OSPFv3 Area

Additional References

Feature Information for OSPFv3 IPSec ESP Encryption and Authentication

Chapter 6. OSPF ABR Type 3 LSA Filtering

Finding Feature Information

Benefits

Restrictions

Related Features and Technologies

Configuration Tasks

Configuring OSPF ABR Type 3 LSA Filtering

Configuring OSPF ABR Type 3 LSA Filtering

Verifying OSPF ABR Type 3 LSA Filtering

Monitoring and Maintaining OSPF ABR Type 3 LSA Filtering

Configuration Examples

Additional References

Feature Information for the OSPF ABR Type 3 LSA Filtering

Chapter 7. OSPF Stub Router Advertisement

Finding Feature Information

Information About OSPF Stub Router Advertisement

OSPF Stub Router Advertisement Functionality

Allowing Routing Tables to Converge

Configuring a Graceful Shutdown

Benefits of OSPF Stub Router Advertisement

Related Features and Technologies

Supported Platforms

How to Configure OSPF Stub Router Advertisement

Configuring Advertisement on Startup

Configuring Advertisement Until Routing Tables Converge

Configuring Advertisement for a Graceful Shutdown

Verifying the Advertisement of a Maximum Metric

Monitoring and Maintaining OSPF Stub Router Advertisement

Configuration Examples of OSPF Stub Router Advertisement

Example Advertisement on Startup

Example Advertisement Until Routing Tables Converge

Example Graceful Shutdown

Additional References

Feature Information for OSPF Stub Router Advertisement

Chapter 8. OSPF Update Packet-Pacing Configurable Timers

Finding Feature Information

Restrictions on OSPF Update Packet-Pacing Configurable Timers

Information About OSPF Update Packet-Pacing Configurable Timers

Functionality of the OSPF Update Packet-Pacing Timers

Benefits of OSPF Update Packet-Pacing Configurable Timers

Related Features and Technologies

Supported Platforms

How to Configure OSPF Packet-Pacing Timers

Configuring OSPF Packet-Pacing Timers

Configuring a Group Packet Pacing Timer

Configuring a Group Packet Pacing Timer

Verifying OSPF Packet-Pacing Timers

Troubleshooting Tips

Monitoring and Maintaining OSPF Packet-Pacing Timers

Configuration Examples of OSPF Update Packet-Pacing

Example Flood Pacing

Example Retransmission Pacing

Example Group Pacing

Additional References

Feature Information for OSPF Update Packet-Pacing Configurable Timers

Chapter 9. OSPF Sham-Link Support for MPLS VPN

Finding Feature Information

Feature Overview

Using OSPF in PE-CE Router Connections

Using a Sham-Link to Correct OSPF Backdoor Routing

Sham-Link Configuration Example

Benefits

Restrictions

Related Features and Technologies

Related Documents

Supported Platforms

Supported Standards MIBs and RFCs

Prerequisites

Configuration Tasks

Creating a Sham-Link

Verifying Sham-Link Creation

Monitoring and Maintaining a Sham-Link

Configuration Examples

Glossary

Chapter 10. OSPF Retransmissions Limit

Finding Feature Information

Restrictions For OSPF Retransmissions Limit

Information About OSPF Retransmissions Limit

Overview About OSPF Retransmissions Limit

Benefits

How to Configure OSPF Retransmissions Limit

Setting OSPF Retransmission Limits

Configuration Examples for OSPF Retransmissions Limit

Example: Configuring OSPF Retransmissions Limit

Additional References for OSPF Retransmissions Limit

Feature Information for OSPF Retransmissions Limit

Chapter 11. OSPF Support for Multi-VRF on CE Routers

Finding Feature Information

Information About OSPF Support for Multi-VRF on CE Routers

How to Configure OSPF Support for Multi-VRF on CE Routers

Configuring the Multi-VRF Capability for OSPF Routing

Verifying the OSPF Multi-VRF Configuration

Configuration Examples for OSPF Support for Multi-VRF on CE Routers

Example Configuring the Multi-VRF Capability

Example Verifying the OSPF Multi-VRF Configuration

Additional References

Feature Information for OSPF Support for Multi-VRF on CE Routers

Glossary

Chapter 12. OSPFv2 Multiarea Adjacency

Finding Feature Information

Prerequisites for OSPFv2 Multiarea Adjacency

Restrictions for OSPFv2 Multiarea Adjacency

Information About OSPFv2 Multiarea Adjacency

OSPFv2 Multiarea Adjacency Overview

How to Configure OSPFv2 Multiarea Adjacency

Configuring OSPFv2 Multiarea Adjacency

Configuration Examples for OSPFv2 Multiarea Adjacency

Example: Configuring OSPFv2 Multiarea Adjacency

Additional References for OSPFv2 Multiarea Adjacency

Feature Information for OSPFv2 Multiarea Adjacency

Chapter 13. OSPFv2 Autoroute Exclude

Finding Feature Information

Prerequisites for OSPFv2 Autoroute Exclude

Information About OSPFv2 Autoroute Exclude

Overview of OSPFv2 Autoroute Exclude

How to Configure OSPFv2 Autoroute Exclude

Configuring OSPFv2 Autoroute Exclude

Configuration Examples for OSPFv2 Autoroute Exclude

Example: Configuring OSPFv2 Autoroute Exclude

Additional References for OSPFv2 Autoroute Exclude

Feature Information for OSPFv2 Autoroute Exclude

Chapter 14. OSPFv3 Multiarea Adjacency

Finding Feature Information

Prerequisites for OSPFv3 Multiarea Adjacency

Restrictions for OSPFv3 Multiarea Adjacency

Information About OSPFv3 Multiarea Adjacency

OSPFv3 Multiarea Adjacency Overview

How to Configure OSPFv3 Multiarea Adjacency

Configuring OSPFv3 Multiarea Adjacency

Verifying OSPFv3 Multiarea Adjacency

Configuration Examples for OSPFv3 Multiarea Adjacency

Example: OSPFv3 Multiarea Adjacency Configuration

Example: Verifying OSPFv3 Multiarea Adjacency

Additional References for OSPFv3 Multiarea Adjacency

Feature Information for OSPFv3 Multiarea Adjacency

Chapter 15. OSPFv3 Authentication Trailer

Finding Feature Information

Information About OSPFv3 Authentication Trailer

Overview of OSPFv3 Authentication Trailer

How to Configure OSPFv3 Authentication Trailer

Configuring OSPFv3 Authentication Trailer

Configuration Examples for OSPFv3 Authentication Trailer

Example: Configuring OSPFv3 Authentication Trailer

Example: Verifying OSPFv3 Authentication Trailer

Additional References for OSPFv3 Authentication Trailer

Feature Information for OSPFv3 Authentication Trailer

Chapter 16. OSPFv3 Autoroute Exclude

Finding Feature Information

Prerequisites for OSPFv3 Autoroute Exclude

Information About OSPFv3 Autoroute Exclude

Overview of OSPFv3 Autoroute Exclude

How to Configure OSPFv3 Autoroute Exclude

Configuring OSPFv3 Autoroute Exclude

Configuration Examples for OSPFv3 Autoroute Exclude

Example: Configuring OSPFv3 Autoroute Exclude

Additional References for OSPFv3 Autoroute Exclude

Feature Information for OSPFv3 Autoroute Exclude

Chapter 17. OSPFv2-OSPF Live-Live

Finding Feature Information

Information About OSPFv2-OSPF Live-Live

Overview of OSPFv2-OSPF Live-Live

How to Configure OSPFv2-OSPF Live-Live

Configuring OSPFv2-OSPF Live-Live

Configuration Examples for OSPFv2-OSPF Live-Live

Example: Configuring OSPFv2-OSPF Live-Live

Additional References for OSPFv2-OSPF Live-Live

Feature Information for OSPFv2-OSPF Live-Live

Chapter 18. OSPFv3 Address Families

Finding Feature Information

Prerequisites for OSPFv3 Address Families

Information About OSPFv3 Address Families

OSPFv3 Address Families

How to Configure OSPFv3 Address Families

Configuring the OSPFv3 Device Process

Configuring the IPv6 Address Family in OSPFv3

Configuring the IPv4 Address Family in OSPFv3

Configuring Route Redistribution in OSPFv3

Enabling OSPFv3 on an Interface

Defining an OSPFv3 Area Range for the IPv6 or IPv4 Address Family

Defining an OSPFv3 Area Range

Configuration Examples for OSPFv3 Address Families

Example: Configuring OSPFv3 Address Families

Additional References

Feature Information for OSPFv3 Address Families

Chapter 19. OSPF Forwarding Address Suppression in Translated Type-5 LSAs

Finding Feature Information

Prerequisites for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

Information About OSPF Forwarding Address Suppression in Translated Type-5 LSAs

Benefits of OSPF Forwarding Address Suppression in Translated Type-5 LSAs

When to Suppress OSPF Forwarding Address in Translated Type-5 LSAs

How to Suppress OSPF Forwarding Address in Translated Type-5 LSAs

Suppressing OSPF Forwarding Address in Translated Type-5 LSAs

Configuration Examples for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

Example Suppressing OSPF Forwarding Address in Translated Type-5 LSAs

Additional References

Feature Information for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

Chapter 20. OSPF Inbound Filtering Using Route Maps with a Distribute List

Finding Feature Information

Prerequisites for OSPF Inbound Filtering Using Route Maps with a Distribute List

Information About OSPF Inbound Filtering Using Route Maps with a Distribute List

How to Configure OSPF Inbound Filtering Using Route Maps

Configuring OSPF Route Map-Based Filtering

Configuration Examples for OSPF Inbound Filtering Using Route Maps with a Distribute List

Example OSPF Route Map-Based Filtering

Additional References

Feature Information for OSPF Inbound Filtering Using Route Maps with a Distribute List

Chapter 21. OSPFv3 Fast Convergence: LSA and SPF Throttling

Finding Feature Information

Information About OSPFv3 Fast Convergence: LSA and SPF Throttling

Fast Convergence: LSA and SPF Throttling

How to Configure OSPFv3 Fast Convergence: LSA and SPF Throttling

Tuning LSA and SPF Timers for OSPFv3 Fast Convergence

Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

Configuration Examples for OSPFv3 Fast Convergence: LSA and SPF Throttling

Example: Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

Additional References

Feature Information for OSPFv3 Fast Convergence: LSA and SPF Throttling

Chapter 22. OSPF Shortest Path First Throttling

Finding Feature Information

Information About OSPF SPF Throttling

Shortest Path First Calculations

How to Configure OSPF SPF Throttling

Configuring OSPF SPF Throttling

Verifying SPF Throttle Values

Configuration Examples for OSPF SPF Throttling

Throttle Timers Example

Additional References

Chapter 23. OSPF Support for Fast Hello Packets

Finding Feature Information

Prerequisites for OSPF Support for Fast Hello Packets

Information About OSPF Support for Fast Hello Packets

OSPF Hello Interval and Dead Interval

OSPF Fast Hello Packets

Benefits of OSPF Fast Hello Packets

How to Configure OSPF Fast Hello Packets

Configuring OSPF Fast Hello Packets

Configuration Examples for OSPF Support for Fast Hello Packets

Example OSPF Fast Hello Packets

Additional References

Feature Information for OSPF Support for Fast Hello Packets

Chapter 24. OSPF Incremental SPF

Finding Feature Information

Prerequisites for OSPF Incremental SPF

Information About OSPF Incremental SPF

How to Enable OSPF Incremental SPF

Enabling Incremental SPF

Configuration Examples for OSPF Incremental SPF

Example Incremental SPF

Additional References

Feature Information for OSPF Incremental SPF

Chapter 25. OSPF Limit on Number of Redistributed Routes

Finding Feature Information

Prerequisites for OSPF Limit on Number of Redistributed Routes

Information About OSPF Limit on Number of Redistributed Routes

How to Configure OSPF Limit the Number of OSPF Redistributed Routes

Limiting the Number of OSPF Redistributed Routes

Requesting a Warning About the Number of Routes Redistributed into OSPF

Configuration Examples for OSPF Limit on Number of Redistributed Routes

Example OSPF Limit on Number of Redistributed Routes

Example Requesting a Warning About the Number of Redistributed Routes

Additional References

Feature Information for OSPF Limit on Number of Redistributed Routes

Chapter 26. OSPFv3 Max-Metric Router LSA

Finding Feature Information

Information About OSPFv3 Max-Metric Router LSA

OSPFv3 Max-Metric Router LSA

How to Configure OSPFv3 Max-Metric Router LSA

Configuring the OSPFv3 Max-Metric Router LSA

Configuration Examples for OSPFv3 Max-Metric Router LSA

Example: Verifying the OSPFv3 Max-Metric Router LSA

Additional References

Feature Information for OSPFv3 Max-Metric Router LSA

Chapter 27. OSPF Link-State Advertisement Throttling

Finding Feature Information

Prerequisites for OSPF LSA Throttling

Information About OSPF LSA Throttling

Benefits of OSPF LSA Throttling

How OSPF LSA Throttling Works

How to Customize OSPF LSA Throttling

Customizing OSPF LSA Throttling

Configuration Examples for OSPF LSA Throttling

Example OSPF LSA Throttling

Additional References

Chapter 28. OSPF Support for Unlimited Software VRFs per PE Router

Finding Feature Information

Prerequisites for OSPF Support for Unlimited Software VRFs per PE Router

Restrictions for OSPF Support for Unlimited Software VRFs per PE Router

Information About OSPF Support for Unlimited Software VRFs per PE Router

How to Configure OSPF Support for Unlimited Software VRFs per PE Router

Configuring and Verifying Unlimited Software VRFs per Provider Edge Router

Configuration Examples for OSPF Support for Unlimited Software VRFs per PE Router

Example Configuring OSPF Support for Unlimited Software VRFs per PE Router

Example Verifying OSPF Support for Unlimited Software VRFs per PE Router

Additional References

Glossary

Chapter 29. OSPF Area Transit Capability

Finding Feature Information

Information About OSPF Area Transit Capability

How to Disable OSPF Area Transit Capability

Disabling OSPF Area Transit Capability on an Area Border Router

Additional References

Feature Information for OSPF Area Transit Capability

Chapter 30. OSPF Per-Interface Link-Local Signaling

Finding Feature Information

Information About OSPF Per-Interface Link-Local Signaling

Benefits of the OSPF Per-Interface Link-Local Signaling Feature

How to Configure OSPF Per-Interface Link-Local Signaling

Turning Off LLS on a Per-Interface Basis

What to Do Next

Configuration Examples for OSPF Per-Interface Link-Local Signaling

Example OSPF Per-Interface Link-Local Signaling

Additional References

Feature Information for OSPF Per-Interface Link-Local Signaling

Chapter 31. OSPF Link-State Database Overload Protection

Finding Feature Information

Prerequisites for OSPF Link-State Database Overload Protection

Information About OSPF Link-State Database Overload Protection

Benefits of Using OSPF Link-State Database Overload Protection

How OSPF Link-State Database Overload Protection Works

How to Configure OSPF Link-State Database Overload Protection

Limiting the Number of NonSelf-Generating LSAs for an OSPF Process

Verifying the Number of Nonself-Generated LSAs on a Router

Configuration Examples for OSPF Link-State Database Overload Protection

Example Setting a Limit for LSA Generation

Additional References

Glossary

Chapter 32. OSPF Enhanced Traffic Statistics for OSPFv2 and OSPFv3

Finding Feature Information

Prerequisites for OSPF Enhanced Traffic Statistics

Information About OSPF Enhanced Traffic Statistics

How to Display and Clear OSPF Enhanced Traffic Statistics

Displaying and Clearing OSPF Traffic Statistics for OSPFv2

Displaying and Clearing OSPF Traffic Statistics for OSPFv3

Configuration Examples for OSPF Enhanced Traffic Commands

Displaying and Clearing Enhanced Traffic Statistics for OSPFv2 Example

Displaying and Clearing Enhanced Traffic Statistics for OSPFv3 Example

Additional References

Feature Information for OSPF Enhanced Traffic Statistics

Chapter 33. OSPF MIB Support of RFC 1850 and Latest Extensions

Finding Feature Information

Prerequisites for OSPF MIB Support of RFC 1850 and Latest Extensions

Restrictions for OSPF MIB Support of RFC 1850 and Latest Extensions

Information About OSPF MIB Support of RFC 1850 and Latest Extensions

OSPF MIB Changes to Support RFC 1850

OSPF MIB

OSPF TRAP MIB

CISCO OSPF MIB

CISCO OSPF TRAP MIB

Benefits of the OSPF MIB

How to Enable OSPF MIB Support of RFC 1850 and Latest Extensions

Enabling OSPF MIB Support

What to Do Next

Enabling Specific OSPF Traps

Verifying OSPF MIB Traps on the Router

Configuration Examples for OSPF MIB Support of RFC 1850 and Latest Extensions

Example Enabling and Verifying OSPF MIB Support Traps

Where to Go Next

Additional References

Feature Information for OSPF MIB Support of RFC 1850 and Latest Extensions

Chapter 34. SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields

Finding Feature Information

Prerequisites for Interface ID in Data Fields

Information About Interface ID in Data Fields

Benefits of Choosing to Identify Interfaces by the SNMP MIB-II ifIndex Value

How OSPFv2 and OSPFv3 Use the SNMP MIB-II ifIndex Value

How to Configure the Interface ID in Data Fields

Using SNMP MIB-II ifIndex Numbers

Configuration Examples for the Interface ID in Data Fields

Configuring the SNMP ifIndex Value for Interface ID for OSPFv2 Example

Configuring the SNMP ifIndex Value for Interface ID for OSPFv3 Example

Additional References

Feature Information for SNMP ifIndex Value for Interface ID in Data Fields

Glossary

Chapter 35. OSPFv3 Graceful Restart

Finding Feature Information

Information About OSPFv3 Graceful Restart

OSPFv3 Graceful Restart

How to Enable OSPFv3 Graceful Restart

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Device

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Device

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Device

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Device

Configuration Examples for OSPFv3 Graceful Restart

Example: Enabling OSPFv3 Graceful Restart

Additional References

Feature Information for OSPFv3 Graceful Restart

Chapter 36. OSPF RFC 3623 Graceful Restart Helper Mode

Finding Feature Information

Prerequisites for OSPF RFC 3623 Graceful Restart Helper Mode

Restrictions for OSPF RFC 3623 Graceful Restart Helper Mode

Information About OSPF RFC 3623 Graceful Restart Helper Mode

Cisco NSF Routing and Forwarding Operation

Cisco Express Forwarding for NSF

OSPF Graceful Restart Helper Mode Functionality per RFC 3623

How to Use OSPF RFC 3623 Graceful Restart Helper Mode

Configuring Strict LSA Checking on the Helper Router

Configuration Examples for OSPF RFC 3623 Graceful Restart Helper Mode

Example Disabling Helper Support for IETF NSF

Additional References

Feature Information for OSPF RFC 3623 Graceful Restart Helper Mode

Chapter 37. OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements

Finding Feature Information

Prerequisites for Excluding Connected IP Prefixes from LSAs

Information About Excluding Connected IP Prefixes from LSAs

Previous Methods to Limit the Number of IP Prefixes Carried in LSAs

Feature Overview

How to Exclude Connected IP Prefixes from OSPF LSAs

Excluding IP Prefixes per OSPF Process

Excluding IP Prefixes on a Per-Interface Basis

Troubleshooting IP Prefix Suppression

Configuration Examples for Excluding Connected IP Prefixes from LSAs

Excluding IP Prefixes from LSAs for an OSPF Process Example

Excluding IP Prefixes from LSAs for a Specified Interface Example

Additional References

Feature Information for OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements

Glossary

Chapter 38. OSPFv2 Local RIB

Finding Feature Information

Prerequisites for OSPFv2 Local RIB

Restrictions for OSPFv2 Local RIB

Information About OSPFv2 Local RIB

Function of the OSPF Local RIB

How to Configure the OSPFv2 Local RIB Feature

Changing the Default Local RIB Criteria

Changing the Administrative Distance for Discard Routes

Troubleshooting Tips

Configuration Examples for the OSPFv2 Local RIB Feature

Example: Changing the Default Local RIB Criteria

Example: Changing the Administrative Distance for Discard Routes

Additional References

Feature Information for the OSPFv2 Local RIB Feature

Chapter 39. OSPFv3 MIB

Finding Feature Information

Prerequisites for OSPFv3 MIB

Restrictions for OSPFv3 MIB Support

OSPFv3 MIB

OSPFv3 TRAP MIB

Enabling Specific OSPFv3 Traps

Verifying OSPFv3 MIB Traps on the Device

Example: Enabling and Verifying OSPFv3 MIB Traps

Additional References for OSPFv3 MIB

Feature Information for OSPFv3 MIB

Chapter 40. TTL Security Support for OSPFv3 on IPv6

Finding Feature Information

Restrictions for TTL Security Support for OSPFv3 on IPv6

Prerequisites for TTL Security Support for OSPFv3 on IPv6

Information About TTL Security Support for OSPFv3 on IPv6

OSPFv3 TTL Security Support for Virtual and Sham Links

How to Configure TTL Security Support for OSPFv3 on IPv6

Configuring TTL Security Support on Virtual Links for OSPFv3 on IPv6

Configuring TTL Security Support on Sham Links for OSPFv3 on IPv6

Configuration Examples for TTL Security Support for OSPFv3 on IPv6

Example: TTL Security Support on Virtual Links for OSPFv3 on IPv6

Example: TTL Security Support on Sham Links for OSPFv3 on IPv6

Additional References

Feature Information for TTL Security Support for OSPFv3 on IPv6

Chapter 41. OSPFv3 VRF-Lite/PE-CE

Finding Feature Information

Restrictions for OSPFv3 VRF-Lite/PE-CE

Support for OSPFv3 VRF-Lite and PE-CE

Configuring a VRF in an IPv6 Address Family for OSPFv3

Enabling an OSPFv3 IPv6 Address Family on a VRF Interface

Configuring a Sham-Link for OSPFv3 PE-CE

Configuring a Domain ID for an OSPFv3 PE-CE

Configuring VRF-Lite Capability for OSPFv3

Example: Configuring a Provider Edge Device to Provide IPv6 and IPv4 Routing

Example: Configuring a Provider Edge Device for VRF-Lite

Additional References for OSPFv3 VRF-Lite/PE-CE

Feature Information for OSPFv3 VRF-Lite/PE-CE

Chapter 42. Graceful Shutdown Support for OSPFv3

Finding Feature Information

OSPFv3 Graceful Shutdown

Configuring Graceful Shutdown of the OSPFv3 Process

Configuring Graceful Shutdown of the OSPFv3 Process in Address-Family Configuration Mode

Configuring OSPFv3 Graceful Shutdown of the OSPFv3 Interface

Example: Configuring Graceful Shutdown of the OSPFv3 Process

Example: Configuring Graceful Shutdown of the OSPFv3 Interface

Additional References for Graceful Shutdown Support for OSPFv3

Feature Information for Graceful Shutdown Support for OSPFv3

Chapter 43. Prefix Suppression Support for OSPFv3

Finding Feature Information

Prerequisites for Prefix Suppression Support for OSPFv3

OSPFv3 Prefix Suppression Support

Globally Suppress IPv4 and IPv6 Prefix Advertisements by Configuring the OSPFv3 Process

Suppress IPv4 and IPv6 Prefix Advertisements on a Per-Interface Basis

Configuring Prefix Suppression Support of the OSPFv3 Process

Configuring Prefix Suppression Support of the OSPFv3 Process in Address-Family Configuration Mode

Configuring Prefix Suppression Support on a Per-Interface Basis

Troubleshooting IPv4 and IPv6 Prefix Suppression

Example: Configuring Prefix Suppression Support for OSPFv3

Additional References for Prefix Suppression Support for OSPFv3

Feature Information for Prefix Suppression Support for OSPFv3

Chapter 44. OSPFv3 ABR Type 3 LSA Filtering

Finding Feature Information

OSPFv3 ABR Type 3 LSA Filtering

Area Filter Support

Configuring Area Filter Support for OSPFv3

Example: Area Filter Support for OSPFv3

Additional References for OSPFv3 ABR Type 3 LSA Filtering

Feature Information for OSPFv3 ABR Type 3 LSA Filtering

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Chapter 1. Configuring OSPF

This module describes how to configure Open Shortest Path First (OSPF). OSPF is an Interior Gateway Protocol (IGP) developed by the OSPF working group of the Internet Engineering Task Force (IETF). OSPF was designed expressly for IP networks and it supports IP subnetting and tagging of externally derived routing information. OSPF also allows packet authentication and uses IP multicast when sending and receiving packets.

Cisco supports RFC 1253, OSPF Version 2 Management Information Base, August 1991. The OSPF MIB defines an IP routing protocol that provides management information related to OSPF and is supported by Cisco routers.

For protocol-independent features that work with OSPF, see the "Configuring IP Routing Protocol-Independent Features" module.

- Finding Feature Information

- Information About OSPF

- Restrictions for OSPF

- How to Configure OSPF

- Configuration Examples for OSPF

- Additional References for OSPF Not-So-Stubby Areas (NSSA)

- Feature Information for Configuring OSPF

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPF

- Cisco OSPF Implementation

- Router Coordination for OSPF

- Route Distribution for OSPF

Cisco OSPF Implementation

The Cisco implementation conforms to the OSPF Version 2 specifications detailed in the Internet RFC 2328. The following list outlines key features supported in the Cisco OSPF implementation:

- Stub areas—The definition of stub areas is supported.

- Route redistribution—Routes learned via any IP routing protocol can be redistributed into any other IP routing protocol. At the intradomain level, OSPF can import routes learned via Interior Gateway Routing Protocol (IGRP), Routing Information Protocol (RIP), and Intermediate System-to-Intermediate System (IS-IS). OSPF routes can also be exported into IGRP, RIP, and IS-IS. At the interdomain level, OSPF can import routes learned via Exterior Gateway Protocol (EGP) and Border Gateway Protocol (BGP). OSPF routes can be exported into EGP and BGP.

- Authentication—Plain text and message-digest algorithm 5 (MD5) authentication among neighboring routers within an area is supported.

- Routing interface parameters—Configurable parameters supported include interface output cost, retransmission interval, interface transmit delay, router priority, router “dead” and hello intervals, and authentication key.

- Virtual links—Virtual links are supported.

- Not-so-stubby area (NSSA)—RFC 3101, which replaces and is backward compatible with RFC 1587.

- OSPF over demand circuit—RFC 1793.

Router Coordination for OSPF

OSPF typically requires coordination among many internal routers: Area Border Routers (ABRs), which are routers connected to multiple areas, and Autonomous System Boundary Routers (ASBRs). At a minimum, OSPF-based routers or access servers can be configured with all default parameter values, no authentication, and interfaces assigned to areas. If you intend to customize your environment, you must ensure coordinated configurations of all routers.

Route Distribution for OSPF

You can specify route redistribution; see the task “Redistribute Routing Information” in the Network Protocols Configuration Guide, Part 1, for information on how to configure route redistribution.

The Cisco OSPF implementation allows you to alter certain interface-specific OSPF parameters, as needed. You are not required to alter any of these parameters, but some interface parameters must be consistent across all routers in an attached network. Those parameters are controlled by the ip ospf hello-interval, ip ospf dead-interval, and ip ospf authentication-key interface configuration commands. Therefore, if you do configure any of these parameters, ensure that the configurations for all routers on your network have compatible values.

By default, OSPF classifies different media into the following three types of networks:

- Broadcast networks (Ethernet, Token Ring, and FDDI)

- Nonbroadcast multiaccess (NBMA) networks (Switched Multimegabit Data Service [SMDS], Frame Relay, and X.25)

- Point-to-point networks (High-Level Data Link Control [HDLC] and PPP)

You can configure your network as either a broadcast or an NBMA network.

X.25 and Frame Relay provide an optional broadcast capability that can be configured in the map to allow OSPF to run as a broadcast network. See the x25 map and frame-relay map command pages in the Cisco IOS Wide-Area Networking Command Reference publication for more detail.

- OSPF Network Types

- Original LSA Behavior

- LSA Group Pacing with Multiple Timers

OSPF Network Types

You have the choice of configuring your OSPF network type as either broadcast or NBMA, regardless of the default media type. Using this feature, you can configure broadcast networks as NBMA networks when, for example, you have routers in your network that do not support multicast addressing. You also can configure NBMA networks (such as X.25, Frame Relay, and SMDS) as broadcast networks. This feature saves you from needing to configure neighbors, as described in the "Configuring OSPF for Nonbroadcast Networks" sectionlater in this module.

Configuring NBMA networks as either broadcast or nonbroadcast assumes that there are virtual circuits (VCs) from every router to every router or fully meshed network. This is not true for some cases, for example, because of cost constraints, or when you have only a partially meshed network. In these cases, you can configure the OSPF network type as a point-to-multipoint network. Routing between two routers not directly connected will go through the router that has VCs to both routers. Note that you need not configure neighbors when using this feature.

An OSPF point-to-multipoint interface is defined as a numbered point-to-point interface having one or more neighbors. It creates multiple host routes. An OSPF point-to-multipoint network has the following benefits compared to NBMA and point-to-point networks:

- Point-to-multipoint is easier to configure because it requires no configuration of neighbor commands, it consumes only one IP subnet, and it requires no designated router election.

- It costs less because it does not require a fully meshed topology.

- It is more reliable because it maintains connectivity in the event of VC failure.

On point-to-multipoint, broadcast networks, there is no need to specify neighbors. However, you can specify neighbors with the neighbor router configuration command, in which case you should specify a cost to that neighbor.

Before the point-to-multipoint keyword was added to the ip ospf network interface configuration command, some OSPF point-to-multipoint protocol traffic was treated as multicast traffic. Therefore, the neighbor router configuration command was not needed for point-to-multipoint interfaces because multicast took care of the traffic. Hello, update, and acknowledgment messages were sent using multicast. In particular, multicast hello messages discovered all neighbors dynamically.

On any point-to-multipoint interface (broadcast or not), the Cisco IOS software assumed that the cost to each neighbor was equal. The cost was configured with the ip ospf cost interface confutation command. In reality, the bandwidth to each neighbor is different, so the cost should differ. With this feature, you can configure a separate cost to each neighbor. This feature applies to point-to-multipoint interfaces only.

Because many routers might be attached to an OSPF network, a designated router is selected for the network. Special configuration parameters are needed in the designated router selection if broadcast capability is not configured.

These parameters need only be configured in those devices that are themselves eligible to become the designated router or backup designated router (in other words, routers with a nonzero router priority value).

You can specify the following neighbor parameters, as required:

- Priority for a neighboring router

- Nonbroadcast poll interval

On point-to-multipoint, nonbroadcast networks, use the neighbor router configuration command to identify neighbors. Assigning a cost to a neighbor is optional.

Prior to Cisco IOS Release 12.0, some customers were using point-to-multipoint on nonbroadcast media (such as classic IP over ATM), so their routers could not dynamically discover their neighbors. This feature allows the neighbor router configuration command to be used on point-to-multipoint interfaces.

On any point-to-multipoint interface (broadcast or not), the Cisco IOS software assumed the cost to each neighbor was equal. The cost was configured with the ip ospf cost interface configuration command. In reality, the bandwidth to each neighbor is different, so the cost should differ. With this feature, you can configure a separate cost to each neighbor. This feature applies to point-to-multipoint interfaces only.

Our OSPF software allows you to configure several area parameters. These area parameters, shown in the following task table, include authentication, defining stub areas, and assigning specific costs to the default summary route. Authentication allows password-based protection against unauthorized access to an area.

Stub areas are areas into which information on external routes is not sent. Instead, there is a default external route generated by the ABR, into the stub area for destinations outside the autonomous system. To take advantage of the OSPF stub area support, default routing must be used in the stub area. To further reduce the number of LSAs sent into a stub area, you can configure the no-summary keyword of the area stub router configuration command on the ABR to prevent it from sending summary link advertisement (LSAs Type 3) into the stub area.

The OSPF NSSA feature is described by RFC 3101. In Cisco IOS Release 15.1(2)S and later releases, RFC 3101 replaces RFC 1587. RFC 3101 is backward compatible with RFC 1587. For a detailed list of differences between them, see Appendix F of RFC 3101. NSSA support was first integrated into Cisco IOS Release 11.2. OSPF NSSA is a nonproprietary extension of the existing OSPF stub area feature.

RFC 3101 support enhances both the Type 7 autonomous-system external routing calculation and the translation of Type 7 LSAs into Type 5 LSAs. For more information, see RFC 3101.

Use NSSA to simplify administration if you are an Internet service provider (ISP) or a network administrator that must connect a central site that is using OSPF to a remote site that is using a different routing protocol.

Prior to NSSA, the connection between the corporate site border router and the remote router could not be run as an OSPF stub area because routes for the remote site could not be redistributed into the stub area, and two routing protocols needed to be maintained. A simple protocol such as RIP was usually run and handled the redistribution. With NSSA, you can extend OSPF to cover the remote connection by defining the area between the corporate router and the remote router as an NSSA.

As with OSPF stub areas, NSSA areas cannot be injected with distributed routes via Type 5 LSAs. Route redistribution into an NSSA area is possible only with a special type of LSA that is known as Type 7 that can exist only in an NSSA area. An NSSA ASBR generates the Type 7 LSA so that the routes can be redistributed, and an NSSA ABR translates the Type 7 LSA into a Type 5 LSA, which can be flooded throughout the whole OSPF routing domain. Summarization and filtering are supported during the translation.

Cisco IOS Release 15.1(2)S and later releases support RFC 3101, which allows you to configure an NSSA ABR router as a forced NSSA LSA translator. This means that the NSSA ABR router will unconditionally assume the role of LSA translator, preempting the default behavior, which would only include it among the candidates to be elected as translator.

Note

Even a forced translator might not translate all LSAs; translation depends on the contents of each LSA.

The figure below shows a network diagram in which OSPF Area 1 is defined as the stub area. The Enhanced Interior Gateway Routing Protocol (EIGRP) routes cannot be propagated into the OSPF domain because routing redistribution is not allowed in the stub area. However, once OSPF Area 1 is defined as an NSSA, an NSSA ASBR can inject the EIGRP routes into the OSPF NSSA by creating Type 7 LSAs.

OSPF NSSA

The redistributed routes from the RIP router will not be allowed into OSPF Area 1 because NSSA is an extension to the stub area. The stub area characteristics will still exist, including the exclusion of Type 5 LSAs.

Route summarization is the consolidation of advertised addresses. This feature causes a single summary route to be advertised to other areas by an ABR. In OSPF, an ABR will advertise networks in one area into another area. If the network numbers in an area are assigned in a way such that they are contiguous, you can configure the ABR to advertise a summary route that covers all the individual networks within the area that fall into the specified range.

When routes from other protocols are redistributed into OSPF (as described in the module “Configuring IP Routing Protocol-Independent Features”), each route is advertised individually in an external LSA. However, you can configure the Cisco IOS software to advertise a single route for all the redistributed routes that are covered by a specified network address and mask. Doing so helps decrease the size of the OSPF link-state database.

In OSPF, all areas must be connected to a backbone area. If there is a break in backbone continuity, or the backbone is purposefully partitioned, you can establish a virtual link. The two endpoints of a virtual link are ABRs. The virtual link must be configured in both routers. The configuration information in each router consists of the other virtual endpoint (the other ABR) and the nonbackbone area that the two routers have in common (called the transit area). Note that virtual links cannot be configured through stub areas.

You can force an ASBR to generate a default route into an OSPF routing domain. Whenever you specifically configure redistribution of routes into an OSPF routing domain, the router automatically becomes an ASBR. However, an ASBR does not, by default, generate a default route into the OSPF routing domain.

You can configure OSPF to look up Domain Naming System (DNS) names for use in all OSPF show EXEC command displays. You can use this feature to more easily identify a router, because the router is displayed by name rather than by its router ID or neighbor ID.

OSPF uses the largest IP address configured on the interfaces as its router ID. If the interface associated with this IP address is ever brought down, or if the address is removed, the OSPF process must recalculate a new router ID and resend all its routing information out its interfaces.

If a loopback interface is configured with an IP address, the Cisco IOS software will use this IP address as its router ID, even if other interfaces have larger IP addresses. Because loopback interfaces never go down, greater stability in the routing table is achieved.

OSPF automatically prefers a loopback interface over any other kind, and it chooses the highest IP address among all loopback interfaces. If no loopback interfaces are present, the highest IP address in the router is chosen. You cannot tell OSPF to use any particular interface.

In Cisco IOS Release 10.3 and later releases, by default OSPF calculates the OSPF metric for an interface according to the bandwidth of the interface. For example, a 64-kbps link gets a metric of 1562, and a T1 link gets a metric of 64.

The OSPF metric is calculated as the ref-bw value divided by the bandwidth value, with the ref-bw value equal to 108 by default, and the bandwidth value determined by the bandwidth interface configuration command. The calculation gives FDDI a metric of 1. If you have multiple links with high bandwidth, you might want to specify a larger number to differentiate the cost on those links.

An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual router or a group of routers. Numerically, an administrative distance is an integer from 0 to 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.

OSPF uses three different administrative distances: intra-area, interarea, and external. Routes within an area are intra-area; routes to another area are interarea; and routes from another routing domain learned via redistribution are external. The default distance for each type of route is 110.

Because simplex interfaces between two devices on an Ethernet represent only one network segment, for OSPF you must configure the sending interface to be a passive interface. This configuration prevents OSPF from sending hello packets for the sending interface. Both devices are able to see each other via the hello packet generated for the receiving interface.

You can configure the delay time between when OSPF receives a topology change and when it starts a shortest path first (SPF) calculation. You can also configure the hold time between two consecutive SPF calculations.

The OSPF on-demand circuit is an enhancement to the OSPF protocol that allows efficient operation over on-demand circuits such as ISDN, X.25 switched virtual circuits (SVCs), and dialup lines. This feature supports RFC 1793, Extending OSPF to Support Demand Circuits.

Prior to this feature, OSPF periodic hello and LSA updates would be exchanged between routers that connected the on-demand link, even when no changes occurred in the hello or LSA information.

With this feature, periodic hellos are suppressed and the periodic refreshes of LSAs are not flooded over the demand circuit. These packets bring up the link only when they are exchanged for the first time, or when a change occurs in the information they contain. This operation allows the underlying data link layer to be closed when the network topology is stable.

This feature is useful when you want to connect telecommuters or branch offices to an OSPF backbone at a central site. In this case, OSPF for on-demand circuits allows the benefits of OSPF over the entire domain, without excess connection costs. Periodic refreshes of hello updates, LSA updates, and other protocol overhead are prevented from enabling the on-demand circuit when there is no “real” data to send.

Overhead protocols such as hellos and LSAs are transferred over the on-demand circuit only upon initial setup and when they reflect a change in the topology. This means that critical changes to the topology that require new SPF calculations are sent in order to maintain network topology integrity. Periodic refreshes that do not include changes, however, are not sent across the link.

The OSPF LSA group pacing feature allows the router to group OSPF LSAs and pace the refreshing, checksumming, and aging functions. The group pacing results in more efficient use of the router.

The router groups OSPF LSAs and paces the refreshing, checksumming, and aging functions so that sudden increases in CPU usage and network resources are avoided. This feature is most beneficial to large OSPF networks.

OSPF LSA group pacing is enabled by default. For typical customers, the default group pacing interval for refreshing, checksumming, and aging is appropriate and you need not configure this feature.

Original LSA Behavior

Each OSPF LSA has an age, which indicates whether the LSA is still valid. Once the LSA reaches the maximum age (1 hour), it is discarded. During the aging process, the originating router sends a refresh packet every 30 minutes to refresh the LSA. Refresh packets are sent to keep the LSA from expiring, whether there has been a change in the network topology or not. Checksumming is performed on all LSAs every 10 minutes. The router keeps track of LSAs that it generates and LSAs that it receives from other routers. The router refreshes LSAs that it generated; it ages the LSAs that it received from other routers.

Prior to the LSA group pacing feature, the Cisco software would perform refreshing on a single timer and checksumming and aging on another timer. In the case of refreshing, for example, the software would scan the whole database every 30 minutes, refreshing every LSA that the router generated, no matter how old it was. The figure below illustrates all the LSAs being refreshed at once. This process wasted CPU resources because only a small portion of the database needed to be refreshed. A large OSPF database (several thousand LSAs) could have thousands of LSAs with different ages. Refreshing on a single timer resulted in the age of all LSAs becoming synchronized, which resulted in much CPU processing at once. Furthermore, a large number of LSAs could cause a sudden increase of network traffic, consuming a large amount of network resources in a short time.

OSPF LSAs on a Single Timer Without Group Pacing

LSA Group Pacing with Multiple Timers

Configuring each LSA to have its own timer avoids excessive CPU processing and sudden network-traffic increase. To again use the example of refreshing, each LSA gets refreshed when it is 30 minutes old, independent of other LSAs. So the CPU is used only when necessary. However, LSAs being refreshed at frequent, random intervals would require many packets for the few refreshed LSAs that the router must send, which would be inefficient use of bandwidth.

Therefore, the router delays the LSA refresh function for an interval of time instead of performing it when the individual timers are reached. The accumulated LSAs constitute a group, which is then refreshed and sent out in one packet or more. Thus, the refresh packets are paced, as are the checksumming and aging. The pacing interval is configurable; it defaults to 4 minutes, which is randomized to further avoid synchronization.

The figure below illustrates the case of refresh packets. The first timeline illustrates individual LSA timers; the second timeline illustrates individual LSA timers with group pacing.

OSPF LSAs on Individual Timers with Group Pacing

The group pacing interval is inversely proportional to the number of LSAs that the router is refreshing, checksumming, and aging. For example, if you have approximately 10,000 LSAs, decreasing the pacing interval would benefit you. If you have a very small database (40 to 100 LSAs), increasing the pacing interval to 10 to 20 minutes might benefit you slightly.

The default value of pacing between LSA groups is 240 seconds (4 minutes). The range is from 10 seconds to 1800 seconds (30 minutes).

By default, OSPF floods new LSAs over all interfaces in the same area, except the interface on which the LSA arrives. Some redundancy is desirable, because it ensures robust flooding. However, too much redundancy can waste bandwidth and might destabilize the network due to excessive link and CPU usage in certain topologies. An example would be a fully meshed topology.

You can block OSPF flooding of LSAs in two ways, depending on the type of networks:

- On broadcast, nonbroadcast, and point-to-point networks, you can block flooding over specified OSPF interfaces.

- On point-to-multipoint networks, you can block flooding to a specified neighbor.

The growth of the Internet has increased the importance of scalability in IGPs such as OSPF. By design, OSPF requires LSAs to be refreshed as they expire after 3600 seconds. Some implementations have tried to improve the flooding by reducing the frequency to refresh from 30 minutes to about 50 minutes. This solution reduces the amount of refresh traffic but requires at least one refresh before the LSA expires. The OSPF flooding reduction solution works by reducing unnecessary refreshing and flooding of already known and unchanged information. To achieve this reduction, the LSAs are now flooded with the higher bit set. The LSAs are now set as “do not age.”

Cisco routers do not support LSA Type 6 Multicast OSPF (MOSPF), and they generate syslog messages if they receive such packets. If the router is receiving many MOSPF packets, you might want to configure the router to ignore the packets and thus prevent a large number of syslog messages.

The former OSPF implementation for sending update packets needed to be more efficient. Some update packets were getting lost in cases where the link was slow, a neighbor could not receive the updates quickly enough, or the router was out of buffer space. For example, packets might be dropped if either of the following topologies existed:

- A fast router was connected to a slower router over a point-to-point link.

- During flooding, several neighbors sent updates to a single router at the same time.

OSPF update packets are now automatically paced so they are not sent less than 33 milliseconds apart. Pacing is also added between resends to increase efficiency and minimize lost retransmissions. Also, you can display the LSAs waiting to be sent out an interface. The benefit of pacing is that OSPF update and retransmission packets are sent more efficiently. There are no configuration tasks for this feature; it occurs automatically.

You can display specific statistics such as the contents of IP routing tables, caches, and databases. Information provided can be used to determine resource utilization and solve network problems. You can also display information about node reachability and discover the routing path that your device packets are taking through the network.

Restrictions for OSPF

On systems with a large number of interfaces, it may be possible to configure OSPF such that the number of links advertised in the router LSA causes the link-state update packet to exceed the size of a “huge” Cisco buffer. To resolve this problem, reduce the number of OSPF links or increase the huge buffer size by entering the buffers huge size size command.

A link-state update packet containing a router LSA typically has a fixed overhead of 196 bytes, and an additional 12 bytes are required for each link description. With a huge buffer size of 18024 bytes, there can be a maximum of 1485 link descriptions.

Because the maximum size of an IP packet is 65,535 bytes, there is still an upper bound on the number of links possible on a router.

How to Configure OSPF

To configure OSPF, perform the tasks described in the following sections. The tasks in the “Enabling OSPF” section are required; the tasks in the remaining sections are optional, but might be required for your application. For information about the maximum number of interfaces, see the “Restrictions for OSPF” section.

- Enabling OSPF

- Configuring OSPF Interface Parameters

- Configuring OSPFv2 NSSA

- Configuring OSPF over Different Physical Networks

- Configuring OSPF Area Parameters

- Configuring OSPF NSSA Parameters

- Configuring Route Summarization Between OSPF Areas

- Configuring Route Summarization When Redistributing Routes into OSPF

- Establishing Virtual Links

- Generating a Default Route

- Configuring Lookup of DNS Names

- Forcing the Router ID Choice with a Loopback Interface

- Controlling Default Metrics

- Changing the OSPF Administrative Distances

- Configuring OSPF on Simplex Ethernet Interfaces

- Configuring Route Calculation Timers

- Configuring OSPF over On-Demand Circuits

- Logging Neighbors Going Up or Down

- Changing the LSA Group Pacing Interval

- Blocking OSPF LSA Flooding

- Reducing LSA Flooding

- Ignoring MOSPF LSA Packets

- Displaying OSPF Update Packet Pacing

- Monitoring and Maintaining OSPF

Enabling OSPF

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    network ip-address wildcard-mask area area-id

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

network ip-address wildcard-mask area area-id

Example:

Device(config-router)# network 192.168.129.16 0.0.0.3 area 20

Defines an interface on which OSPF runs and defines the area ID for that interface.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring OSPF Interface Parameters

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ip ospf cost cost

5.    ip ospf retransmit-interval seconds

6.    ip ospf transmit-delay seconds

7.    ip ospf priority number-value

8.    ip ospf hello-interval seconds

9.    ip ospf dead-interval seconds

10.    ip ospf authentication-key key

11.    ip ospf message-digest-key key-id md5 key

12.    ip ospf authentication [message-digest | null]

13.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface Gigabitethernet 0/0

Configures an interface type and enters interface configuration mode.

Step 4

ip ospf cost cost

Example:

Device(config-if)# ip ospf cost 65

Explicitly specifies the cost of sending a packet on an OSPF interface.

Step 5

ip ospf retransmit-interval seconds

Example:

Device(config-if)# ip ospf retransmit-interval 1

Specifies the number of seconds between link-state advertisement (LSA) retransmissions for adjacencies belonging to an OSPF interface.

Step 6

ip ospf transmit-delay seconds

Example:

Device(config-if)# ip ospf transmit-delay

Sets the estimated number of seconds required to send a link-state update packet on an OSPF interface.

Step 7

ip ospf priority number-value

Example:

Device(config-if)# ip ospf priority 1

Sets priority to help determine the OSPF designated router for a network.

Step 8

ip ospf hello-interval seconds

Example:

Device(config-if)# ip ospf hello-interval 1

Specifies the length of time between the hello packets that the Cisco IOS software sends on an OSPF interface.

Step 9

ip ospf dead-interval seconds

Example:

Device(config-if)# ip ospf dead-interval 1

Sets the number of seconds that a device must wait before it declares a neighbor OSPF router down because it has not received a hello packet.

Step 10

ip ospf authentication-key key

Example:

Device(config-if)# ip ospf authentication-key 1

Assigns a password to be used by neighboring OSPF routers on a network segment that is using the OSPF simple password authentication.

Step 11

ip ospf message-digest-key key-id md5 key

Example:

Device(config-if)# ip ospf message-digest-key 1 md5 23456789

Enables OSPF MD5 authentication. The values for the key-id and key arguments must match values specified for other neighbors on a network segment.

Step 12

ip ospf authentication [message-digest | null]

Example:

Device(config-if)# ip ospf authentication message-digest

Specifies the authentication type for an interface.

Step 13

end

Example:

Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Configuring OSPFv2 NSSA

- Configuring an OSPFv2 NSSA Area and Its Parameters

- Configuring an NSSA ABR as a Forced NSSA LSA Translator

- Disabling RFC 3101 Compatibility and Enabling RFC 1587 Compatibility

Configuring an OSPFv2 NSSA Area and Its Parameters

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [autonomous-system-number] [metric {metric-value | transparent}] [metric-type type-value] [match {internal | external 1 | external 2}] [tag tag-value] [route-map map-tag] [subnets] [nssa-only]

5.    network ip-address wildcard-mask area area-id

6.    area area-id nssa [no-redistribution] [default-information-originate [metric] [metric-type]] [no-summary] [nssa-only]

7.    summary-address prefix mask [not-advertise] [tag tag] [nssa-only]

8.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 10

Enables OSPF routing and enters router configuration mode.

- The process-id argument identifies the OSPF process. The range is from 1 to 65535.

Step 4

redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [autonomous-system-number] [metric {metric-value | transparent}] [metric-type type-value] [match {internal | external 1 | external 2}] [tag tag-value] [route-map map-tag] [subnets] [nssa-only]

Example:

Device(config-router)# redistribute rip subnets

Redistributes routes from one routing domain to another routing domain.

- In the example, Routing Information Protocol (RIP) subnets are redistributed into the OSPF domain.

Step 5

network ip-address wildcard-mask area area-id

Example:

Device(config-router)# network 192.168.129.11 0.0.0.255 area 1

Defines the interfaces on which OSPF runs and the area ID for those interfaces.

Step 6

area area-id nssa [no-redistribution] [default-information-originate [metric] [metric-type]] [no-summary] [nssa-only]

Example:

Device(config-router)# area 1 nssa

Configures a Not-So-Stubby Area (NSSA) area.

Step 7

summary-address prefix mask [not-advertise] [tag tag] [nssa-only]

Example:

Device(config-router)# summary-address 10.1.0.0 255.255.0.0 not-advertise

Controls the route summarization and filtering during the translation and limits the summary to NSSA areas.

Step 8

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring an NSSA ABR as a Forced NSSA LSA Translator

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    area area-id nssa translate type7 always

5.    area area-id nssa translate type7 suppress-fa

6.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 1

Enables OSPF routing and enters router configuration mode.

- The process-id argument identifies the OSPF process. The range is from 1 to 65535.

Step 4

area area-id nssa translate type7 always

Example:

Device(config-router)# area 10 nssa translate type7 always

Configures a Not-So-Stubby Area Area Border Router (NSSA ABR) device as a forced NSSA Link State Advertisement (LSA) translator.

Note:
You can use the always keyword in the area nssa translate command to configure an NSSA ABR device as a forced NSSA LSA translator. This command can be used if RFC 3101 is disabled and RFC 1587 is used.

Step 5

area area-id nssa translate type7 suppress-fa

Example:

Device(config-router)# area 10 nssa translate type7 suppress-fa

Allows ABR to suppress the forwarding address in translated Type-5 LSA.

Step 6

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Disabling RFC 3101 Compatibility and Enabling RFC 1587 Compatibility

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    compatible rfc1587

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 1

Enables OSPF routing and enters router configuration mode.

- The process-id argument identifies the OSPF process.

- Use router ospf process-id command to enable OSPFv2 routing.

Step 4

compatible rfc1587

Example:

Device(config-router)# compatible rfc1587

Enables the device to be RFC 1587 compliant.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring OSPF over Different Physical Networks

- Configuring OSPF for Point-to-Multipoint Broadcast Networks

- Configuring OSPF for Nonbroadcast Networks

Configuring OSPF for Point-to-Multipoint Broadcast Networks

SUMMARY STEPS

1.    configure terminal

2.    interface type number

3.    ip ospf network point-to-multipoint

4.    exit

5.    router ospf process-id

6.    neighbor ip-address [cost number]

DETAILED STEPS

Command or Action

Purpose

Step 1

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 2

interface type number

Example:

Device(config)# interface gigabitethernet 0/0/0

Specifies an interface type and number, and enters interface configuration mode.

Step 3

ip ospf network point-to-multipoint

Example:

Device#(config-if) ip ospf network point-to-multipoint

Configures an interface as point-to-multipoint for broadcast media.

Step 4

exit

Example:

Device#(config-if) exit

Enters global configuration mode.

Step 5

router ospf process-id

Example:

Device#(config) router ospf 109

Configures an OSPF routing process and enters router configuration mode.

Step 6

neighbor ip-address [cost number]

Example:

Device#(config-router) neighbor 192.168.3.4 cost 180

Specifies a neighbor and assigns a cost to the neighbor.

Note:
Repeat this step for each neighbor if you want to specify a cost. Otherwise, neighbors will assume the cost of the interface, based on the ip ospf cost interface configuration command.

Configuring OSPF for Nonbroadcast Networks

SUMMARY STEPS

1.    configure terminal

2.    interface type number

3.    ip ospf network point-to-multipoint non-broadcast

4.    exit

5.    router ospf process-id

6.    neighbor ip-address [cost number]

DETAILED STEPS

Command or Action

Purpose

Step 1

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 2

interface type number

Example:

Device(config)# interface gigabitethernet 0/0/0

Specifies an interface type and number, and enters interface configuration mode.

Step 3

ip ospf network point-to-multipoint non-broadcast

Example:

Device#(config-if) ip ospf network point-to-multipoint non-broadcast

Configures an interface as point-to-multipoint for nonbroadcast media.

Step 4

exit

Example:

Device#(config-if) exit

Enters global configuration mode.

Step 5

router ospf process-id

Example:

Device#(config) router ospf 109

Configures an OSPF routing process and enters router configuration mode.

Step 6

neighbor ip-address [cost number]

Example:

Device#(config-router) neighbor 192.168.3.4 cost 180

Specifies a neighbor and assigns a cost to the neighbor.

Note:
Repeat this step for each neighbor if you want to specify a cost. Otherwise, neighbors will assume the cost of the interface, based on the ip ospf cost interface configuration command.

Configuring OSPF Area Parameters

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    area area-id authentication

5.    area area-id stub [no summary]

6.    area area-id default-cost cost

7.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 10

Enables OSPF routing and enters router configuration mode.

Step 4

area area-id authentication

Example:

Device(config-router)# area 10.0.0.0 authentication

Enables authentication for an OSPF area.

Step 5

area area-id stub [no summary]

Example:

Device(config-router)# area 10.0.0.0 stub no-summary

Defines an area to be a stub area.

Step 6

area area-id default-cost cost

Example:

Device(config-router)# area 10.0.0.0 default-cost 1

Specifies a cost for the default summary route that is sent into a stub area or not-so-stubby area (NSSA)

Step 7

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring OSPF NSSA Parameters

- Prerequisites

Prerequisites

Evaluate the following considerations before you implement this feature:

- You can set a Type 7 default route that can be used to reach external destinations. When configured, the device generates a Type 7 default into the Not-So-Stubby Area (NSSA or the NSSA Area Border Router (ABR).

- Every device within the same area must agree that the area is NSSA; otherwise, the devices cannot communicate.

- Configuring OSPF NSSA Area Parameters

Configuring OSPF NSSA Area Parameters

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    area area-id nssa [no-redistribution] [default-information-originate]

5.    summary-address prefix mask [not-advertise] [tag tag ] [nssa-only]

6.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing, which places the router in router configuration mode.

Step 4

area area-id nssa [no-redistribution] [default-information-originate]

Example:

Device(config-router)# area 10 nssa no-redistribution

Defines an area to be an NSSA.

Step 5

summary-address prefix mask [not-advertise] [tag tag ] [nssa-only]

Example:

Device(config-router)# summary-address 10.1.0.0 255.255.0.0 not-advertise

Controls the summarization and filtering during the translation and limits the summary to NSSA areas.

Step 6

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring Route Summarization Between OSPF Areas

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    area area-id range ip-address mask [advertise | not-advertise] [cost cost ]

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing, which places the router in router configuration mode.

Step 4

area area-id range ip-address mask [advertise | not-advertise] [cost cost ]

Example:

Device(config-router)# area 0 range 192.168.110.0 255.255.0.0

Specifies an address range for which a single route will be advertised.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring Route Summarization When Redistributing Routes into OSPF

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    area area-id nssa [no-redistribution] [default-information-originate]

5.    summary-address {ip-address mask | prefix mask } [not-advertise] [tag tag ]

6.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing, which places the router in router configuration mode.

Step 4

area area-id nssa [no-redistribution] [default-information-originate]

Example:

Device(config-router)# area 10 nssa no-redistribution

Defines an area to be an NSSA.

Step 5

summary-address {ip-address mask | prefix mask } [not-advertise] [tag tag ]

Example:

Device(config-router)# summary-address 10.1.0.0 255.255.0.0 not-advertise

Specifies an address and mask that covers redistributed routes, so only one summary route is advertised. Use the optional not-advertise keyword to filter out a set of routes the summarization and filtering during the translation and limits the summary to NSSA areas.

Step 6

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Establishing Virtual Links

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    area area-id virtual-link router-id [authentication] [message-digest | null]] [hello-interval seconds] [retransmit-interval seconds] [transmit-delay seconds] [dead-interval seconds] [authentication-key key] [message-digest-key key] [md5 key]

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Router> router ospf 109

Enables OSPF routing, which places the router in router configuration mode.

Step 4

area area-id virtual-link router-id [authentication] [message-digest | null]] [hello-interval seconds] [retransmit-interval seconds] [transmit-delay seconds] [dead-interval seconds] [authentication-key key] [message-digest-key key] [md5 key]

Example:

Device(config-router)# area 10 virtual link 1

Establishes a virtual link.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Generating a Default Route

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    default-information originate [always] [metric metric-value] [metric-type type-value] [route-map map-name]

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

default-information originate [always] [metric metric-value] [metric-type type-value] [route-map map-name]

Example:

Device(config-router)# default-information originate always

Forces the ASBR to generate a default route into the OSPF routing domain.

Note:
The always keyword includes the following exception when a route map is used. When a route map is used, the origination of the default route by OSPF is not bound to the existence of a default route in the routing table.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring Lookup of DNS Names

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip ospf name-lookup

4.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ip ospf name-lookup

Example:

Device# ip ospf name-lookup

Enables OSPF routing and enters router configuration mode.

Step 4

end

Example:

Device(config)# end

Exits global configuration mode and returns to privileged EXEC mode.

Forcing the Router ID Choice with a Loopback Interface

SUMMARY STEPS

1.    configure terminal

2.    interface type number

3.    ip address ip-address mask

DETAILED STEPS

Command or Action

Purpose

Step 1

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 2

interface type number

Example:

Device(config)# interface loopback 0

Creates a loopback interface and enters interface configuration mode.

Step 3

ip address ip-address mask

Example:

Device#(config-if) ip address 192.108.1.27 255.255.255.0

Assigns an IP address to this interface.

Controlling Default Metrics

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    auto-cost reference-bandwidth ref-bw

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

auto-cost reference-bandwidth ref-bw

Example:

Device(config-router)# auto-cost reference-bandwidth 101

Differentiates high -bandwidth links.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Changing the OSPF Administrative Distances

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    distance ospf {intra-area | inter-area | external} dist

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

distance ospf {intra-area | inter-area | external} dist

Example:

Device(config-router)# distance ospf external 200

Changes the OSPF distance values.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring OSPF on Simplex Ethernet Interfaces

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    passive-interface interface-type interface-number

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing, which places the router in router configuration mode.

Step 4

passive-interface interface-type interface-number

Example:

Device(config-router)# passive-interface Gigabitethernet 1/0

Suppresses the sending of hello packets through the specified interface.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring Route Calculation Timers

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    timers throttle spf spf-start spf-hold spf-max-wait

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

timers throttle spf spf-start spf-hold spf-max-wait

Example:

Device(config-router)# timers throttle spf 5 1000 9000

Configures route calculation timers.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Configuring OSPF over On-Demand Circuits

SUMMARY STEPS

1.    router ospf process-id

2.    interface type number

3.    ip ospf demand-circuit

DETAILED STEPS

Command or Action

Purpose

Step 1

router ospf process-id

Enables OSPF operation.

Step 2

interface type number

Enters interface configuration mode.

Step 3

ip ospf demand-circuit

Configures OSPF over an on-demand circuit.

What to Do Next

Note

You can prevent an interface from accepting demand-circuit requests from other routers to by specifying the ignore keyword in the ip ospf demand-circuit command.

- Prerequisites

Prerequisites

Evaluate the following considerations before implementing the On-Demand Circuits feature:

- Because LSAs that include topology changes are flooded over an on-demand circuit, we recommend that you put demand circuits within OSPF stub areas or within NSSAs to isolate the demand circuits from as many topology changes as possible.

- Every router within a stub area or NSSA must have this feature loaded in order to take advantage of the on-demand circuit functionality. If this feature is deployed within a regular area, all other regular areas must also support this feature before the demand circuit functionality can take effect because Type 5 external LSAs are flooded throughout all areas.

- Hub-and-spoke network topologies that have a point-to-multipoint (P2MP) OSPF interface type on a hub might not revert to nondemand circuit mode when needed. You must simultaneously reconfigure OSPF on all interfaces on the P2MP segment when reverting them from demand circuit mode to nondemand circuit mode.

- Do not implement this feature on a broadcast-based network topology because the overhead protocols (such as hello and LSA packets) cannot be successfully suppressed, which means the link will remain up.

- Configuring the router for an OSPF on-demand circuit with an asynchronous interface is not a supported configuration. The supported configuration is to use dialer interfaces on both ends of the circuit. For more information, refer to Why OSPF Demand Circuit Keeps Bringing Up the Link .

Logging Neighbors Going Up or Down

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    log-adjacency-changes [detail]

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

log-adjacency-changes [detail]

Example:

Device(config-router)# log-adjacency-changes detail

Changes the group pacing of LSAs.
Note:
Configure the log-adjacency-changes command if you want to know about OSPF neighbors going up or down without turning on the debug ip ospf adjacency EXEC command because the log-adjacency-changes command provides a higher-level view of the peer relationship with less output. Configure the log-adjacency-changes detail command if you want to see messages for each state change.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Changing the LSA Group Pacing Interval

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    timers pacing lsa-group seconds

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

timers pacing lsa-group seconds

Example:

Device(config-router)# timers pacing lsa-group 60

Changes the group pacing of LSAs.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Blocking OSPF LSA Flooding

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ip ospf database-filter all out

5.    end

6.    configure terminal

7.    router ospf process-id

8.    neighbor ip-address database-filter all out

9.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface GigabitEthernet 0/0

Configures an interface type and enters interface configuration mode.

Step 4

ip ospf database-filter all out

Example:

Device(config-if)# ip ospf database-filter all out

Blocks the flooding of OSPF LSA packets to the interface.

Step 5

end

Example:

Device(config-interface)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Step 6

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 7

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 8

neighbor ip-address database-filter all out

Example:

Device(config-router)# neighbor 10.2.3.4 database-filter all out

On point-to-multipoint networks, this command blocks the flooding of OSPF LSA packets to the specified neighbor.

Step 9

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Reducing LSA Flooding

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ip ospf flood-reduction

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface GigabitEthernet 0/0

Configures an interface type and enters interface configuration mode.

Step 4

ip ospf flood-reduction

Example:

Device(config-if)# ip ospf flood-reduction

Suppresses the unnecessary flooding of LSAs in stable topologies.

Step 5

end

Example:

Device(config-interface)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Ignoring MOSPF LSA Packets

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    ignore sla mospf

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 109

Enables OSPF routing and enters router configuration mode.

Step 4

ignore sla mospf

Example:

Device(config-router)# ignore sla mospf

Prevents the router from generating syslog messages when it receives Multicast OSPF (MOSPF) LSA packets.

Step 5

end

Example:

Device(config-router)# end

Exits router configuration mode and returns to privileged EXEC mode.

Displaying OSPF Update Packet Pacing

SUMMARY STEPS

1.    enable

2.    show ip ospf flood-list interface-type interface-number

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ip ospf flood-list interface-type interface-number

Example:

Device# show ip ospf flood-list ethernet 1

Displays a list of LSAs waiting to be flooded over an interface.

Monitoring and Maintaining OSPF

SUMMARY STEPS

1.    enable

2.    show ip ospf [process-id]

3.    show ip ospf border-routers

4.    show ip ospf [process-id [area-id]] database

5.    show ip ospf [process-id [area-id]] database [database-summary]

6.    show ip ospf [process-id [area-id]] database [router] [self-originate]

7.    show ip ospf [process-id [area-id]] database [router] [adv-router [ip-address]]

8.    show ip ospf [process-id [area-id]] database [router] [link-state-id]

9.    show ip ospf [process-id [area-id]] database [network] [link-state-id]

10.    show ip ospf [process-id [area-id]] database [summary] [link-state-id]

11.    show ip ospf [process-id [area-id]] database [asbr-summary] [link-state-id]

12.    show ip ospf [process-id [area-id]] database [external] [link-state-id]

13.    show ip ospf [process-id [area-id]] database [nssa-external] [link-state-id]

14.    show ip ospf [process-id [area-id]] database [opaque-link] [link-state-id]

15.    show ip ospf [process-id [area-id]] database [opaque-area] [link-state-id]

16.    show ip ospf [process-id [area-id]] database [opaque-as] [link-state-id]

17.    show ip ospf flood-list interface-type interface-number

18.    show ip ospf flood-list interface-type interface-number

19.    show ip ospf interface interface-type interface-number

20.    show ip ospf neighbor [interface-type interface-number] [neighbor-id] [detail]

21.    show ip ospf request-list [neighbor] [interface] [interface-neighbor]

22.    show ip ospf retransmission-list [neighbor] [interface] [interface-neighbor]

23.    show ip ospf process-id summary-address [neighbor] [interface] [interface-neighbor]

24.    show ip ospf virtual-links

25.    clear ip ospf [process-id {process | redistribution | counters [neighbor [neighbor-interface] [neighbor-id]]}

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ip ospf [process-id]

Example:

Device> show ip ospf 1

Displays general information about OSPF routing processes.

Step 3

show ip ospf border-routers

Example:

Device> show ip ospf border-routers

Displays the internal OSPF routing table entries to the ABR and ASBR.

Step 4

show ip ospf [process-id [area-id]] database

Example:

Device> show ip ospf 1 1 database

Displays lists of information related to the OSPF database.

Step 5

show ip ospf [process-id [area-id]] database [database-summary]

Example:

Device> show ip ospf 1 1 database database-summary

Displays lists of information related to the OSPF database.

Step 6

show ip ospf [process-id [area-id]] database [router] [self-originate]

Example:

Device> show ip ospf 1 1 database router self-originate

Displays lists of information related to the OSPF database.

Step 7

show ip ospf [process-id [area-id]] database [router] [adv-router [ip-address]]

Example:

Device> show ip ospf 1 1 database router adv-router

Displays lists of information related to the OSPF database.

Step 8

show ip ospf [process-id [area-id]] database [router] [link-state-id]

Example:

Device> show ip ospf 1 1 database router 172.16.240.0

Displays lists of information related to the OSPF database.

Step 9

show ip ospf [process-id [area-id]] database [network] [link-state-id]

Example:

Device> show ip ospf 1 1 database network 172.16.240.0

Displays lists of information related to the OSPF database.

Step 10

show ip ospf [process-id [area-id]] database [summary] [link-state-id]

Example:

Device> show ip ospf 1 1 database summary 172.16.240.0

Displays lists of information related to the OSPF database.

Step 11

show ip ospf [process-id [area-id]] database [asbr-summary] [link-state-id]

Example:

Device> show ip ospf 1 1 database absr-summary 172.16.240.0

Displays lists of information related to the OSPF database.

Step 12

show ip ospf [process-id [area-id]] database [external] [link-state-id]

Example:

Device> show ip ospf 1 1 database external 172.16.240.0

Displays lists of information related to the OSPF database.

Step 13

show ip ospf [process-id [area-id]] database [nssa-external] [link-state-id]

Example:

Device> show ip ospf 1 1 database nssa-external 172.16.240.0

Displays lists of information related to the OSPF database.

Step 14

show ip ospf [process-id [area-id]] database [opaque-link] [link-state-id]

Example:

Device> show ip ospf 1 1 database opaque-link 172.16.240.0

Displays lists of information related to the OSPF database.

Step 15

show ip ospf [process-id [area-id]] database [opaque-area] [link-state-id]

Example:

Device> show ip ospf 1 1 database opaque-area 172.16.240.0

Displays lists of information related to the OSPF database.

Step 16

show ip ospf [process-id [area-id]] database [opaque-as] [link-state-id]

Example:

Device> show ip ospf 1 1 database opaque-as 172.16.240.0

Displays lists of information related to the OSPF database.

Step 17

show ip ospf flood-list interface-type interface-number

Example:

Device> show ip ospf 1 1 flood-list GigabitEthernet 1/0

Displays lists of information related to the OSPF database.

Step 18

show ip ospf flood-list interface-type interface-number

Example:

Device> show ip ospf flood-list GigabitEthernet 1/0

Displays a list of LSAs waiting to be flooded over an interface (to observe OSPF packet pacing).

Step 19

show ip ospf interface interface-type interface-number

Example:

Device> show ip ospf interface GigabitEthernet 0/0

Displays OSPF-related interface information.

Step 20

show ip ospf neighbor [interface-type interface-number] [neighbor-id] [detail]

Example:

Device> show ip ospf neighbor

Displays OSPF neighbor information on a per-interface basis.

Step 21

show ip ospf request-list [neighbor] [interface] [interface-neighbor]

Example:

Device> show ip ospf request-list

Displays a list of all LSAs requested by a router.

Step 22

show ip ospf retransmission-list [neighbor] [interface] [interface-neighbor]

Example:

Device> show ip ospf retransmission-list

Displays a list of all LSAs waiting to be re-sent.

Step 23

show ip ospf process-id summary-address [neighbor] [interface] [interface-neighbor]

Example:

Device> show ip ospf summary-address

Displays a list of all summary-address redistribution information configured under an OSPF process.

Step 24

show ip ospf virtual-links

Example:

Device> show ip ospf virtual-links

Displays OSPF-related virtual-link information.

Step 25

clear ip ospf [process-id {process | redistribution | counters [neighbor [neighbor-interface] [neighbor-id]]}

Example:

Device> clear ip ospf process

Clears redistribution based on the OSPF routing process ID. If the process-id value is not specified, all OSPF processes are cleared.

Configuration Examples for OSPF

- Example: OSPF Point-to-Multipoint

- Example: OSPF Point-to-Multipoint with Broadcast

- Example: OSPF Point-to-Multipoint with Nonbroadcast

- Example: Variable-Length Subnet Masks

- Example: Configuring OSPF NSSA

- Example: OSPF NSSA Area with RFC 3101 Disabled and RFC 1587 Active

- Example: OSPF Routing and Route Redistribution

- Examples: Route Map

- Example: Changing the OSPF Administrative Distances

- Example: OSPF over On-Demand Routing

- Example: LSA Group Pacing

- Example: Blocking OSPF LSA Flooding

- Example: Ignoring MOSPF LSA Packets

Example: OSPF Point-to-Multipoint

In the figure below, Router 1 uses data-link connection identifier (DLCI) 201 to communicate with Router 2, DLCI 202 to communicate with Router 4, and DLCI 203 to communicate with Router 3. Router 2 uses DLCI 101 to communicate with Router 1 and DLCI 102 to communicate with Router 3. Router 3 communicates with Router 2 (DLCI 401) and Router 1 (DLCI 402). Router 4 communicates with Router 1 (DLCI 301). Configuration examples follow the figure.

OSPF Point-to-Multipoint Example

Router 1 Configuration

hostname Router 1
!
interface serial 1
ip address 10.0.0.2 255.0.0.0
ip ospf network point-to-multipoint
encapsulation frame-relay
frame-relay map ip 10.0.0.1 201 broadcast
frame-relay map ip 10.0.0.3 202 broadcast
frame-relay map ip 10.0.0.4 203 broadcast
!
router ospf 1
network 10.0.0.0 0.0.0.255 area 0

Router 2 Configuration

hostname Router 2
!
interface serial 0
ip address 10.0.0.1 255.0.0.0
ip ospf network point-to-multipoint
encapsulation frame-relay
frame-relay map ip 10.0.0.2 101 broadcast
frame-relay map ip 10.0.0.4 102 broadcast
!
router ospf 1
network 10.0.0.0 0.0.0.255 area 0

Router 3 Configuration

hostname Router 3
!
interface serial 3
ip address 10.0.0.4 255.0.0.0
ip ospf network point-to-multipoint
encapsulation frame-relay
clock rate 1000000
frame-relay map ip 10.0.0.1 401 broadcast
frame-relay map ip 10.0.0.2 402 broadcast
!
router ospf 1
network 10.0.0.0 0.0.0.255 area 0

Router 4 Configuration

hostname Router 4
!
interface serial 2
ip address 10.0.0.3 255.0.0.0
ip ospf network point-to-multipoint
encapsulation frame-relay
clock rate 2000000
frame-relay map ip 10.0.0.2 301 broadcast
!
router ospf 1
network 10.0.0.0 0.0.0.255 area 0

Example: OSPF Point-to-Multipoint with Broadcast

The following example illustrates a point-to-multipoint network with broadcast:

interface Serial0
ip address 10.0.1.1 255.255.255.0
encapsulation frame-relay
ip ospf cost 100
ip ospf network point-to-multipoint
frame-relay map ip 10.0.1.3 202 broadcast
frame-relay map ip 10.0.1.4 203 broadcast
frame-relay map ip 10.0.1.5 204 broadcast
frame-relay local-dlci 200
!
router ospf 1
network 10.0.1.0 0.0.0.255 area 0
neighbor 10.0.1.5 cost 5
neighbor 10.0.1.4 cost 10

The following example shows the configuration of the neighbor at 10.0.1.3:

interface serial 0
ip address 10.0.1.3 255.255.255.0
ip ospf network point-to-multipoint
encapsulation frame-relay
frame-relay local-dlci 301
frame-relay map ip 10.0.1.1 300 broadcast
no shutdown
!
router ospf 1
network 10.0.1.0 0.0.0.255 area 0

The output shown for neighbors in the first configuration is as follows:

Device# show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
172.16.1.1           1   FULL/  -        00:01:50    10.0.1.5        Serial0
172.16.1.4           1   FULL/  -        00:01:47    10.0.1.4        Serial0
172.16.1.8           1   FULL/  -        00:01:45    10.0.1.3        Serial0

The route information in the first configuration is as follows:

Device# show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
Gateway of last resort is not set
C    1.0.0.0/8 is directly connected, Loopback0
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
O       10.0.1.3/32 [110/100] via 10.0.1.3, 00:39:08, Serial0
C       10.0.1.0/24 is directly connected, Serial0
O       10.0.1.5/32 [110/5] via 10.0.1.5, 00:39:08, Serial0
O       10.0.1.4/32 [110/10] via 10.0.1.4, 00:39:08, Serial0

Example: OSPF Point-to-Multipoint with Nonbroadcast

The following example illustrates a point-to-multipoint network with nonbroadcast:

interface Serial0
ip address 10.0.1.1 255.255.255.0
ip ospf network point-to-multipoint non-broadcast
encapsulation frame-relay
no keepalive
frame-relay local-dlci 200
frame-relay map ip 10.0.1.3 202
frame-relay map ip 10.0.1.4 203
frame-relay map ip 10.0.1.5 204
no shutdown
!
router ospf 1
network 10.0.1.0 0.0.0.255 area 0
neighbor 10.0.1.3 cost 5
neighbor 10.0.1.4 cost 10
neighbor 10.0.1.5 cost 15

The following example is the configuration for the router on the other side:

interface Serial9/2
ip address 10.0.1.3 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-multipoint non-broadcast
no ip mroute-cache
no keepalive
no fair-queue
frame-relay local-dlci 301
frame-relay map ip 10.0.1.1 300
no shutdown
!
router ospf 1
network 10.0.1.0 0.0.0.255 area 0

The output shown for neighbors in the first configuration is as follows:

Device# show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
172.16.1.1           1   FULL/  -        00:01:52    10.0.1.5        Serial0
172.16.1.4           1   FULL/  -        00:01:52    10.0.1.4        Serial0
172.16.1.8           1   FULL/  -        00:01:52    10.0.1.3        Serial0

Example: Variable-Length Subnet Masks

OSPF, static routes, and IS-IS support variable-length subnet masks (VLSMs). With VLSMs, you can use different masks for the same network number on different interfaces, which allows you to conserve IP addresses and more efficiently use available address space.

In the following example, a 30-bit subnet mask is used, leaving two bits of address space reserved for serial-line host addresses. There is sufficient host address space for two host endpoints on a point-to-point serial link.

interface ethernet 0
ip address 172.16.10.1 255.255.255.0
! 8 bits of host address space reserved for ethernets
interface serial 0
ip address 172.16.20.1 255.255.255.252
! 2 bits of address space reserved for serial lines
! Router is configured for OSPF and assigned AS 107
router ospf 107
! Specifies network directly connected to the router
network 172.16.0.0 0.0.255.255 area 0.0.0.0

Example: Configuring OSPF NSSA

In the following example, an Open Shortest Path First (OSPF) stub network is configured to include OSPF Area 0 and OSPF Area 1, using five devices. Device 3 is configured as the NSSA Autonomous System Border Router (ASBR). Device 2 configured to be the NSSA Area Border Router (ABR). OSPF Area 1 is defined as a Not-So-Stubby Area (NSSA).

Device 1

hostname Device1
!
interface Loopback1
ip address 10.1.0.1 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.0.1 255.255.255.0
ip ospf 1 area 0
no cdp enable
!
interface Serial10/0
description Device2 interface s11/0
ip address 192.168.10.1 255.255.255.0
ip ospf 1 area 1
serial restart-delay 0
no cdp enable
!
router ospf 1
area 1 nssa
!
end

Device 2

hostname Device2
!
!
interface Loopback1
ip address 10.1.0.2 255.255.255.255
!
interface Serial10/0
description Device1 interface s11/0
no ip address
shutdown
serial restart-delay 0
no cdp enable
!
interface Serial11/0
description Device1 interface s10/0
ip address 192.168.10.2 255.255.255.0
ip ospf 1 area 1
serial restart-delay 0
no cdp enable
!
interface Serial14/0
description Device3 interface s13/0
ip address 192.168.14.2 255.255.255.0
ip ospf 1 area 1
serial restart-delay 0
no cdp enable
!
router ospf 1
area 1 nssa
!
end

Device 3

hostname Device3
!
interface Loopback1
ip address 10.1.0.3 255.255.255.255
!
interface Ethernet3/0
ip address 192.168.3.3 255.255.255.0
no cdp enable
!
interface Serial13/0
description Device2 interface s14/0
ip address 192.168.14.3 255.255.255.0
ip ospf 1 area 1
serial restart-delay 0
no cdp enable
!
router ospf 1
log-adjacency-changes
area 1 nssa
redistribute rip subnets
!
router rip
version 2
redistribute ospf 1 metric 15
network 192.168.3.0
end

Device 4

hostname Device4
!
interface Loopback1
ip address 10.1.0.4 255.255.255.255
!
interface Ethernet3/0
ip address 192.168.3.4 255.255.255.0
no cdp enable
!
interface Ethernet4/1
ip address 192.168.41.4 255.255.255.0
!
router rip
version 2
network 192.168.3.0
network 192.168.41.0
!
end

Device 5

hostname Device5
!
interface Loopback1
ip address 10.1.0.5 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.0.10 255.255.255.0
ip ospf 1 area 0
no cdp enable
!
interface Ethernet1/1
ip address 192.168.11.10 255.255.255.0
ip ospf 1 area 0
!
router ospf 1
!
end

Example: OSPF NSSA Area with RFC 3101 Disabled and RFC 1587 Active

In the following example, the output for the show ip ospf and show ip ospf database nssa commands shows an Open Shortest Path First Not-So-Stubby Area (OSPF NSSA) area where RFC 3101 is disabled, RFC 1587 is active, and an NSSA Area Border Router (ABR) device is configured as a forced NSSA LSA translator. If RFC 3101 is disabled, the forced NSSA LSA translator remains inactive.

Device# show ip ospf

Routing Process "ospf 1" with ID 10.0.2.1
Start time: 00:00:25.512, Time elapsed: 00:01:02.200
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Supports NSSA (compatible with RFC 1587)
Event-log enabled, Maximum number of events: 1000, Mode: cyclic
Router is not originating router-LSAs with maximum metric
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Incremental-SPF disabled
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 0. Checksum Sum 0x000000
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 0 normal 0 stub 1 nssa
Number of areas transit capable is 0
External flood list length 0
IETF NSF helper support enabled
Cisco NSF helper support enabled
Reference bandwidth unit is 100 mbps
Area 1
Number of interfaces in this area is 1
It is a NSSA area
Configured to translate Type-7 LSAs, inactive (RFC3101 support
disabled)
Area has no authentication
SPF algorithm last executed 00:00:07.160 ago
SPF algorithm executed 3 times
Area ranges are
Number of LSA 3. Checksum Sum 0x0245F0
Number of opaque link LSA 0. Checksum Sum 0x000000
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0

The table below describes the show ip ospf display fields and their descriptions.

show ip ospf Field Descriptions

Field

Description

Supports NSSA (compatible with RFC 1587)

Specifies that RFC 1587 is active or that the OSPF NSSA area is RFC 1587 compatible.

Configured to translate Type-7 LSAs, inactive (RFC3101 support disabled)

Specifies that OSPF NSSA area has an ABR device configured to act as a forced translator of Type 7 LSAs. However, it is inactive because RFC 3101 is disabled

Device2# show ip ospf database nssa

Router Link States (Area 1)
LS age: 28
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 10.0.2.1
Advertising Router: 10.0.2.1
LS Seq Number: 80000004
Checksum: 0x5CA2
Length: 36
Area Border Router
AS Boundary Router
Unconditional NSSA translator
Number of Links: 1
Link connected to: a Stub Network
(Link ID) Network/subnet number: 192.0.2.5
(Link Data) Network Mask: 255.255.255.0
Number of MTID metrics: 0
TOS 0 Metrics: 10

The table below describes the show ip ospf database nssa display fields and their descriptions.

show ip ospf database nssa Field Descriptions

Field

Description

Unconditional NSSA translator

Specifies that NSSA ASBR device is a forced NSSA LSA translator

Example: OSPF Routing and Route Redistribution

OSPF typically requires coordination among many internal routers, ABRs, and ASBRs. At a minimum, OSPF-based routers can be configured with all default parameter values, with no authentication, and with interfaces assigned to areas.

Three types of examples follow:

- The first is a simple configuration illustrating basic OSPF commands.

- The second example illustrates a configuration for an internal router, ABR, and ASBRs within a single, arbitrarily assigned, OSPF autonomous system.

- The third example illustrates a more complex configuration and the application of various tools available for controlling OSPF-based routing environments.

- Example: Basic OSPF Configuration

- Example: Basic OSPF Configuration for Internal Router ABR and ASBRs

- Example: Complex Internal Router with ABR and ASBR

- Example: Complex OSPF Configuration for ABR

Example: Basic OSPF Configuration

The following example illustrates a simple OSPF configuration that enables OSPF routing process 9000, attaches Ethernet interface 0 to area 0.0.0.0, and redistributes RIP into OSPF and OSPF into RIP:

interface ethernet 0
ip address 10.93.1.1 255.255.255.0
ip ospf cost 1
!
interface ethernet 1
ip address 10.94.1.1 255.255.255.0
!
router ospf 9000
network 10.93.0.0 0.0.255.255 area 0.0.0.0
redistribute rip metric 1 subnets
!
router rip
network 10.94.0.0
redistribute ospf 9000
default-metric 1

Example: Basic OSPF Configuration for Internal Router ABR and ASBRs

The following example illustrates the assignment of four area IDs to four IP address ranges. In the example, OSPF routing process 109 is initialized, and four OSPF areas are defined: 10.9.50.0, 2, 3, and 0. Areas 10.9.50.0, 2, and 3 mask specific address ranges, and area 0 enables OSPF for all other networks.

router ospf 109
network 192.168.10.0 0.0.0.255 area 10.9.50.0
network 192.168.20.0 0.0.255.255 area 2
network 192.168.30.0 0.0.0.255 area 3
network 192.168.40.0 255.255.255.255 area 0
!
! Interface Ethernet0 is in area 10.9.50.0:
interface ethernet 0
ip address 192.168.10.5 255.255.255.0
!
! Interface Ethernet1 is in area 2:
interface ethernet 1
ip address 192.168.20.5 255.255.255.0
!
! Interface Ethernet2 is in area 2:
interface ethernet 2
ip address 192.168.20.7 255.255.255.0
!
! Interface Ethernet3 is in area 3:
interface ethernet 3
ip address 192.169.30.5 255.255.255.0
!
! Interface Ethernet4 is in area 0:
interface ethernet 4
ip address 192.168.40.1 255.255.255.0
!
! Interface Ethernet5 is in area 0:
interface ethernet 5
ip address 192.168.40.12 255.255.0.0

Each network area router configuration command is evaluated sequentially, so the order of these commands in the configuration is important. The Cisco software sequentially evaluates the address/wildcard-mask pair for each interface. See the network area command page in the Cisco IOS IP Routing: OSPF Command Reference for more information.

Consider the first network area command. Area ID 10.9.50.0 is configured for the interface on which subnet 192.168.10.0 is located. Assume that a match is determined for Ethernet interface 0. Ethernet interface 0 is attached to area 10.9.50.0 only.

The second network area command is evaluated next. For area 2, the same process is then applied to all interfaces (except Ethernet interface 0). Assume that a match is determined for Ethernet interface 1. OSPF is then enabled for that interface, and Ethernet interface 1 is attached to area 2.

This process of attaching interfaces to OSPF areas continues for all network area commands. Note that the last network area command in this example is a special case. With this command, all available interfaces (not explicitly attached to another area) are attached to area 0.

Example: Complex Internal Router with ABR and ASBR

The following example outlines a configuration for several routers within a single OSPF autonomous system. The figure below provides a general network map that illustrates this sample configuration.

Sample OSPF Autonomous System Network Map

In this configuration, five routers are configured with OSPF:

- Router A and Router B are both internal routers within area 1.

- Router C is an OSPF ABR. Note that for Router C, Area 1 is assigned to E3 and area 0 is assigned to S0.

- Router D is an internal router in area 0 (backbone area). In this case, both network router configuration commands specify the same area (area 0, or the backbone area).

- Router E is an OSPF ASBR. Note that BGP routes are redistributed into OSPF and that these routes are advertised by OSPF.

Note

You do not need to include definitions of all areas in an OSPF autonomous system in the configuration of all routers in the autonomous system. Only the directly connected areas must be defined. In the example that follows, routes in area 0 are learned by the routers in area 1 (Router A and Router B) when the ABR (Router C) injects summary LSAs into area 1.

The OSPF domain in BGP autonomous system 109 is connected to the outside world via the BGP link to the external peer at IP address 10.0.0.6. Sample configurations follow.

Following is the sample configuration for the general network map shown in the figure above.

Router A Configuration—Internal Router

interface ethernet 1
ip address 192.168.1.1 255.255.255.0
router ospf 1
network 192.168.0.0 0.0.255.255 area 1

Router B Configuration—Internal Router

interface ethernet 2
ip address 192.168.1.2 255.255.255.0
router ospf 202
network 192.168.0.0 0.0.255.255 area 1

Router C Configuration—ABR

interface ethernet 3
ip address 192.168.1.3 255.255.255.0
interface serial 0
ip address 192.168.2.3 255.255.255.0
router ospf 999
network 192.168.1.0 0.0.0.255 area 1
network 192.168.2.0 0.0.0.255 area 0

Router D Configuration—Internal Router

interface ethernet 4
ip address 10.0.0.4 255.0.0.0
interface serial 1
ip address 192.168.2.4 255.255.255.0
router ospf 50
network 192.168.2.0 0.0.0.255 area 0
network 10.0.0.0 0.255.255.255 area 0

Router E Configuration—ASBR

interface ethernet 5
ip address 10.0.0.5 255.0.0.0
interface serial 2
ip address 172.16.1.5 255.255.255.0
router ospf 65001
network 10.0.0.0 0.255.255.255 area 0
redistribute bgp 109 metric 1 metric-type 1
router bgp 109
network 192.168.0.0
network 10.0.0.0
neighbor 172.16.1.6 remote-as 110

Example: Complex OSPF Configuration for ABR

The following sample configuration accomplishes several tasks in setting up an ABR. These tasks can be split into two general categories:

- Basic OSPF configuration

- Route redistribution

The specific tasks outlined in this configuration are detailed briefly in the following descriptions. The figure below illustrates the network address ranges and area assignments for the interfaces.

Interface and Area Specifications for OSPF Sample Configuration

The basic configuration tasks in this example are as follows:

- Configure address ranges for Ethernet interface 0 through Ethernet interface 3.

- Enable OSPF on each interface.

- Set up an OSPF authentication password for each area and network.

- Assign link-state metrics and other OSPF interface configuration options.

- Create a stub area with area ID 36.0.0.0. (Note that the authentication and stub options of the area router configuration command are specified with separate area command entries, but can be merged into a single area command.)

- Specify the backbone area (area 0).

Configuration tasks associated with redistribution are as follows:

- Redistribute IGRP and RIP into OSPF with various options set (including including metric-type, metric, tag, and subnet).

- Redistribute IGRP and OSPF into RIP.

The following is a sample OSPF configuration:

interface ethernet 0
ip address 192.0.2.201 255.255.255.0
ip ospf authentication-key abcdefgh
ip ospf cost 10
!
interface ethernet 1
ip address 172.19.251.202 255.255.255.0
ip ospf authentication-key ijklmnop
ip ospf cost 20
ip ospf retransmit-interval 10
ip ospf transmit-delay 2
ip ospf priority 4
!
interface ethernet 2
ip address 172.19.254.2 255.255.255.0
ip ospf authentication-key abcdefgh
ip ospf cost 10
!
interface ethernet 3
ip address 10.56.0.0 255.255.0.0
ip ospf authentication-key ijklmnop
ip ospf cost 20
ip ospf dead-interval 80

In the following configuration, OSPF is on network 172.16.0.0:

router ospf 201
network 10.10.0.0 0.255.255.255 area 10.10.0.0
network 192.42.110.0 0.0.0.255 area 192.42.110.0
network 172.16.0.0 0.0.255.255 area 0
area 0 authentication
area 10.10.0.0 stub
area 10.10.0.0 authentication
area 10.10.0.0 default-cost 20
area 192.42.110.0 authentication
area 10.10.0.0 range 10.10.0.0 255.0.0.0
area 192.42.110.0 range 192.42.110.0 255.255.255.0
area 0 range 172.16.251.0 255.255.255.0
area 0 range 172.16.254.0 255.255.255.0
redistribute igrp 200 metric-type 2 metric 1 tag 200 subnets
redistribute rip metric-type 2 metric 1 tag 200

In the following configuration, IGRP autonomous system 200 is on 192.0.2.1:

router igrp 200
network 172.31.0.0
!
! RIP for 192.168.110
!
router rip
network 192.168.110.0
redistribute igrp 200 metric 1
redistribute ospf 201 metric 1

Examples: Route Map

The examples in this section illustrate the use of redistribution, with and without route maps. Examples from the IP and Connectionless Network Service (CLNS) routing protocols are given.

The following example redistributes all OSPF routes into IGRP:

router igrp 109
redistribute ospf 110

The following example redistributes RIP routes with a hop count equal to 1 into OSPF. These routes will be redistributed into OSPF as external LSAs with a metric of 5, a metric type of Type 1, and a tag equal to 1.

router ospf 109
redistribute rip route-map rip-to-ospf
!
route-map rip-to-ospf permit
match metric 1
set metric 5
set metric-type type1
set tag 1

The following example redistributes OSPF learned routes with tag 7 as a RIP metric of 15:

router rip
redistribute ospf 109 route-map 5
!
route-map 5 permit
match tag 7
set metric 15

The following example redistributes OSPF intra-area and interarea routes with next-hop routers on serial interface 0 into BGP with an INTER_AS metric of 5:

router bgp 109
redistribute ospf 109 route-map 10
!
route-map 10 permit
match route-type internal
match interface serial 0
set metric 5

The following example redistributes two types of routes into the integrated IS-IS routing table (supporting both IP and CLNS). The first type is OSPF external IP routes with tag 5; these routes are inserted into Level 2 IS-IS link state packets (LSPs) with a metric of 5. The second type is ISO-IGRP derived CLNS prefix routes that match CLNS access list 2000; these routes will be redistributed into IS-IS as Level 2 LSPs with a metric of 30.

router isis
redistribute ospf 109 route-map 2
redistribute iso-igrp nsfnet route-map 3
!
route-map 2 permit
match route-type external
match tag 5
set metric 5
set level level-2
!
route-map 3 permit
match address 2000
set metric 30

With the following configuration, OSPF external routes with tags 1, 2, 3, and 5 are redistributed into RIP with metrics of 1, 1, 5, and 5, respectively. The OSPF routes with a tag of 4 are not redistributed.

router rip
redistribute ospf 109 route-map 1
!
route-map 1 permit
match tag 1 2
set metric 1
!
route-map 1 permit
match tag 3
set metric 5
!
route-map 1 deny
match tag 4
!
route map 1 permit
match tag 5
set metric 5

In the following configuration, a RIP-learned route for network 192.168.0.0 and an ISO-IGRP-learned route with prefix 49.0001.0002 are redistributed into an IS-IS Level 2 LSP with a metric of 5:

router isis
redistribute rip route-map 1
redistribute iso-igrp remote route-map 1
!
route-map 1 permit
match ip address 1
match clns address 2
set metric 5
set level level-2
!
access-list 1 permit 192.168.0.0 0.0.255.255
clns filter-set 2 permit 49.0001.0002...

The following configuration example illustrates how a route map is referenced by the default-information router configuration command. This type of reference is called conditional default origination. OSPF will originate the default route (network 0.0.0.0) with a Type 2 metric of 5 if 172.16.0.0 is in the routing table.

Note

Only routes external to the OSPF process can be used for tracking, such as non-OSPF routes or OSPF routes from a separate OSPF process.

route-map ospf-default permit
match ip address 1
set metric 5
set metric-type type-2
!
access-list 1 permit 172.16.0.0 0.0.255.255
!
router ospf 109
default-information originate route-map ospf-default

Example: Changing the OSPF Administrative Distances

The following configuration changes the external distance to 200, making it less trustworthy. The figure below illustrates the example.

OSPF Administrative Distance

Router A Configuration

router ospf 1
redistribute ospf 2 subnet
distance ospf external 200
!
router ospf 2
redistribute ospf 1 subnet
distance ospf external 200

Router B Configuration

router ospf 1
redistribute ospf 2 subnet
distance ospf external 200
!
router ospf 2
redistribute ospf 1 subnet
distance ospf external 200

Example: OSPF over On-Demand Routing

The following configuration allows OSPF over an on-demand circuit, as shown in the figure below. Note that the on-demand circuit is defined on one side only (BRI 0 on Router A); it is not required to be configured on both sides.

OSPF over On-Demand Circuit

Router A Configuration

username RouterB password 7 060C1A2F47
isdn switch-type basic-5ess
ip routing
!
interface TokenRing0
ip address 192.168.50.5 255.255.255.0
no shutdown
!
interface BRI0
no cdp enable
description connected PBX 1485
ip address 192.168.45.30 255.255.255.0
encapsulation ppp
ip ospf demand-circuit
dialer map ip 192.0.2.6 name RouterB broadcast 61484
dialer-group 1
ppp authentication chap
no shutdown
!
router ospf 100
network 192.168.45.0 0.0.0.255 area 0
network 192.168.45.50 0.0.0.255 area 0
!
dialer-list 1 protocol ip permit

Router B Configuration

username RouterA password 7 04511E0804
isdn switch-type basic-5ess
ip routing
!
interface Ethernet0
ip address 192.168.50.16 255.255.255.0
no shutdown
!
interface BRI0
no cdp enable
description connected PBX 1484
ip address  192.168.45.17 255.255.255.0
encapsulation ppp
dialer map ip 192.168.45.19 name RouterA broadcast 61485
dialer-group 1
ppp authentication chap
no shutdown
!
router ospf 100
network 192.168.45.0 0.0.0.255 area 0
network 192.168.45.50 0.0.0.255 area 0
!
dialer-list 1 protocol ip permit

Example: LSA Group Pacing

The following example changes the OSPF pacing between LSA groups to 60 seconds:

router ospf
timers pacing lsa-group 60

Example: Blocking OSPF LSA Flooding

The following example prevents flooding of OSPF LSAs to broadcast, nonbroadcast, or point-to-point networks reachable through Ethernet interface 0:

interface ethernet 0
ip ospf database-filter all out

The following example prevents flooding of OSPF LSAs to point-to-multipoint networks to the neighbor at IP address 10.10.10.45:

router ospf 109
neighbor 10.10.10.45 database-filter all out

Example: Ignoring MOSPF LSA Packets

The following example configures the router to suppress the sending of syslog messages when it receives MOSPF packets:

router ospf 109
ignore lsa mospf

Additional References for OSPF Not-So-Stubby Areas (NSSA)

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Protocol-independent features that work with OSPF

“Configuring IP Routing Protocol-Independent Features” module in IP Routing: Protocol-Independent Configuration Guide

RFCs

RFC

Title

RFC 1587

The OSPF NSSA Option, March 1994

RFC 3101

The OSPF NSSA Option January 2003

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for Configuring OSPF

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF

Feature Name

Releases

Feature Information

OSPF

OSPF is an IGP developed by the OSPF working group of the IETF. Designed expressly for IP networks, OSPF supports IP subnetting and tagging of externally derived routing information. OSPF also allows packet authentication and uses IP multicast when sending and receiving packets.

OSPF

11.2(1)

OSPF is an IGP developed by the OSPF working group of the IETF. Designed expressly for IP networks, OSPF supports IP subnetting and tagging of externally derived routing information. OSPF also allows packet authentication and uses IP multicast when sending and receiving packets.

OSPF Flooding Reduction

12.1(2)T

The OSPF flooding reduction solution works by reducing unnecessary refreshing and flooding of already known and unchanged information.

OSPF Not-So-Stubby Areas

11.2(1)

OSPF NSSA is a nonproprietary extension of the existing OSPF stub area feature.

OSPF Packet Pacing

12.0(1)T

OSPF update packets are automatically paced so they are not sent less than 33 milliseconds apart.

OSPF Support for NSSA RFC 3101

15.2(2)T

This feature adds support for the OSPF NSSA specification described by RFC 3101. RFC3101 replaced RFC 1587 and is backward compatible with RFC1587.

The following commands were introduced or modified: area nssa translate, compatible rfc1587.

OSPFv3 RFC 3101 Support

Cisco IOS Release 15.3(1)T

The area nssa translate (OSPFv3), compatible rfc1587 (OSPFv3), and show ospfv3 commands were added. The nssa-only keyword was added to the summary-prefix (OSPFv3) command.

Chapter 2. IPv6 Routing: OSPFv3

Open Shortest Path First version 3 (OSPFv3) is an IPv4 and IPv6 link-state routing protocol that supports IPv6 and IPv4 unicast address families (AFs).

- Finding Feature Information

- Prerequisites for IPv6 Routing: OSPFv3

- Restrictions for IPv6 Routing: OSPFv3

- Information About IPv6 Routing: OSPFv3

- How to Configure Load Balancing in OSPFv3

- Configuration Examples for Load Balancing in OSPFv3

- Additional References

- Feature Information for IPv6 Routing: OSPFv3

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for IPv6 Routing: OSPFv3

- Complete the OSPFv3 network strategy and planning for your IPv6 network. For example, you must decide whether multiple areas are required.

- Enable IPv6 unicast routing.

- Enable IPv6 on the interface.

Restrictions for IPv6 Routing: OSPFv3

When running a dual-stack IP network with OSPF version 2 for IPv4 and OSPFv3, be careful when changing the defaults for commands used to enable OSPFv3. Changing these defaults may affect your OSPFv3 network, possibly adversely.

Information About IPv6 Routing: OSPFv3

- How OSPFv3 Works

- Comparison of OSPFv3 and OSPF Version 2

- LSA Types for OSPFv3

- NBMA in OSPFv3

- Load Balancing in OSPFv3

- Addresses Imported into OSPFv3

- OSPFv3 Customization

- Force SPF in OSPFv3

How OSPFv3 Works

OSPFv3 is a routing protocol for IPv4 and IPv6. It is a link-state protocol, as opposed to a distance-vector protocol. Think of a link as being an interface on a networking device. A link-state protocol makes its routing decisions based on the states of the links that connect source and destination machines. The state of a link is a description of that interface and its relationship to its neighboring networking devices. The interface information includes the IPv6 prefix of the interface, the network mask, the type of network it is connected to, the devices connected to that network, and so on. This information is propagated in various type of link-state advertisements (LSAs).

A device’s collection of LSA data is stored in a link-state database. The contents of the database, when subjected to the Dijkstra algorithm, result in the creation of the OSPF routing table. The difference between the database and the routing table is that the database contains a complete collection of raw data; the routing table contains a list of shortest paths to known destinations via specific device interface ports.

OSPFv3, which is described in RFC 5340, supports IPv6 and IPv4 unicast AFs.

Comparison of OSPFv3 and OSPF Version 2

Much of OSPF version 3 is the same as in OSPF version 2. OSPFv3, which is described in RFC 5340, expands on OSPF version 2 to provide support for IPv6 routing prefixes and the larger size of IPv6 addresses.

In OSPFv3, a routing process does not need to be explicitly created. Enabling OSPFv3 on an interface will cause a routing process, and its associated configuration, to be created.

In OSPFv3, each interface must be enabled using commands in interface configuration mode. This feature is different from OSPF version 2, in which interfaces are indirectly enabled using the device configuration mode.

When using a nonbroadcast multiaccess (NBMA) interface in OSPFv3, you must manually configure the device with the list of neighbors. Neighboring devices are identified by their device ID.

In IPv6, you can configure many address prefixes on an interface. In OSPFv3, all address prefixes on an interface are included by default. You cannot select some address prefixes to be imported into OSPFv3; either all address prefixes on an interface are imported, or no address prefixes on an interface are imported.

Unlike OSPF version 2, multiple instances of OSPFv3 can be run on a link.

OSPF automatically prefers a loopback interface over any other kind, and it chooses the highest IP address among all loopback interfaces. If no loopback interfaces are present, the highest IP address in the device is chosen. You cannot tell OSPF to use any particular interface.

LSA Types for OSPFv3

The following list describes LSA types, each of which has a different purpose:

- Device LSAs (Type 1)—Describes the link state and costs of a device’s links to the area. These LSAs are flooded within an area only. The LSA indicates if the device is an Area Border Router (ABR) or Autonomous System Boundary Router (ASBR), and if it is one end of a virtual link. Type 1 LSAs are also used to advertise stub networks. In OSPFv3, these LSAs have no address information and are network-protocol-independent. In OSPFv3, device interface information may be spread across multiple device LSAs. Receivers must concatenate all device LSAs originated by a given device when running the SPF calculation.

- Network LSAs (Type 2)—Describes the link-state and cost information for all devices attached to the network. This LSA is an aggregation of all the link-state and cost information in the network. Only a designated device tracks this information and can generate a network LSA. In OSPFv3, network LSAs have no address information and are network-protocol-independent.

- Interarea-prefix LSAs for ABRs (Type 3)—Advertises internal networks to devices in other areas (interarea routes). Type 3 LSAs may represent a single network or a set of networks summarized into one advertisement. Only ABRs generate summary LSAs. In OSPFv3, addresses for these LSAs are expressed as prefix, prefix length instead of address, mask. The default route is expressed as a prefix with length 0.

- Interarea-device LSAs for ASBRs (Type 4)—Advertises the location of an ASBR. Devices that are trying to reach an external network use these advertisements to determine the best path to the next hop. Type 4 LSAs are generated by ABRs on behalf of ASBRs.

- Autonomous system external LSAs (Type 5)—Redistributes routes from another autonomous system, usually from a different routing protocol into OSPFv3. In OSPFv3, addresses for these LSAs are expressed as prefix, prefix length instead of address, mask. The default route is expressed as a prefix with length 0.

- Link LSAs (Type 8)—Have local-link flooding scope and are never flooded beyond the link with which they are associated. Link LSAs provide the link-local address of the device to all other devices attached to the link, inform other devices attached to the link of a list of prefixes to associate with the link, and allow the device to assert a collection of Options bits to associate with the network LSA that will be originated for the link.

- Intra-Area-Prefix LSAs (Type 9)—A device can originate multiple intra-area-prefix LSAs for each device or transit network, each with a unique link-state ID. The link-state ID for each intra-area-prefix LSA describes its association to either the device LSA or the network LSA and contains prefixes for stub and transit networks.

An address prefix occurs in almost all newly defined LSAs. The prefix is represented by three fields: PrefixLength, PrefixOptions, and Address Prefix. In OSPFv3, addresses for these LSAs are expressed as prefix, prefix length instead of address, mask. The default route is expressed as a prefix with length 0. Type 3 and Type 9 LSAs carry all prefix (subnet) information that, in OSPFv2, is included in device LSAs and network LSAs. The Options field in certain LSAs (device LSAs, network LSAs, interarea-device LSAs, and link LSAs) has been expanded to 24 bits to provide support for OSPFv3.

In OSPFv3, the sole function of the link-state ID in interarea-prefix LSAs, interarea-device LSAs, and autonomous-system external LSAs is to identify individual pieces of the link-state database. All addresses or device IDs that are expressed by the link-state ID in OSPF version 2 are carried in the body of the LSA in OSPFv3.

The link-state ID in network LSAs and link LSAs is always the interface ID of the originating device on the link being described. For this reason, network LSAs and link LSAs are now the only LSAs whose size cannot be limited. A network LSA must list all devices connected to the link, and a link LSA must list all of the address prefixes of a device on the link.

NBMA in OSPFv3

On NBMA networks, the designated router (DR) or backup DR (BDR) performs the LSA flooding. On point-to-point networks, flooding simply goes out an interface directly to a neighbor.

Devices that share a common segment (Layer 2 link between two interfaces) become neighbors on that segment. OSPFv3 uses the Hello protocol, periodically sending hello packets out each interface. Devices become neighbors when they see themselves listed in the neighbor’s hello packet. After two devices become neighbors, they may proceed to exchange and synchronize their databases, which creates an adjacency. Not all neighboring devices have an adjacency.

On point-to-point and point-to-multipoint networks, the software floods routing updates to immediate neighbors. There is no DR or BDR; all routing information is flooded to each networking device.

On broadcast or NBMA segments only, OSPFv3 minimizes the amount of information being exchanged on a segment by choosing one device to be a DR and one device to be a BDR. Thus, the devices on the segment have a central point of contact for information exchange. Instead of each device exchanging routing updates with every other device on the segment, each device exchanges information with the DR and BDR. The DR and BDR relay the information to the other devices.

The software looks at the priority of the devices on the segment to determine which devices will be the DR and BDR. The device with the highest priority is elected the DR. If there is a tie, then the device with the higher device ID takes precedence. After the DR is elected, the BDR is elected the same way. A device with a device priority set to zero is ineligible to become the DR or BDR.

When using NBMA in OSPFv3, you cannot automatically detect neighbors. On an NBMA interface, you must configure your neighbors manually using interface configuration mode.

Load Balancing in OSPFv3

When a device learns multiple routes to a specific network via multiple routing processes (or routing protocols), it installs the route with the lowest administrative distance in the routing table. Sometimes the device must select a route from among many learned via the same routing process with the same administrative distance. In this case, the device chooses the path with the lowest cost (or metric) to the destination. Each routing process calculates its cost differently and the costs may need to be manipulated in order to achieve load balancing.

OSPFv3 performs load balancing automatically in the following way. If OSPFv3 finds that it can reach a destination through more than one interface and each path has the same cost, it installs each path in the routing table. The only restriction on the number of paths to the same destination is controlled by the maximum-paths command. The default maximum paths is 16, and the range is from 1 to 64.

Addresses Imported into OSPFv3

When importing the set of addresses specified on an interface on which OSPFv3 is running into OSPFv3, you cannot select specific addresses to be imported. Either all addresses are imported, or no addresses are imported.

OSPFv3 Customization

You can customize OSPFv3 for your network, but you likely will not need to do so. The defaults for OSPFv3 are set to meet the requirements of most customers and features. If you must change the defaults, refer to the IPv6 command reference to find the appropriate syntax.

Caution

Be careful when changing the defaults. Changing defaults will affect your OSPFv3 network, possibly adversely.

- OSPFv3 Cost Calculation

OSPFv3 Cost Calculation

Because cost components can change rapidly, it might be necessary to reduce the volume of changes to reduce network-wide churn. The recommended values for S2, S3, and S4 in the second table below are based on network simulations that may reduce the rate of network changes. The recommended value for S1 is 0 to eliminate this variable from the route cost calculation.

The overall link cost is computed using the formula shown in the figure below.

Overall Link Cost Formula

The table below defines the symbols used in the OSPFv3 cost calculation.

OSPFv3 Cost Calculation Definitions

Cost Component

Component Definition

OC

The default OSPFv3 cost. Calculated from reference bandwidth using reference_bw / (MDR*1000), where reference_bw=10^8.

A through D

Various radio-specific data-based formulas that produce results in the 0 through 64,000 range.

A

CDR- and MDR-related formula:

(2^16 * (100 – (CDR * 100 / MDR)))/100

B

Resources related formula:

((100 – RESOURCES)^3 * 2^16 / 10^6)

C

Latency as reported by the radio, already in the 0 through 64,000 range when reported (LATENCY).

D

RLF-related formula:

((100 – RLF) * 2^16)/100

S1 through S4

Scalar weighting factors input from the CLI. These scalars scale down the values as computed by A through D.

The value of 0 disables and the value of 100 enables full 0 through 64,000 range for one component.

Because each network might have unique characteristics that require different settings to optimize actual network performance, these are recommended values intended as a starting point for optimizing an OSPFv3 network. The table below lists the recommended value settings for OSPFv3 cost metrics.

Recommended Value Settings for OSPFv3 Cost Metrics

Setting

Metric Description

Default Value

Recommended Value

S1

ipv6 ospf dynamic weight throughout

100

0

S2

ipv6 ospf dynamic weight resources

100

29

S3

ipv6 ospf dynamic weight latency

100

29

S4

ipv6 ospf dynamic weight L2 factor

100

29

The default path costs were calculated using this formula, as noted in the following list. If these values do not suit your network, you can use your own method of calculating path costs.

- 56-kbps serial link—Default cost is 1785.

- 64-kbps serial link—Default cost is 1562.

- T1 (1.544-Mbps serial link)—Default cost is 64.

- E1 (2.048-Mbps serial link)—Default cost is 48.

- 4-Mbps Token Ring—Default cost is 25.

- Ethernet—Default cost is 10.

- 16-Mbps Token Ring—Default cost is 6.

- FDDI—Default cost is 1.

- X25—Default cost is 5208.

- Asynchronous—Default cost is 10,000.

- ATM—Default cost is 1.

To illustrate these settings, the following example shows how OSPFv3 cost metrics might be defined for a Virtual Multipoint Interface (VMI) interface:

interface vmi1
ipv6 ospf cost dynamic weight throughput 0
ipv6 ospf cost dynamic weight resources 29
ipv6 ospf cost dynamic weight latency 29
ipv6 ospf cost dynamic weight L2-factor 29

Force SPF in OSPFv3

When the process keyword is used with the clear ipv6 ospf command, the OSPFv3 database is cleared and repopulated, and then the SPF algorithm is performed. When the force-spf keyword is used with the clear ipv6 ospf command, the OSPFv3 database is not cleared before the SPF algorithm is performed.

How to Configure Load Balancing in OSPFv3

- Configuring the OSPFv3 Device Process

- Configuring NBMA Interfaces in OSPFv3

- Forcing an SPF Calculation

- Verifying OSPFv3 Configuration and Operation

Configuring the OSPFv3 Device Process

Once you have completed step 3 and entered OSPFv3 router configuration mode, you can perform any of the subsequent steps in this task as needed to configure OSPFv3 Device configuration.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    area area-ID [default-cost | nssa | stub]

5.    auto-cost reference-bandwidth Mbps

6.    default {area area-ID [range ipv6-prefix | virtual-link router-id]} [default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv6-prefix]

7.    ignore lsa mospf

8.    interface-id snmp-if-index

9.    log-adjacency-changes [detail]

10.    passive-interface [default | interface-type interface-number]

11.    queue-depth {hello | update} {queue-size | unlimited}

12.    router-id router-id

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enters router configuration mode for the IPv4 or IPv6 address family.

Step 4

area area-ID [default-cost | nssa | stub]

Example:

Device(config-router)# area 1

Configures the OSPFv3 area.

Step 5

auto-cost reference-bandwidth Mbps

Example:

Device(config-router)# auto-cost reference-bandwidth 1000

Controls the reference value OSPFv3 uses when calculating metrics for interfaces in an IPv4 OSPFv3 process.

Step 6

default {area area-ID [range ipv6-prefix | virtual-link router-id]} [default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv6-prefix]

Example:

Device(config-router)# default area 1

Returns an OSPFv3 parameter to its default value.

Step 7

ignore lsa mospf

Example:

Device(config-router)# ignore lsa mospf

Suppresses the sending of syslog messages when the device receives LSA Type 6 multicast OSPFv3 packets, which are unsupported.

Step 8

interface-id snmp-if-index

Example:

Device(config-router)# interface-id snmp-if-index

Configures OSPFv3 interfaces with Simple Network Management Protocol (SNMP) MIB-II interface Index (ifIndex) identification numbers in IPv4 and IPv6.

Step 9

log-adjacency-changes [detail]

Example:

Device(config-router)# log-adjacency-changes

Configures the device to send a syslog message when an OSPFv3 neighbor goes up or down.

Step 10

passive-interface [default | interface-type interface-number]

Example:

Device(config-router)# passive-interface default

Suppresses sending routing updates on an interface when an IPv4 OSPFv3 process is used.

Step 11

queue-depth {hello | update} {queue-size | unlimited}

Example:

Device(config-router)# queue-depth update 1500

Configures the number of incoming packets that the IPv4 OSPFv3 process can keep in its queue.

Step 12

router-id router-id

Example:

Device(config-router)# router-id 10.1.1.1

Enter this command to use a fixed router ID.

Configuring NBMA Interfaces in OSPFv3

You can customize OSPFv3 in your network to use NBMA interfaces. OSPFv3 cannot automatically detect neighbors over NBMA interfaces. On an NBMA interface, you must configure your neighbors manually using interface configuration mode.

Before You Begin

Before you configure NBMA interfaces, you must perform the following tasks:

- Configure your network to be an NBMA network

- Identify each neighbor

Note

- You cannot automatically detect neighbors when using NBMA interfaces. You must manually configure your device to detect neighbors when using an NBMA interface.

- When the ipv6 ospf neighbor command is configured, the IPv6 address used must be the link-local address of the neighbor.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ipv6 enable

5.    ipv6 ospf neighbor ipv6-address [priority number] [poll-interval seconds] [cost number] [database-filter all out]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Specifies an interface type and number, and places the device in interface configuration mode.

Step 4

ipv6 enable

Example:

Device (config-if)#ipv6 enable

Enables ipv6 on an interface.

Step 5

ipv6 ospf neighbor ipv6-address [priority number] [poll-interval seconds] [cost number] [database-filter all out]

Example:

Device(config-if) ipv6 ospf neighbor FE80::A8BB:CCFF:FE00:C01

Configures an OSPFv3 neighboring device.

Forcing an SPF Calculation

SUMMARY STEPS

1.    enable

2.    clear ospfv3 [process-id] force-spf

3.    clear ospfv3 [process-id] process

4.    clear ospfv3 [process-id] redistribution

5.    clear ipv6 ospf [process-id] {process | force-spf | redistribution}

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

clear ospfv3 [process-id] force-spf

Example:

Device# clear ospfv3 1 force-spf

Runs SPF calculations for an OSPFv3 process.

- If the clear ospfv3 force-spf command is configured, it overwrites the clear ipv6 ospf configuration.

- Once the clear ospfv3 force-spf command has been used, the clear ipv6 ospf command cannot be used.

Step 3

clear ospfv3 [process-id] process

Example:

Device# clear ospfv3 2 process

Resets an OSPFv3 process.

- If the clear ospfv3 force-spf command is configured, it overwrites the clear ipv6 ospf configuration.

- Once the clear ospfv3 force-spf command has been used, the clear ipv6 ospf command cannot be used.

Step 4

clear ospfv3 [process-id] redistribution

Example:

Device# clear ospfv3 redistribution

Clears OSPFv3 route redistribution.

- If the clear ospfv3 force-spf command is configured, it overwrites the clear ipv6 ospf configuration.

- Once the clear ospfv3 force-spf command has been used, the clear ipv6 ospf command cannot be used.

Step 5

clear ipv6 ospf [process-id] {process | force-spf | redistribution}

Example:

Device# clear ipv6 ospf force-spf

Clears the OSPFv3 state based on the OSPFv3 routing process ID, and forces the start of the SPF algorithm.

- If the clear ospfv3 force-spf command is configured, it overwrites the clear ipv6 ospf configuration.

- Once the clear ospfv3 force-spf command has been used, the clear ipv6 ospf command cannot be used.

Verifying OSPFv3 Configuration and Operation

This task is optional, and the commands can be entered in any order, as needed.

SUMMARY STEPS

1.    enable

2.    show ospfv3 [process-id] [address-family] border-routers

3.    show ospfv3 [process-id [area-id]] [address-family] database [database-summary | internal | external [ipv6-prefix ] [link-state-id] | grace | inter-area prefix [ipv6-prefix | link-state-id] | inter-area router [destination-router-id | link-state-id] | link [interface interface-name | link-state-id] | network [link-state-id] | nssa-external [ipv6-prefix] [link-state-id] | prefix [ref-lsa {router | network} | link-state-id] | promiscuous | router [link-state-id] | unknown [{area | as | link} [link-state-id]] [adv-router router-id] [self-originate]

4.    show ospfv3 [process-id] [address-family] events [generic | interface | lsa | neighbor | reverse | rib | spf]

5.    show ospfv3 [process-id] [area-id] [address-family] flood-list interface-type interface-number

6.    show ospfv3 [process-id] [address-family] graceful-restart

7.    show ospfv3 [process-id] [area-id] [address-family] interface [type number] [brief]

8.    show ospfv3 [process-id] [area-id] [address-family] neighbor [interface-type interface-number] [neighbor-id] [detail]

9.    show ospfv3 [process-id] [area-id] [address-family] request-list[neighbor] [interface] [interface-neighbor]

10.    show ospfv3 [process-id] [area-id] [address-family] retransmission-list [neighbor] [interface] [interface-neighbor]

11.    show ospfv3 [process-id] [address-family] statistic [detail]

12.    show ospfv3 [process-id] [address-family] summary-prefix

13.    show ospfv3 [process-id] [address-family] timers rate-limit

14.    show ospfv3 [process-id] [address-family] traffic[interface-type interface-number]

15.    show ospfv3 [process-id] [address-family] virtual-links

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ospfv3 [process-id] [address-family] border-routers

Example:

Device# show ospfv3 border-routers

Displays the internal OSPFv3 routing table entries to an ABR and ASBR.

Step 3

show ospfv3 [process-id [area-id]] [address-family] database [database-summary | internal | external [ipv6-prefix ] [link-state-id] | grace | inter-area prefix [ipv6-prefix | link-state-id] | inter-area router [destination-router-id | link-state-id] | link [interface interface-name | link-state-id] | network [link-state-id] | nssa-external [ipv6-prefix] [link-state-id] | prefix [ref-lsa {router | network} | link-state-id] | promiscuous | router [link-state-id] | unknown [{area | as | link} [link-state-id]] [adv-router router-id] [self-originate]

Example:

Device# show ospfv3 database

Displays lists of information related to the OSPFv3 database for a specific device.

Step 4

show ospfv3 [process-id] [address-family] events [generic | interface | lsa | neighbor | reverse | rib | spf]

Example:

Device# show ospfv3 events

Displays detailed information about OSPFv3 events.

Step 5

show ospfv3 [process-id] [area-id] [address-family] flood-list interface-type interface-number

Example:

Device# show ospfv3 flood-list

Displays a list of OSPFv3 LSAs waiting to be flooded over an interface.

Step 6

show ospfv3 [process-id] [address-family] graceful-restart

Example:

Device# show ospfv3 graceful-restart

Displays OSPFv3 graceful restart information.

Step 7

show ospfv3 [process-id] [area-id] [address-family] interface [type number] [brief]

Example:

Device# show ospfv3 interface

Displays OSPFv3-related interface information.

Step 8

show ospfv3 [process-id] [area-id] [address-family] neighbor [interface-type interface-number] [neighbor-id] [detail]

Example:

Device# show ospfv3 neighbor

Displays OSPFv3 neighbor information on a per-interface basis.

Step 9

show ospfv3 [process-id] [area-id] [address-family] request-list[neighbor] [interface] [interface-neighbor]

Example:

Device# show ospfv3 request-list

Displays a list of all LSAs requested by a device.

Step 10

show ospfv3 [process-id] [area-id] [address-family] retransmission-list [neighbor] [interface] [interface-neighbor]

Example:

Device# show ospfv3 retransmission-list

Displays a list of all LSAs waiting to be re-sent.

Step 11

show ospfv3 [process-id] [address-family] statistic [detail]

Example:

Device# show ospfv3 statistic

Displays OSPFv3 SPF calculation statistics.

Step 12

show ospfv3 [process-id] [address-family] summary-prefix

Example:

Device# show ospfv3 summary-prefix

Displays a list of all summary address redistribution information configured under an OSPFv3 process.

Step 13

show ospfv3 [process-id] [address-family] timers rate-limit

Example:

Device# show ospfv3 timers rate-limit

Displays all of the LSAs in the rate limit queue.

Step 14

show ospfv3 [process-id] [address-family] traffic[interface-type interface-number]

Example:

Device# show ospfv3 traffic

Displays OSPFv3 traffic statistics.

Step 15

show ospfv3 [process-id] [address-family] virtual-links

Example:

Device# show ospfv3 virtual-links

Displays parameters and the current state of OSPFv3 virtual links.

Configuration Examples for Load Balancing in OSPFv3

- Example: Configuring the OSPFv3 Device Process

- Example: Configuring NBMA Interfaces

- Example: Forcing SPF Configuration

Example: Configuring the OSPFv3 Device Process

Device# show ospfv3 database
OSPFv3 Device with ID (172.16.4.4) (Process ID 1)
Device Link States (Area 0)
ADV Device         Age         Seq#        Fragment ID   Link count  Bits
172.16.4.4         239         0x80000003  0             1           B
172.16.6.6         239         0x80000003  0             1           B
Inter Area Prefix Link States (Area 0)
ADV Device         Age         Seq#        Prefix
172.16.4.4         249         0x80000001  FEC0:3344::/32
172.16.4.4         219         0x80000001  FEC0:3366::/32
172.16.6.6         247         0x80000001  FEC0:3366::/32
172.16.6.6         193         0x80000001  FEC0:3344::/32
172.16.6.6         82          0x80000001  FEC0::/32
Inter Area Device Link States (Area 0)
ADV Device         Age         Seq#        Link ID    Dest DevID
172.16.4.4         219         0x80000001  50529027   172.16.3.3
172.16.6.6         193         0x80000001  50529027   172.16.3.3

Link (Type-8) Link States (Area 0)
ADV Device         Age         Seq#        Link ID    Interface
172.16.4.4         242         0x80000002  14         PO4/0
172.16.6.6         252         0x80000002  14         PO4/0
Intra Area Prefix Link States (Area 0)
ADV Device         Age         Seq#        Link ID    Ref-lstype  Ref-LSID
172.16.4.4         242         0x80000002  0          0x2001      0
172.16.6.6         252         0x80000002  0          0x2001      0

Device# show ospfv3 neighbor

OSPFv3 Device with ID (10.1.1.1) (Process ID 42)
Neighbor ID     Pri   State           Dead Time   Interface ID    Interface
10.4.4.4        1    FULL/  -        00:00:39    12              vm1
OSPFv3 Device with ID (10.2.1.1) (Process ID 100)
Neighbor ID     Pri   State           Dead Time   Interface ID    Interface
10.5.4.4          1    FULL/  -        00:00:35    12              vm1

Example: Configuring NBMA Interfaces

The following example shows how to configure an OSPFv3 neighboring device with the IPv6 address of FE80::A8BB:CCFF:FE00:C01.

interface serial 0
ipv6 enable
ipv6 ospf 1 area 0
encapsulation frame-relay
frame-relay map ipv6 FE80::A8BB:CCFF:FE00:C01 120
ipv6 ospf neighbor FE80::A8BB:CCFF:FE00:C0

Example: Forcing SPF Configuration

The following example shows how to trigger SPF to redo the SPF and repopulate the routing tables:

clear ipv6 ospf force-spf

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

IPv6 Routing: OSPFv3

“Configuring OSPF” module

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for IPv6 Routing: OSPFv3

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for IPv6 Routing: OSPFv3

Feature Name

Releases

Feature Information

IPv6 Routing: OSPFv3

12.2(15)T

12.3

OSPF version 3 for IPv6 expands on OSPF version 2 to provide support for IPv6 routing prefixes and the larger size of IPv6 addresses.

OSPFv3 Dynamic Interface Cost Support

12.4(15)T

OSPFv3 dynamic interface cost support provides enhancements to the OSPFv3 cost metric for supporting mobile ad hoc networking.

Chapter 3. IPv6 Routing: OSPFv3 Authentication Support with IPsec

In order to ensure that Open Shortest Path First version 3 (OSPFv3) packets are not altered and re-sent to the device, OSPFv3 packets must be authenticated. OSPFv3 uses the IPsec secure socket API to add authentication to OSPFv3 packets. This API supports IPv6.

- Finding Feature Information

- Prerequisites for IPv6 Routing: OSPFv3 Authentication Support with IPsec

- Information About IPv6 Routing: OSPFv3 Authentication Support with IPsec

- How to Configure IPv6 Routing: OSPFv3 Authentication Support with IPsec

- Configuration Examples for IPv6 Routing: OSPFv3 Authentication Support with IPsec

- Additional References for IPv6 Routing: OSPFv3 Authentication Support with IPsec

- Feature Information for IPv6 Routing: OSPFv3 Authentication Support with IPsec

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for IPv6 Routing: OSPFv3 Authentication Support with IPsec

Configure the IP Security (IPsec) secure socket application program interface (API) on OSPFv3 in order to enable authentication and encryption.

Information About IPv6 Routing: OSPFv3 Authentication Support with IPsec

- OSPFv3 Authentication Support with IPsec

OSPFv3 Authentication Support with IPsec

In order to ensure that OSPFv3 packets are not altered and re-sent to the device, causing the device to behave in a way not desired by its system administrators, OSPFv3 packets must be authenticated. OSPFv3 uses the IPsec secure socket API to add authentication to OSPFv3 packets. This API supports IPv6.

OSPFv3 requires the use of IPsec to enable authentication. Crypto images are required to use authentication, because only crypto images include the IPsec API needed for use with OSPFv3.

In OSPFv3, authentication fields have been removed from OSPFv3 packet headers. When OSPFv3 runs on IPv6, OSPFv3 requires the IPv6 authentication header (AH) or IPv6 ESP header to ensure integrity, authentication, and confidentiality of routing exchanges. IPv6 AH and ESP extension headers can be used to provide authentication and confidentiality to OSPFv3.

To use the IPsec AH, you must enable the ipv6 ospf authentication command. To use the IPsec ESP header, you must enable the ipv6 ospf encryption command. The ESP header may be applied alone or in combination with the AH, and when ESP is used, both encryption and authentication are provided. Security services can be provided between a pair of communicating hosts, between a pair of communicating security gateways, or between a security gateway and a host.

To configure IPsec, you configure a security policy, which is a combination of the security policy index (SPI) and the key (the key is used to create and validate the hash value). IPsec for OSPFv3 can be configured on an interface or on an OSPFv3 area. For higher security, you should configure a different policy on each interface configured with IPsec. If you configure IPsec for an OSPFv3 area, the policy is applied to all of the interfaces in that area, except for the interfaces that have IPsec configured directly. Once IPsec is configured for OSPFv3, IPsec is invisible to you.

The secure socket API is used by applications to secure traffic. The API needs to allow the application to open, listen, and close secure sockets. The binding between the application and the secure socket layer also allows the secure socket layer to inform the application of changes to the socket, such as connection open and close events. The secure socket API is able to identify the socket; that is, it can identify the local and remote addresses, masks, ports, and protocol that carry the traffic requiring security.

Each interface has a secure socket state, which can be one of the following:

- NULL: Do not create a secure socket for the interface if authentication is configured for the area.

- DOWN: IPsec has been configured for the interface (or the area that contains the interface), but OSPFv3 either has not requested IPsec to create a secure socket for this interface, or there is an error condition.

- GOING UP: OSPFv3 has requested a secure socket from IPsec and is waiting for a CRYPTO_SS_SOCKET_UP message from IPsec.

- UP: OSPFv3 has received a CRYPTO_SS_SOCKET_UP message from IPsec.

- CLOSING: The secure socket for the interface has been closed. A new socket may be opened for the interface, in which case the current secure socket makes the transition to the DOWN state. Otherwise, the interface will become UNCONFIGURED.

- UNCONFIGURED: Authentication is not configured on the interface.

OSPFv3 will not send or accept packets while in the DOWN state.

How to Configure IPv6 Routing: OSPFv3 Authentication Support with IPsec

- Configuring IPsec on OSPFv3

Configuring IPsec on OSPFv3

Once you have configured OSPFv3 and decided on your authentication, you must define the security policy on each of the devices within the group. The security policy consists of the combination of the key and the SPI. To define a security policy, you must define an SPI and a key.

You can configure an authentication or encryption policy either on an interface or for an OSPFv3 area. When you configure for an area, the security policy is applied to all of the interfaces in the area. For higher security, use a different policy on each interface.

You can configure authentication and encryption on virtual links.

- Defining Authentication on an Interface

- Defining Authentication in an OSPFv3 Area

Defining Authentication on an Interface

Before You Begin

Before you configure IPsec on an interface, you must configure OSPFv3 on that interface.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    Do one of the following:

- ospfv3 authentication {ipsec spi} {md5 | sha1}{ key-encryption-type key} | null

- ipv6 ospf authentication {null | ipsec spi spi authentication-algorithm [key-encryption-type] [key]}

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface ethernet 0/0

Specifies an interface type and number, and places the device in interface configuration mode.

Note:
For Cisco ASR 901 Series Routers, you should configure the OSPFv3 authentication of the VLAN interface, instead of the physical interface. See the below example:

Device(config)# interface VLAN 60

Step 4

Do one of the following:

- ospfv3 authentication {ipsec spi} {md5 | sha1}{ key-encryption-type key} | null

- ipv6 ospf authentication {null | ipsec spi spi authentication-algorithm [key-encryption-type] [key]}

Example:

Device(config-if)# ospfv3 authentication md5 0 27576134094768132473302031209727

Example:
Or

Device(config-if)# ipv6 ospf authentication ipsec spi 500 md5 1234567890abcdef1234567890abcdef

Specifies the authentication type for an interface.

Defining Authentication in an OSPFv3 Area

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 router ospf process-id

4.    area area-id authentication ipsec spi spi authentication-algorithm [key-encryption-type] key

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

area area-id authentication ipsec spi spi authentication-algorithm [key-encryption-type] key

Example:

Device(config-rtr)# area 1 authentication ipsec spi 678 md5 1234567890ABCDEF1234567890ABCDEF

Enables authentication in an OSPFv3 area.

Configuration Examples for IPv6 Routing: OSPFv3 Authentication Support with IPsec

- Example: Defining Authentication on an Interface

- Example: Defining Authentication in an OSPFv3 Area

Example: Defining Authentication on an Interface

The following example shows how to define authentication on Ethernet interface 0/0:

interface Ethernet0/0
ipv6 enable
ipv6 ospf 1 area 0
ipv6 ospf authentication ipsec spi 500 md5 1234567890ABCDEF1234567890ABCDEF
interface Ethernet0/0
ipv6 enable
ipv6 ospf authentication null
ipv6 ospf 1 area 0

The following example shows how to define authentication on a VLAN interface of the Cisco ASR 901 Series Router:

interface Vlan60
ipv6 ospf encryption ipsec spi 300 esp 3des 4D92199549E0F2EF009B4160F3580E5528A11A45017F3887 md5 79054025245FB1A26E4BC422AEF54501

Example: Defining Authentication in an OSPFv3 Area

The following example shows how to define authentication on OSPFv3 area 0:

ipv6 router ospf 1
router-id 10.11.11.1
area 0 authentication ipsec spi 1000 md5 1234567890ABCDEF1234567890ABCDEF

Additional References for IPv6 Routing: OSPFv3 Authentication Support with IPsec

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

IPv6 Routing: OSPF for IPv6 Authentication Support with IPsec

“Configuring OSPF ” module in IP Routing: OSPF Configuration Guide

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for IPv6 Routing: OSPFv3 Authentication Support with IPsec

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for IPv6 Routing: OSPF for IPv6 Authentication Support with IPsec

Feature Name

Releases

Feature Information

IPv6 Routing: OSPF for IPv6 Authentication Support with IPsec

12.3(4)T

12.4

OSPFv3 uses the IPsec secure socket API to add authentication to OSPFv3 packets.

The following commands were introduced or modified: area authentication (IPv6), ipv6 ospf authentication, ipv6 router ospf, ospfv3 authentication.

Chapter 4. OSPFv2 Cryptographic Authentication

To prevent unauthorized or invalid routing updates in your network, Open Shortest Path First version 2 (OSPFv2) protocol packets must be authenticated.

There are two methods of authentication that are defined for OSPFv2: plain text authentication and cryptographic authentication. This module describes how to configure cryptographic authentication using the Hashed Message Authentication Code - Secure Hash Algorithm (HMAC-SHA). OSPFv2 specification (RFC 2328) allows only the Message-Digest 5 (MD5) algorithm for cryptographic authentication. However, RFC 5709 (OSPFv2 HMAC-SHA Cryptographic Authentication) allows OSPFv2 to use HMAC-SHA algorithms for cryptographic authentication.

- Finding Feature Information

- Prerequisites for OSPFv2 Cryptographic Authentication

- Information About OSPFv2 Cryptographic Authentication

- How to Configure OSPFv2 Cryptographic Authentication

- Configuration Examples for OSPFv2 Cryptographic Authentication

- Additional References for OSPFv2 Cryptographic Authentication

- Feature Information for OSPFv2 Cryptographic Authentication

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv2 Cryptographic Authentication

Ensure that Open Shortest Path First version 2 (OSPFv2) is configured on your network.

Information About OSPFv2 Cryptographic Authentication

- Configuring OSPFv2 Cryptographic Authentication

Configuring OSPFv2 Cryptographic Authentication

The OSPFv2 Cryptographic Authentication feature allows you to configure a key chain on the OSPF interface to authenticate OSPFv2 packets by using HMAC-SHA algorithms. You can use an existing key chain that is being used by another protocol, or you can create a key chain specifically for OSPFv2.

A key chain is a list of keys. Each key consists of a key string, which is also called the password or passcode. A key-string is essential for a key to be operational. Each key is identified by a unique key ID. To authenticate the OSPFv2 packets, it is essential that the cryptographic authentication algorithm be configured with a key. OSPFv2 supports keys with key IDs ranging from 1 to 255. The combination of the cryptographic authentication algorithm and the key is known as a Security Association (SA).

The authentication key on a key chain is valid for a specific time period called lifetime. An SA has the following configurable lifetimes:

- Accept lifetime

- Send lifetime

While adding a new key, the Send lifetime is set to a time in the future so that the same key can be configured on all devices in the network before the new key becomes operational. Old keys are removed only after the new key is operational on all devices in the network. When packets are received, the key ID is used to fetch the data for that key. The packet is verified using the cryptographic authentication algorithm and the configured key ID. If the key ID is not found, the packet is dropped.

Use the ip ospf authentication key-chain command to configure key chains for OSPFv2 cryptographic authentication.

Note

If OSPFv2 is configured to use a key chain, all MD5 keys that were previously configured using the ip ospf message-digest-key command are ignored.

How to Configure OSPFv2 Cryptographic Authentication

- Defining a Key Chain

- Defining Authentication on an Interface

Defining a Key Chain

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    key chain name

4.    key key-id

5.    key-string name

6.    cryptographic-algorithm name

7.    send-lifetime start-time {infinite | end-time | duration seconds}

8.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

key chain name

Example:

Device(config)# key chain sample1

Specifies the key chain name and enters key-chain configuration mode.

Step 4

key key-id

Example:

Device(config-keychain)# key 1

Specifies the key identifier and enters key-chain key configuration mode. The range is from 1 to 255.

Step 5

key-string name

Example:

Device(config-keychain-key)# key-string string1

Specifies the key string.

Step 6

cryptographic-algorithm name

Example:

Device(config-keychain-key)# cryptographic-algorithm hmac-sha-256

Configures the key with the specified cryptographic algorithm.

Step 7

send-lifetime start-time {infinite | end-time | duration seconds}

Example:

Device(config-keychain-key)# send-lifetime local 10:00:00 5 July 2013 infinite

Sets the time period during which an authentication key on a key chain is valid to be sent during key exchange with another device.

Step 8

end

Example:

Device(config-keychain-key)# end

Exits key-chain key configuration mode and returns to privileged EXEC mode.

Defining Authentication on an Interface

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ip ospf authentication key-chain name

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface gigabitethernet0/0/0

Specifies an interface type and number and enters interface configuration mode.

Step 4

ip ospf authentication key-chain name

Example:

Device(config-if)# ip ospf authentication key-chain ospf1

Specifies the key chain for an interface.

Step 5

end

Example:

Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Configuration Examples for OSPFv2 Cryptographic Authentication

- Example: Defining a Key Chain

- Example: Verifying a Key Chain

- Example: Defining Authentication on an Interface

- Example: Verifying Authentication on an Interface

Example: Defining a Key Chain

The following example shows how to configure a key chain:

Device> enable
Device# configure terminal
Device(config)# key chain sample1
Device(config-keychain)# key 1
Device(config-keychain-key)# key-string ThisIsASampleKey12345
Device(config-keychain-key)# cryptographic-algorithm hmac-sha-256
Device(config-keychain-key)# send-lifetime local 10:00:00 5 July 2013 infinite
Device(config-keychain-key)# end

Example: Verifying a Key Chain

The following sample output from the show key chain command displays the key chain information:

Device# show key chain Key-chain sample1

key 1 -- text "ThisIsASampleKey12345"
accept lifetime (always valid) - (always valid) [valid now]
send lifetime (10:00:00 PDT Jul 5 2013) - (infinite)

The table below describes the significant fields in the output:

show ip ospf interface Field Descriptions

Field

Description

key

Status of the configured key.

accept lifetime

The time interval within which the device accepts the key during key exchange with another device.

send lifetime

The time interval within which the device sends the key during a key exchange with another device.

Example: Defining Authentication on an Interface

The following example shows how to define authentication on Gigabit Ethernet interface 0/0/0:

Device> enable
Device# configure terminal
Device(config)# interface GigabitEthernet0/0/0
Device (config-if)# ip ospf authentication key-chain sample1
Device (config-if)# end

Example: Verifying Authentication on an Interface

The following sample output of the show ip ospf interface command displays the cryptographic key information:

Device# show ip ospf interface GigabitEthernet0/0/0

GigabitEthernet0/0/0 is up, line protocol is up
Internet Address 192.168.8.2/24, Area 1, Attached via Interface Enable
Process ID 1, Router ID 10.1.1.8, Network Type BROADCAST, Cost: 10
Topology-MTID    Cost    Disabled    Shutdown      Topology Name
0           10        no          no            Base
Enabled by interface config, including secondary ip addresses
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 10.1.1.8, Interface address 192.168.8.2
Backup Designated router (ID) 10.1.1.9, Interface address 192.168.8.9
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:00
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Can be protected by per-prefix Loop-Free FastReroute
Can be used for per-prefix Loop-Free FastReroute repair paths
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.1.1.9  (Backup Designated Router)
Suppress hello for 0 neighbor(s)
Cryptographic authentication enabled
Sending SA: Key 25, Algorithm HMAC-SHA-256 – key chain sample1

The table below describes the significant fields in the output:

show ip ospf interface Field Descriptions

Field

Description

GigabitEthernet

Status of the physical link and operational status of the protocol.

Internet Address

Interface IP address, subnet mask, and area address.

Area

OSPF area.

Process ID

OSPF process ID.

Cost

Administrative cost assigned to the interface.

Topology-MTID

MTR topology Multitopology Identifier (MTID) is a number assigned so that the protocol can identify the topology associated with information that it sends to its peers.

Transmit Delay

Transmit delay (in seconds), interface state, and router priority.

State

Operational state of the interface.

Designated Router

Designated router ID and respective interface IP address.

Backup Designated router

Backup designated router ID and respective interface IP address.

Timer intervals configured

Configuration of timer intervals.

Neighbor Count

Count of network neighbors and list of adjacent neighbors.

Cryptographic authentication

Status of cryptographic authentication.

Sending SA

Status of the sending SA (Security Association). Key, cryptographic algorithm, and key chain used.

Additional References for OSPFv2 Cryptographic Authentication

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Standards and RFCs

Standard

Title

RFC 2328

OSPF Version 2, April 1998

RFC 5709

OSPFv2 HMAC-SHA Cryptographic Authentication, October 2009

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv2 Cryptographic Authentication

Feature Information for OSPFv2 Cryptographic Authentication

Feature Name

Releases

Feature Information

OSPFv2 Cryptographic Authentication

15.4(1)T

The OSPFv2 Cryptographic Authentication feature prevents unauthorized or invalid routing updates in your network by authenticating Open Shortest Path First version 2 (OSPFv2) protocol packets using HMAC-SHA algorithms.

The following command was modified: ip ospf authentication.

Chapter 5. OSPFv3 IPSec ESP Encryption and Authentication

When Open Shortest Path First version 3 (OSPFv3) runs on IPv6, OSPFv3 requires the IPv6 encapsulating security payload (ESP) header or IPv6 authentication header to ensure integrity, authentication, and confidentiality of routing exchanges. IPv6 ESP extension headers can be used to provide authentication and confidentiality to OSPFv3.

- Finding Feature Information

- Prerequisites for OSPFv3 IPSec ESP Encryption and Authentication

- Information About OSPFv3 IPSec ESP Encryption and Authentication

- How to Configure OSPFv3 IPSec ESP Encryption and Authentication

- Configuration Examples for OSPFv3 IPSec ESP Encryption and Authentication

- Additional References

- Feature Information for OSPFv3 IPSec ESP Encryption and Authentication

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv3 IPSec ESP Encryption and Authentication

Configure the IP Security (IPsec) secure socket application program interface (API) on OSPFv3 in order to enable authentication and encryption.

Information About OSPFv3 IPSec ESP Encryption and Authentication

- OSPFv3 Authentication Support with IPsec

OSPFv3 Authentication Support with IPsec

In order to ensure that OSPFv3 packets are not altered and re-sent to the device, causing the device to behave in a way not desired by its system administrators, OSPFv3 packets must be authenticated. OSPFv3 uses the IPsec secure socket API to add authentication to OSPFv3 packets. This API supports IPv6.

OSPFv3 requires the use of IPsec to enable authentication. Crypto images are required to use authentication, because only crypto images include the IPsec API needed for use with OSPFv3.

In OSPFv3, authentication fields have been removed from OSPFv3 packet headers. When OSPFv3 runs on IPv6, OSPFv3 requires the IPv6 authentication header (AH) or IPv6 ESP header to ensure integrity, authentication, and confidentiality of routing exchanges. IPv6 AH and ESP extension headers can be used to provide authentication and confidentiality to OSPFv3.

To use the IPsec AH, you must enable the ipv6 ospf authentication command. To use the IPsec ESP header, you must enable the ipv6 ospf encryption command. The ESP header may be applied alone or in combination with the AH, and when ESP is used, both encryption and authentication are provided. Security services can be provided between a pair of communicating hosts, between a pair of communicating security gateways, or between a security gateway and a host.

To configure IPsec, you configure a security policy, which is a combination of the security policy index (SPI) and the key (the key is used to create and validate the hash value). IPsec for OSPFv3 can be configured on an interface or on an OSPFv3 area. For higher security, you should configure a different policy on each interface configured with IPsec. If you configure IPsec for an OSPFv3 area, the policy is applied to all of the interfaces in that area, except for the interfaces that have IPsec configured directly. Once IPsec is configured for OSPFv3, IPsec is invisible to you.

The secure socket API is used by applications to secure traffic. The API needs to allow the application to open, listen, and close secure sockets. The binding between the application and the secure socket layer also allows the secure socket layer to inform the application of changes to the socket, such as connection open and close events. The secure socket API is able to identify the socket; that is, it can identify the local and remote addresses, masks, ports, and protocol that carry the traffic requiring security.

Each interface has a secure socket state, which can be one of the following:

- NULL: Do not create a secure socket for the interface if authentication is configured for the area.

- DOWN: IPsec has been configured for the interface (or the area that contains the interface), but OSPFv3 either has not requested IPsec to create a secure socket for this interface, or there is an error condition.

- GOING UP: OSPFv3 has requested a secure socket from IPsec and is waiting for a CRYPTO_SS_SOCKET_UP message from IPsec.

- UP: OSPFv3 has received a CRYPTO_SS_SOCKET_UP message from IPsec.

- CLOSING: The secure socket for the interface has been closed. A new socket may be opened for the interface, in which case the current secure socket makes the transition to the DOWN state. Otherwise, the interface will become UNCONFIGURED.

- UNCONFIGURED: Authentication is not configured on the interface.

OSPFv3 will not send or accept packets while in the DOWN state.

- OSPFv3 Virtual Links

OSPFv3 Virtual Links

For each virtual link, a master security information datablock is created for the virtual link. Because a secure socket must be opened on each interface, there will be a corresponding security information datablock for each interface in the transit area. The secure socket state is kept in the interface’s security information datablock. The state field in the master security information datablock shows the status of all of the secure sockets opened for the virtual link. If all of the secure sockets are UP, then the security state for the virtual link will be set to UP.

Packets sent on a virtual link with IPsec must use predetermined source and destination addresses. The first local area address found in the device’s intra-area-prefix LSA for the area is used as the source address. This source address is saved in the area data structure and used when secure sockets are opened and packets sent over the virtual link. The virtual link will not transition to the point-to-point state until a source address is selected. Also, when the source or destination address changes, the previous secure sockets must be closed and new secure sockets opened.

Note

Virtual links are not supported for the IPv4 AF.

How to Configure OSPFv3 IPSec ESP Encryption and Authentication

- Defining Encryption on an Interface

- Defining Encryption in an OSPFv3 Area

- Defining Authentication and Encryption for a Virtual Link in an OSPFv3 Area

Defining Encryption on an Interface

Before You Begin

Before you configure IPsec on an interface, you must configure OSPFv3 on that interface.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    Do one of the following:

- ospfv3 encryption {ipsec spi spi esp encryption-algorithm key-encryption-type key authentication-algorithm key-encryption-type key | null}

- ipv6 ospf encryption {ipsec spi spi esp {encryption-algorithm [[key-encryption-type] key] | null} authentication-algorithm [key-encryption-type] key | null}

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface ethernet 0/0

Specifies an interface type and number, and places the device in interface configuration mode.

Step 4

Do one of the following:

- ospfv3 encryption {ipsec spi spi esp encryption-algorithm key-encryption-type key authentication-algorithm key-encryption-type key | null}

- ipv6 ospf encryption {ipsec spi spi esp {encryption-algorithm [[key-encryption-type] key] | null} authentication-algorithm [key-encryption-type] key | null}

Example:

Device(config-if)# ospfv3 encryption ipsec spi 1001 esp null md5 0 27576134094768132473302031209727

Example:

Device(config-if) ipv6 ospf encryption ipsec spi 1001 esp null sha1 123456789A123456789B123456789C123456789D

Specifies the encryption type for an interface.

Defining Encryption in an OSPFv3 Area

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 router ospf process-id

4.    area area-id encryption ipsec spi spi esp { encryption-algorithm [ | key-encryption-type] key | null} authentication-algorithm [ | key-encryption-type] key

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

area area-id encryption ipsec spi spi esp { encryption-algorithm [ | key-encryption-type] key | null} authentication-algorithm [ | key-encryption-type] key

Example:

Device(config-rtr)# area 1 encryption ipsec spi 500 esp null md5 1aaa2bbb3ccc4ddd5eee6fff7aaa8bbb

Enables encryption in an OSPFv3 area.

Defining Authentication and Encryption for a Virtual Link in an OSPFv3 Area

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 router ospf process-id

4.    area area-id virtual-link router-id authentication ipsec spi spi authentication-algorithm [ key-encryption-type] key

5.    area area-id virtual-link router-id encryption ipsec spi spi esp {encryption-algorithm [key-encryption-type] key | null} authentication-algorithm [key-encryption-type] key

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

area area-id virtual-link router-id authentication ipsec spi spi authentication-algorithm [ key-encryption-type] key

Example:

Device(config-rtr)# area 1 virtual-link 10.0.0.1 authentication ipsec spi 940 md5 1234567890ABCDEF1234567890ABCDEF

Enables authentication for virtual links in an OSPFv3 area.

Step 5

area area-id virtual-link router-id encryption ipsec spi spi esp {encryption-algorithm [key-encryption-type] key | null} authentication-algorithm [key-encryption-type] key

Example:

Device(config-rtr)# area 1 virtual-link 10.1.0.1 hello-interval 2 dead-interval 10 encryption ipsec spi 3944 esp null sha1 123456789A123456789B123456789C123456789D

Enables encryption for virtual links in an OSPFv3 area.

Configuration Examples for OSPFv3 IPSec ESP Encryption and Authentication

- Example: Defining Encryption in an OSPFv3 Area

Example: Defining Encryption in an OSPFv3 Area

Device# show ipv6 ospf interface

Ethernet0/0 is up, line protocol is up
Link Local Address 2001:0DB1:A8BB:CCFF:FE00:6E00, Interface ID 2
Area 0, Process ID 1, Instance ID 0, Router ID 10.10.10.1
Network Type BROADCAST, Cost:10
MD5 Authentication (Area) SPI 1000, secure socket state UP (errors:0)
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 10.11.11.1, local address 2001:0DB1:A8BB:CCFF:FE00:6F00
Backup Designated router (ID) 10.10.10.1, local address
FE80::A8BB:CCFF:FE00:6E00
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:03
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.11.11.1  (Designated Router)
Suppress hello for 0 neighbor(s)

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Command List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

Configuring BGP Nonstop Forwarding Awareness Using BGP Graceful Restart

“Configuring Advanced BGP Features” in the IP Routing: BGP Configuration Guide

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

—

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 IPSec ESP Encryption and Authentication

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 IPSec ESP Encryption and Authentication

Feature Name

Releases

Feature Information

OSPFv3 IPSec ESP Encryption and Authentication

12.4(9)T

15.1(1)SY

IPv6 ESP extension headers can be used to provide authentication and confidentiality to OSPFv3.

The following commands were introduced or modified: area encryption, area virtual-link, area virtual-link authentication, ipv6 ospf area, ipv6 ospf encryption, show ipv6 ospf interface, show ospfv3 interface.

Chapter 6. OSPF ABR Type 3 LSA Filtering

The OSPF ABR Type 3 LSA Filtering feature extends the ability of an ABR that is running the OSPF protocol to filter type 3 link-state advertisements (LSAs) that are sent between different OSPF areas. This feature allows only packets with specified prefixes to be sent from one area to another area and restricts all packets with other prefixes. This type of area filtering can be applied out of a specific OSPF area, into a specific OSPF area, or into and out of the same OSPF areas at the same time.

- Finding Feature Information

- Benefits

- Restrictions

- Configuration Tasks

- Configuration Examples

- Additional References

- Feature Information for the OSPF ABR Type 3 LSA Filtering

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Benefits

The OSPF ABR Type 3 LSA Filtering feature gives the administrator improved control of route distribution between OSPF areas.

Restrictions

Only type 3 LSAs that originate from an ABR are filtered.

- Related Features and Technologies

Related Features and Technologies

This feature is an extension of the OSPF routing protocol. For more information about configuring OSPF and configuring route summarization and filtering, refer to the "OSPF" module of the Cisco IOS IP Configuration Guide, Release 12.4 and the Cisco IOS IP Routing Protocols Command Reference, Release 12.4T.

Configuration Tasks

See the following sections for configuration tasks for the OSPF ABR Type 3 LSA Filtering feature. Each task in the list is identified as either required or optional:

- Configuring OSPF ABR Type 3 LSA Filtering

- Configuring OSPF ABR Type 3 LSA Filtering

- Verifying OSPF ABR Type 3 LSA Filtering

- Monitoring and Maintaining OSPF ABR Type 3 LSA Filtering

Configuring OSPF ABR Type 3 LSA Filtering

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# area area-id filter-list prefix prefix-list-name in

3.    Router(config-router)# exit

4.    Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value]

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Configures the router to run an OSPF process.

Step 2

Router(config-router)# area area-id filter-list prefix prefix-list-name in

Configures the router to filter interarea routes into the specified area.

Step 3

Router(config-router)# exit

Exits router configuration mode and returns to global configuration mode.

Step 4

Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value]

Creates a prefix list with the name specified for the list-name argument.

Configuring OSPF ABR Type 3 LSA Filtering

To filter interarea routes out of a specified area, use the following commands beginning in router configuration mode:

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# area area-id filter-list prefix prefix-list-name out

3.    Router(config-router)# exit

4.    Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value]

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Configures the router to run an OSPF process.

Step 2

Router(config-router)# area area-id filter-list prefix prefix-list-name out

Configures the router to filter interarea routes out of the specified area.

Step 3

Router(config-router)# exit

Exits router configuration mode and returns to global configuration mode.

Step 4

Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value]

Creates a prefix list with the name specified for the list-name argument.

Verifying OSPF ABR Type 3 LSA Filtering

To verify that the OSPF ABR Type 3 LSA Filtering feature has been configured, use the show ip ospf command in the EXEC mode. The show ip ospf command will show that this feature has been enabled by listing the area filter as "in" or "out." The following is sample output from the show ip ospf command:

router# show ip ospf 1
Routing Process "ospf 1" with ID 172.16.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
It is an area border router
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x0
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 2. 2 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 2
Area has no authentication
SPF algorithm executed 6 times
Area ranges are
10.0.0.0/8 Passive Advertise
Area-filter AREA_0_IN in
Area-filter AREA_0_OUT out
Number of LSA 5. Checksum Sum 0x29450
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
Area 1
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm executed 4 times
Area ranges are
Area-filter AREA_1_IN in
Area-filter AREA_1_OUT out
Number of LSA 6. Checksum Sum 0x30100
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0

Monitoring and Maintaining OSPF ABR Type 3 LSA Filtering

Command

Purpose

Router# show ip prefix-list

Displays information about a prefix list or prefix list entries.

Configuration Examples

The following configuration example output shows interarea filtering that is applied to both incoming and outgoing routes:

Router(config)# router ospf 1
log-adjacency-changes
area 1 filter-list prefix AREA_1_OUT out
area 3 filter-list prefix AREA_3_IN in
network 10.0.0.0 0.255.255.255 area 3
network 172.16.1.0 0.0.0.255 area 0
network 192.168.0.0 0.255.255.255 area 1
!
ip prefix-list AREA_1_OUT seq 10 permit 10.25.0.0/8 ge 16
ip prefix-list AREA_1_OUT seq 20 permit 172.20.20.0/24
!
ip prefix-list AREA_3_IN seq 10 permit 172.31.0.0/16
!

Additional References

The following sections provide references related to OSPF ABR Type 3 LSA Filtering.

Related Documents

Related Topic

Document Title

Configuring OSPF ABR Type 3 LSA Filtering

Configuring OSPF ABR Type 3 LSA Filtering

OSPF commands: complete command syntax, command mode, command history, command defaults, usage guidelines, and examples

Cisco IOS IP Routing: OSPF Command Reference

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

None

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for the OSPF ABR Type 3 LSA Filtering

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF ABR Type 3 LSA Filtering

Feature Name

Releases

Feature Informatoin

OSPF ABR Type 3 LSA Filtering

12.2(4)T

This feature was integrated into Cisco IOS Release 12.2(4)T.

OSPF ABR Type 3 LSA Filtering

12.2(4)T3

Support for the Cisco 7500 series was added in Cisco IOS Release 12.2(4)T3.

OSPF ABR Type 3 LSA Filtering

12.2(8)T

Support for the Cisco 1710, 1721, 3631, 3725, 3745 and IGX 8400 series URM was added in Cisco IOS Release 12.2(8)T.

OSPF ABR Type 3 LSA Filtering

12.2(11)T

Support for the Cisco AS5300, AS5400, and AS5800 series was integrated into Cisco IOS Release 12.2(11)T.

Chapter 7. OSPF Stub Router Advertisement

The OSPF Stub Router Advertisement feature allows you to bring a new router into a network without immediately routing traffic through the new router and allows you to gracefully shut down or reload a router without dropping packets that are destined for other networks.

- Finding Feature Information

- Information About OSPF Stub Router Advertisement

- Supported Platforms

- How to Configure OSPF Stub Router Advertisement

- Configuration Examples of OSPF Stub Router Advertisement

- Additional References

- Feature Information for OSPF Stub Router Advertisement

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPF Stub Router Advertisement

- OSPF Stub Router Advertisement Functionality

- Allowing Routing Tables to Converge

- Configuring a Graceful Shutdown

- Benefits of OSPF Stub Router Advertisement

- Related Features and Technologies

OSPF Stub Router Advertisement Functionality

The OSPF Stub Router Advertisement feature allows you to bring a new router into a network without immediately routing traffic through the new router and allows you to gracefully shut down or reload a router without dropping packets that are destined for other networks. This feature introduces three configuration options that allow you to configure a router that is running the Open Shortest Path First (OSPF) protocol to advertise a maximum or infinite metric to all neighbors.

When any of these three configuration options are enabled on a router, the router will originate link-state advertisements (LSAs) with a maximum metric (LSInfinity: 0xFFFF) through all nonstub links. The advertisement of a maximum metric causes other routers to assign a cost to the new router that is higher than the cost of using an alternate path. Because of the high cost assigned to paths that pass through the new router, other routers will not use a path through the new router as a transit path to forward traffic that is destined for other networks, which allows switching and routing functions to be up and running and routing tables to converge before transit traffic is routed through this router.

Note

Directly connected links in a stub network are not affected by the configuration of a maximum or infinite metric because the cost of a stub link is always set to the output interface cost.

Allowing Routing Tables to Converge

Two configuration options introduced by the OSPF Stub Router Advertisement feature allow you to bring a new router into a network without immediately routing traffic through the new router. These configuration options are useful because Interior Gateway Protocols (IGPs) converge very quickly upon a router during startup or after a reload, often before Border Gateway Protocol (BGP) routing tables have completely converged. If neighbor routers forward traffic through a router while that router is building BGP routing tables, packets that have been received for other destinations may be dropped. Advertising a maximum metric during startup will allow routing tables to converge before traffic that is destined for other networks is sent through the router. The following two configuration options enable a router to advertise a maximum metric at startup:

- You can configure a timer to advertise a maximum metric when the router is started or reloaded. When this option is configured, the router will advertise a maximum metric, which forces neighbor routers to select alternate paths until the timer expires. When the timer expires, the router will advertise accurate (normal) metrics, and other routers will send traffic to this router depending on the cost. The configurable range of the timer is from 5 to 86,400 seconds.

- You can configure a router to advertise a maximum metric at startup until BGP routing tables converge or until the default timer expires (600 seconds). Once BGP routing tables converge or the default timer expires, the router will advertise accurate (normal) metrics and other routers will send traffic to this router, depending on the cost.

Configuring a Graceful Shutdown

The third configuration option introduced by the OSPF Stub Router Advertisement feature allows you to gracefully remove a router from the network by advertising a maximum metric through all links, which allows other routers to select alternate paths for transit traffic to follow before the router is shut down. There are many situations where you may need to remove a router from the network. If a router is removed from a network and neighbor routers cannot detect that the physical interface is down, neighbors will need to wait for dead timers to expire before the neighbors will remove the adjacency and routing tables will reconverge. This situation may occur when there is a switch between other routers and the router that is shut down. Packets may be dropped while the neighbor routing tables reconverge.

When this third option is configured, the router advertises a maximum metric, which allows neighbor routers to select alternate paths before the router is shut down. This configuration option could also be used to remove a router that is in a critical condition from the network without affecting traffic that is destined for other networks.

Note

You should not save the running configuration of a router when it is configured for a graceful shutdown because the router will continue to advertise a maximum metric after it is reloaded.

Benefits of OSPF Stub Router Advertisement

Improved Stability and Availability

Advertising a maximum metric through all links at startup or during a reload will prevent neighbor routers from using a path through the router as a transit path, thereby reducing the number of packets that are dropped and improving the stability and availability of the network.

Graceful Removal from the Network

Advertising a maximum metric before shutdown allows other routers to select alternate paths before the transit path through a router becomes inaccessible.

Related Features and Technologies

The OSPF Stub Router Advertisement feature is an extension of the OSPF routing protocol. For more information about configuring OSPF and BGP, refer to the Cisco IOS IP Routing Configuration Guide and the Cisco IOS IP Routing Command Reference .

Supported Platforms

The OSPF Stub Router Advertisement feature is supported by the following platforms in Cisco IOS Release 12.2(14)S that support OSPF:

- Cisco 7200 series

- Cisco 7400 series

- Cisco 7500 series

Determining Platform Support Through Cisco Feature Navigator

Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Cisco Feature Navigator is a web-based tool that enables you to determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.

Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:

Click Here

Availability of Cisco IOS Software Images

Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without prior notice. For updated information about platform support and availability of software images for each Cisco IOS software release, refer to the online release notes or, if supported, Cisco Feature Navigator.

How to Configure OSPF Stub Router Advertisement

See the following sections for configuration tasks to configure OSPF to advertise a maximum metric. This feature has three different configuration options. All tasks are optional and should be individually configured.

- Configuring Advertisement on Startup

- Configuring Advertisement Until Routing Tables Converge

- Configuring Advertisement for a Graceful Shutdown

- Verifying the Advertisement of a Maximum Metric

- Monitoring and Maintaining OSPF Stub Router Advertisement

Configuring Advertisement on Startup

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# max-metric router-lsa on-startup announce-time

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Places the router in router configuration mode and enables an OSPF routing process.

Step 2

Router(config-router)# max-metric router-lsa on-startup announce-time

Configures OSPF to advertise a maximum metric during startup for a configured period of time. The announce-time argument is a configurable timer that must follow the on-startup keyword to be configured. There is no default timer value. The configurable time range is from 5 to 86,400 seconds.

Configuring Advertisement Until Routing Tables Converge

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# max-metric router-lsa on-startup wait-for-bgp

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Places the router in router configuration mode and enables an OSPF routing process.

Step 2

Router(config-router)# max-metric router-lsa on-startup wait-for-bgp

Configures OSPF to advertise a maximum metric until BGP routing tables have converged or until the default timer has expired. The wait-for-bgp keyword must follow the on-startup keyword to be configured. The default timer value is 600 seconds.

Configuring Advertisement for a Graceful Shutdown

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# max-metric router-lsa

3.    Router(config-router)# exit

4.    Router(config)# exit

5.    Router# show ip ospf

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Places the router in router configuration mode and enables an OSPF routing process.

Step 2

Router(config-router)# max-metric router-lsa

Configures OSPF to advertise a maximum metric until the router is shut down.

Step 3

Router(config-router)# exit

Exits router configuration mode.

Step 4

Router(config)# exit

Exits configuration mode and places the router in privileged EXEC mode.

Step 5

Router# show ip ospf

Displays general information about OSPF routing processes. The show ip ospf command is entered in order to verify that the max-metric router-lsa command has been enabled before the router is shut down or reloaded.

What to Do Next

Note

You should not save the running configuration of a router when it is configured for a graceful shutdown because the router will continue to advertise a maximum metric after it is reloaded.

Verifying the Advertisement of a Maximum Metric

To verify that the advertisement of a maximum metric has been configured correctly, use the show ip ospfor show ip ospf databasecommand.

The output of the show ip ospfcommand will display the condition, state, and remaining time delay of the advertisement of a maximum metric, depending on which options were configured with the max-metric router-lsa command.

The following sample output is similar to the output that will be displayed when the on-startupkeyword and announce-time argument are configured with the max-metric router-lsa command:

Router# show ip ospf
Routing Process "ospf 1998" with ID 10.18.134.155
Supports only single TOS(TOS0) routes
Supports opaque LSA
It is an area border and autonomous system boundary router
Redistributing External Routes from,
static, includes subnets in redistribution
Originating router-LSAs with maximum metric, Time remaining: 00:01:18
Condition: on startup for 300 seconds, State: active
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 7. Checksum Sum 0x47261
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 2. 1 normal 0 stub 1 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm executed 3 times
Area ranges are
Number of LSA 8. Checksum Sum 0x474AE
Number of opaque link LSA 0. Checksum Sum 0x0

The following sample output is similar to the output that will be displayed when the on-startupand wait-for-bgp keywords are configured with the max-metric router-lsa command:

Router# show ip ospf
Routing Process "ospf 1998" with ID 10.18.134.155
Supports only single TOS(TOS0) routes
Supports opaque LSA
It is an area border and autonomous system boundary router
Redistributing External Routes from,
static, includes subnets in redistribution
Originating router-LSAs with maximum metric, Time remaining: 00:01:18
Condition: on startup while BGP is converging, State: active
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 7. Checksum Sum 0x47261
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 2. 1 normal 0 stub 1 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm executed 3 times
Area ranges are
Number of LSA 8. Checksum Sum 0x474AE
Number of opaque link LSA 0. Checksum Sum 0x0

The following sample output is similar to the output that will be displayed when the max-metric router-lsa command is configured without any keywords or arguments:

Router# show ip ospf
Routing Process "ospf 1998" with ID 10.18.134.155
Supports only single TOS(TOS0) routes
Supports opaque LSA
It is an area border and autonomous system boundary router
Redistributing External Routes from,
static, includes subnets in redistribution
Originating router-LSAs with maximum metric
Condition: always, State: active
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 7. Checksum Sum 0x47261
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 2. 1 normal 0 stub 1 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm executed 3 times
Area ranges are
Number of LSA 8. Checksum Sum 0x474AE
Number of opaque link LSA 0. Checksum Sum 0x0

The output of the show ip ospf databasecommand will display information about OSPF LSAs and indicate if the router is announcing maximum cost links. The following sample output is similar to the output that will be displayed when any form of the max-metric router-lsa command is configured:

Router# show ip ospf database
Exception Flag: Announcing maximum link costs
LS age: 68
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 172.18.134.155
Advertising Router: 172.18.134.155
LS Seq Number: 80000002
Checksum: 0x175D
Length: 60
Area Border Router
AS Boundary Router
Number of Links: 3

Link connected to: a Transit Network
(Link ID) Designated Router address: 192.168.1.11
(Link Data) Router Interface address: 192.168.1.14
Number of TOS metrics: 0
TOS 0 Metrics: 65535 (metric used for local calculation: 10)

Link connected to: a Transit Network
(Link ID) Designated Router address: 10.1.145.11
(Link Data) Router Interface address: 10.1.145.14
Number of TOS metrics: 0
TOS 0 Metrics: 65535 (metric used for local calculation: 10)

Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.11.12.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 1

Monitoring and Maintaining OSPF Stub Router Advertisement

Command

Purpose

Router# show ip ospf

Displays general information about OSPF routing processes and provides information about the configuration settings and status of the OSPF Stub Router Advertisement feature.

Router# show ip ospf database router

Displays information about router LSAs, and indicates if a router is announcing maximum link costs.

Configuration Examples of OSPF Stub Router Advertisement

- Example Advertisement on Startup

- Example Advertisement Until Routing Tables Converge

- Example Graceful Shutdown

Example Advertisement on Startup

In the following example, a router that is running OSPF is configured to advertise a maximum metric at startup for 300 seconds:

Router(config)# router ospf 100
Router(config-router)# max-metric router-lsa on-startup 300

Example Advertisement Until Routing Tables Converge

In the following example, a router that is running OSPF is configured to advertise a maximum metric until BGP routing tables converge or until the default timer expires (600 seconds):

Router(config)# router ospf 100
Router(config-router)# max-metric router-lsa on-startup wait-for-bgp

Example Graceful Shutdown

In the following example, a router that is running OSPF is configured to advertise a maximum metric until the router is shut down:

Router(config)# router ospf 100
Router(config-router)# max-metric router-lsa
Router(config-router)# exit
Router(config)# exit
Router# show ip ospf

Additional References

Related Documents

Related Topic

Document Title

Configuring OSPF

"Configuring OSPF"

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Cisco IOS master command list, all releases

Cisco IOS Master Command List, All Releases

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

RFC 3137

OSPF Stub Router Advertisement

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Stub Router Advertisement

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Stub Router Advertisement

Feature Name

Releases

Feature Information

OSPF Stub Router Advertisement

12.1(8)E 12.0(15)S 12.0(15)SC 12.0(16)ST 12.2(4)T 12.2(4)T3 12.2(14)S Cisco IOS XE 3.1.0 SG

The OSPF Stub Router Advertisement feature allows you to bring a new router into a network without immediately routing traffic through the new router and allows you to gracefully shut down or reload a router without dropping packets that are destined for other networks.

The following commands are introduced or modified in the feature documented in this module:

- max-metric router-lsa

- show ip ospf

Chapter 8. OSPF Update Packet-Pacing Configurable Timers

This module describes the OSPF Update Packet-Pacing Configurable Timers feature, which allows you to configure the rate at which OSPF LSA flood pacing, retransmission pacing, and group pacing updates occur.

- Finding Feature Information

- Restrictions on OSPF Update Packet-Pacing Configurable Timers

- Information About OSPF Update Packet-Pacing Configurable Timers

- Supported Platforms

- How to Configure OSPF Packet-Pacing Timers

- Configuration Examples of OSPF Update Packet-Pacing

- Additional References

- Feature Information for OSPF Update Packet-Pacing Configurable Timers

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Restrictions on OSPF Update Packet-Pacing Configurable Timers

Do not change the packet pacing timers unless all other options to meet OSPF packet flooding requirements have been exhausted. Specifically, network operators should prefer summarization, stub area usage, queue tuning, and buffer tuning before changing the default timers. Furthermore, there are no guidelines for changing timer values; each OSPF deployment is unique and should be considered on a case-by-case basis. The network operator assumes risks associated with changing the default timer values.

Information About OSPF Update Packet-Pacing Configurable Timers

- Functionality of the OSPF Update Packet-Pacing Timers

- Benefits of OSPF Update Packet-Pacing Configurable Timers

- Related Features and Technologies

Functionality of the OSPF Update Packet-Pacing Timers

In rare situations, you might need to change Open Shortest Path First (OSPF) packet-pacing default timers to mitigate CPU or buffer utilization issues associated with flooding very large numbers of link-state advertisements (LSAs). The OSPF Update Packet-Pacing Configurable Timers feature allows you to configure the rate at which OSPF LSA flood pacing, retransmission pacing, and group pacing updates occur.

Configuring OSPF flood pacing timers allows you to control interpacket spacing between consecutive link-state update packets in the OSPF transmission queue. Configuring OSPF retransmission pacing timers allows you to control interpacket spacing between consecutive link-state update packets in the OSPF retransmission queue. Cisco IOS software groups the periodic refresh of LSAs to improve the LSA packing density for the refreshes in large topologies. The group timer controls the interval used for group LSA refreshment; however, this timer does not change the frequency that individual LSAs are refreshed (the default refresh occurs every 30 minutes).

Note

The default settings for OSPF packet pacing timers are suitable for the majority of OSPF deployments. You should change the default timers only as a last resort.

Benefits of OSPF Update Packet-Pacing Configurable Timers

The OSPF Update Packet-Pacing Configurable Timers feature provides the administrator with a mechanism to control the rate at which LSA updates occur in order to reduce high CPU or buffer utilization that can occur when an area is flooded with a very large number of LSAs.

Related Features and Technologies

The OSPF Update Packet-Pacing Configurable Timers feature is an extension of the OSPF routing protocol. For more information about configuring OSPF, packet pacing, area border router (ABR) and autonomous system boundary router (ASBR) summarization, and stub router configuration, refer to the "Configuring OSPF" module of the Cisco IOS IP Routing Configuration Guide and the Cisco IOS IP Routing: OSPF Command Reference.

Supported Platforms

The OSPF Update Packet-Pacing Configurable Timers feature is supported by the following platforms in Cisco IOS Release 12.2(14)S that support OSPF:

- Cisco 7200 series

- Cisco 7400 series

- Cisco 7500 series

Determining Platform Support Through Cisco Feature Navigator

Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Cisco Feature Navigator is a web-based tool that enables you to determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.

Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:

Click Here

Availability of Cisco IOS Software Images

Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without prior notice. For updated information about platform support and availability of software images for each Cisco IOS software release, refer to the online release notes or, if supported, Cisco Feature Navigator.

How to Configure OSPF Packet-Pacing Timers

See the following sections for configuration tasks for the OSPF Update Packet-Pacing Configurable Timers feature. Each task in the list is identified as either required or optional:

- Configuring OSPF Packet-Pacing Timers

- Configuring a Group Packet Pacing Timer

- Configuring a Group Packet Pacing Timer

- Verifying OSPF Packet-Pacing Timers

- Monitoring and Maintaining OSPF Packet-Pacing Timers

Configuring OSPF Packet-Pacing Timers

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# timers pacing flood milliseconds

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Places the router in router configuration mode and enables an OSPF routing process.

Step 2

Router(config-router)# timers pacing flood milliseconds

Configures a flood packet pacing timer delay (in milliseconds).

Configuring a Group Packet Pacing Timer

To configure a retransmission packet pacing timer, use the following commands beginning in router configuration mode:

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# timers pacing lsa-group seconds

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Places the router in router configuration mode and enables an OSPF routing process.

Step 2

Router(config-router)# timers pacing lsa-group seconds

Configures an LSA group packet pacing timer delay (in seconds).

Configuring a Group Packet Pacing Timer

To configure a retransmission packet pacing timer, use the following commands beginning in router configuration mode:

SUMMARY STEPS

1.    Router(config)# router ospf process-id

2.    Router(config-router)# timers pacing lsa-group seconds

DETAILED STEPS

Command or Action

Purpose

Step 1

Router(config)# router ospf process-id

Places the router in router configuration mode and enables an OSPF routing process.

Step 2

Router(config-router)# timers pacing lsa-group seconds

Configures an LSA group packet pacing timer delay (in seconds).

Verifying OSPF Packet-Pacing Timers

To verify that OSPF packet pacing has been configured, use the show ip ospfprivileged EXEC command. The output of the show ip ospfcommand will display the type and delay time of the configurable pacing timers (flood, retransmission, group). The following example output is from the show ip ospfcommand:

Router# show ip ospf
Routing Process "ospf 1" with ID 10.0.0.1 and Domain ID 10.20.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
LSA group pacing timer 100 secs
Interface flood pacing timer 55 msecs
Retransmission pacing timer 100 msecs
Number of external LSA 0. Checksum Sum 0x0
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 2. 2 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 2
Area has message digest authentication
SPF algorithm executed 4 times
Area ranges are
Number of LSA 4. Checksum Sum 0x29BEB
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 3
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0
Area 172.16.26.0
Number of interfaces in this area is 0
Area has no authentication
SPF algorithm executed 1 times
Area ranges are
192.168.0.0/16 Passive Advertise
Number of LSA 1. Checksum Sum 0x44FD
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 1
Number of indication LSA 1
Number of DoNotAge LSA 0
Flood list length 0

- Troubleshooting Tips

Troubleshooting Tips

If the number of OSPF packet retransmissions rapidly increases, increase the value of the packet pacing timers. The number of OSPF packet retransmissions is displayed in the output of the show ip ospf neighbor command.

Monitoring and Maintaining OSPF Packet-Pacing Timers

Command

Purpose

Router# show ip ospf

Displays general information about OSPF routing processes.

router# show ip ospf neighbor

Displays OSPF neighbor information on a per-interface basis.

Router# clear ip ospf redistribution

Clears route redistribution based on the OSPF routing process ID.

Configuration Examples of OSPF Update Packet-Pacing

- Example Flood Pacing

- Example Retransmission Pacing

- Example Group Pacing

Example Flood Pacing

The following example configures LSA flood pacing updates to occur in 50-millisecond intervals for OSPF routing process 1:

Router(config)# router ospf 1
Router(config-router)# timers pacing flood 50

Example Retransmission Pacing

The following example configures retransmission pacing updates to occur in 100-millisecond intervals for OSPF routing process 1:

Router(config)# router ospf 1
Router(config-router)# timers pacing retransmission 100

Example Group Pacing

The following example configures OSPF group pacing updates between LSA groups to occur in 75-second intervals for OSPF routing process 1:

Router(config)# router ospf 1
Router(config-router)# timers pacing lsa-group 75

Additional References

Related Documents

Related Topic

Document Title

Configuring OSPF

Configuring OSPF"

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Cisco IOS master command list, all releases

Cisco IOS Master Command List, All Releases

Standards

Standard

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIB

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco IOS XE software releases , and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Update Packet-Pacing Configurable Timers

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Update Packet-Pacing Configurable Timers

Feature Name

Releases

Feature Information

OSPF Update Packet-Pacing Configurable Timers

12.2(4)T 12.2(4)T3 12.2(8)T 12.2(8)T1 12.2(14)S Cisco IOS XE 3.1.0 SG

The OSPF Update Packet-Pacing Configurable Timers feature allows you to configure the rate at which OSPF LSA flood pacing, retransmission pacing, and group pacing updates occur.

The following commands are introduced or modified in the feature documented in this module:

- timers pacing flood

- timers pacing lsa-group

- timers pacing retransmission

- show ip ospf

Chapter 9. OSPF Sham-Link Support for MPLS VPN

Feature History

Release

Modification

12.2(8)T

This feature was introduced.

This module describes how to configure and use a sham-link to connect Virtual Private Network (VPN) client sites that run the Open Shortest Path First (OSPF) protocol and share backdoor OSPF links in a Multiprotocol Label Switching (MPLS) VPN configuration.

- Finding Feature Information

- Feature Overview

- Supported Platforms

- Supported Standards MIBs and RFCs

- Prerequisites

- Configuration Tasks

- Monitoring and Maintaining a Sham-Link

- Configuration Examples

- Glossary

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Feature Overview

- Using OSPF in PE-CE Router Connections

- Using a Sham-Link to Correct OSPF Backdoor Routing

- Sham-Link Configuration Example

- Benefits

- Restrictions

- Related Features and Technologies

- Related Documents

Using OSPF in PE-CE Router Connections

In an MPLS VPN configuration, the OSPF protocol is one way you can connect customer edge (CE) routers to service provider edge (PE) routers in the VPN backbone. OSPF is often used by customers that run OSPF as their intrasite routing protocol, subscribe to a VPN service, and want to exchange routing information between their sites using OSPF (during migration or on a permanent basis) over an MPLS VPN backbone.

The figure below shows an example of how VPN client sites that run OSPF can connect over an MPLS VPN backbone.

When OSPF is used to connect PE and CE routers, all routing information learned from a VPN site is placed in the VPN routing and forwarding (VRF) instance associated with the incoming interface. The PE routers that attach to the VPN use the Border Gateway Protocol (BGP) to distribute VPN routes to each other. A CE router can then learn the routes to other sites in the VPN by peering with its attached PE router. The MPLS VPN superbackbone provides an additional level of routing hierarchy to interconnect the VPN sites running OSPF.

When OSPF routes are propagated over the MPLS VPN backbone, additional information about the prefix in the form of BGP extended communities (route type, domain ID extended communities) is appended to the BGP update. This community information is used by the receiving PE router to decide the type of link-state advertisement (LSA) to be generated when the BGP route is redistributed to the OSPF PE-CE process. In this way, internal OSPF routes that belong to the same VPN and are advertised over the VPN backbone are seen as interarea routes on the remote sites.

For basic information about how to configure an MPLS VPN, refer to the "MPLS Virtual Private Networks Configuration" module.

Using a Sham-Link to Correct OSPF Backdoor Routing

Although OSPF PE-CE connections assume that the only path between two client sites is across the MPLS VPN backbone, backdoor paths between VPN sites (shown in grey in the figure below) may exist. If these sites belong to the same OSPF area, the path over a backdoor link will always be selected because OSPF prefers intraarea paths to interarea paths. (PE routers advertise OSPF routes learned over the VPN backbone as interarea paths.) For this reason, OSPF backdoor links between VPN sites must be taken into account so that routing is performed based on policy.

For example, the figure above shows three client sites, each with backdoor links. Because each site runs OSPF within the same Area 1 configuration, all routing between the three sites follows the intraarea path across the backdoor links, rather than over the MPLS VPN backbone.

The following example shows BGP routing table entries for the prefix 10.3.1.7/32 in the PE-1 router in the figure above. This prefix is the loopback interface of the Winchester CE router. As shown in bold in this example, the loopback interface is learned via BGP from PE-2 and PE-3. It is also generated through redistribution into BGP on PE-1.

PE-1# show ip bgp vpnv4 all 10.3.1.7
BGP routing table entry for 100:251:10.3.1.7/32, version 58
Paths: (3 available, best #2)
Advertised to non peer-group peers:
10.3.1.2 10.3.1.5
Local
10.3.1.5 (metric 30) from 10.3.1.5 (10.3.1.5)
Origin incomplete, metric 22, localpref 100, valid, internal
Extended Community: RT:1:793 OSPF DOMAIN ID:0.0.0.100 OSPF
RT:1:2:0 OSPF 2
Local
10.2.1.38 from 0.0.0.0 (10.3.1.6)
Origin incomplete, metric 86, localpref 100, weight 32768,
valid, sourced, best
Extended Community: RT:1:793 OSPF DOMAIN ID:0.0.0.100 OSPF
RT:1:2:0 OSPF 2
Local
10.3.1.2 (metric 30) from 10.3.1.2 (10.3.1.2)
Origin incomplete, metric 11, localpref 100, valid, internal
Extended Community: RT:1:793 OSPF DOMAIN ID:0.0.0.100 OSPF
RT:1:2:0 OSPF 2

Within BGP, the locally generated route (10.2.1.38) is considered to be the best route. However, as shown in bold in the next example, the VRF routing table shows that the selected path is learned via OSPF with a next hop of 10.2.1.38, which is the Vienna CE router.

PE-1# show ip route vrf ospf 10.3.1.7
Routing entry for 10.3.1.7/32
Known via "ospf 100", distance 110, metric 86, type intra area
Redistributing via bgp 215
Advertised by bgp 215
Last update from 10.2.1.38 on Serial0/0/0, 00:00:17 ago
Routing Descriptor Blocks:
* 10.2.1.38
, from 10.3.1.7, 00:00:17 ago, via Serial0/0/0
Route metric is 86, traffic share count is 1

This path is selected because:

- The OSPF intra-area path is preferred over the interarea path (over the MPLS VPN backbone) generated by the PE-1 router.

- OSPF has a lower administrative distance (AD) than internal BGP (BGP running between routers in the same autonomous system).

If the backdoor links between sites are used only for backup purposes and do not participate in the VPN service, then the default route selection shown in the preceding example is not acceptable. To reestablish the desired path selection over the MPLS VPN backbone, you must create an additional OSPF intra-area (logical) link between ingress and egress VRFs on the relevant PE routers. This link is called a sham-link.

A sham-link is required between any two VPN sites that belong to the same OSPF area and share an OSPF backdoor link. If no backdoor link exists between the sites, no sham-link is required.

The figure below shows a sample sham-link between PE-1 and PE-2. A cost is configured with each sham-link and is used to decide whether traffic will be sent over the backdoor path or the sham-link path. When a sham-link is configured between PE routers, the PEs can populate the VRF routing table with the OSPF routes learned over the sham-link.

Because the sham-link is seen as an intra-area link between PE routers, an OSPF adjacency is created and database exchange (for the particular OSPF process) occurs across the link. The PE router can then flood LSAs between sites from across the MPLS VPN backbone. As a result, the desired intra-area connectivity is created.

The section, "Creating a Sham-Link", describes how to configure a sham-link between two PE routers. For more information about how to configure OSPF, refer to the "Configuring OSPF" module.

Sham-Link Configuration Example

The example in this section is designed to show how a sham-link is used only to affect the OSPF intra-area path selection of the PE and CE routers. The PE router also uses the information received from MP-BGP to set the outgoing label stack of incoming packets, and to decide to which egress PE router to label switch the packets.

The figure below shows a sample MPLS VPN topology in which a sham-link configuration is necessary. A VPN client has three sites, each with a backdoor link. Two sham-links have been configured, one between PE-1 and PE-2, and another between PE-2 and PE-3. A sham-link between PE-1 and PE-3 is not necessary in this configuration because the Vienna and Winchester sites do not share a backdoor link.

The following example shows the forwarding that occurs between sites from the standpoint of how PE-1 views the 10.3.1.7/32 prefix, the loopback1 interface of the Winchester CE router in the figure above.

PE-1# show ip bgp vpnv4 all 10.3.1.7
BGP routing table entry for 100:251:10.3.1.7/32, version 124
Paths: (1 available, best #1)
Local
10.3.1.2 (metric 30) from 10.3.1.2
(10.3.1.2)
Origin incomplete, metric 11, localpref 100, valid, internal,
best
Extended Community: RT:1:793 OSPF DOMAIN ID:0.0.0.100 OSPF
RT:1:2:0 OSPF 2
PE-1# show ip route vrf ospf 10.3.1.7
Routing entry for 10.3.1.7/32
Known via "ospf 100
", distance 110, metric 13, type intra area
Redistributing via bgp 215
Last update from 10.3.1.2 00:12:59 ago
Routing Descriptor Blocks:
10.3.1.2 (Default-IP-Routing-Table), from 10.3.1.7, 00:12:59 ago

The next example shows forwarding information in which the next hop for the route, 10.3.1.2, is the PE-3 router rather than the PE-2 router (which is the best path according to OSPF). The reason the OSPF route is not redistributed to BGP on the PE is because the other end of the sham-link already redistributed the route to BGP and there is no need for duplication. The OSPF sham-link is used only to influence intra-area path selection. When sending traffic to a particular destination, the PE router uses the MP-BGP forwarding information.

PE-1# show ip bgp vpnv4 all tag | begin 10.3.1.7
10.3.1.7/32      10.3.1.2
notag/38

PE-1# show tag-switching forwarding 10.3.1.2
Local  Outgoing   Prefix           Bytes tag  Outgoing   Next Hop
tag    tag or VC  or Tunnel Id     switched   interface
31    42         10.3.1.2/32
0          PO3/0/0    point2point
PE-1# show ip cef vrf ospf 10.3.1.7
10.3.1.7/32, version 73, epoch 0, cached adjacency to POS3/0/0
0 packets, 0 bytes
tag information set
local tag: VPN-route-head
fast tag rewrite with PO3/0/0, point2point, tags imposed: {42 38
}
via 10.3.1.2
, 0 dependencies, recursive
next hop 10.1.1.17, POS3/0/0 via 10.3.1.2/32
valid cached adjacency
tag rewrite with PO3/0/0, point2point, tags imposed: {42 38}

If a prefix is learned across the sham-link and the path via the sham-link is selected as the best, the PE router does not generate an MP-BGP update for the prefix. It is not possible to route traffic from one sham-link over another sham-link.

In the following example, PE-2 shows how an MP-BGP update for the prefix is not generated. Although 10.3.1.7/32 has been learned via OSPF across the sham-link as shown in bold, no local generation of a route into BGP is performed. The only entry within the BGP table is the MP-BGP update received from PE-3 (the egress PE router for the 10.3.1.7/32 prefix).

PE-2# show ip route vrf ospf 10.3.1.7
Routing entry for 10.3.1.7/32
Known via "ospf 100
", distance 110, metric 12, type intra area
Redistributing via bgp 215
Last update from 10.3.1.2 00:00:10 ago
Routing Descriptor Blocks:
* 10.3.1.2 (Default-IP-Routing-Table), from 10.3.1.7, 00:00:10 ago
Route metric is 12, traffic share count is 1
PE-2# show ip bgp vpnv4 all 10.3.1.7
BGP routing table entry for 100:251:10.3.1.7/32, version 166
Paths: (1 available, best #1)
Not advertised to any peer
Local
10.3.1.2 (metric 30) from 10.3.1.2 (10.3.1.2)
Origin incomplete, metric 11, localpref 100, valid, internal,
best
Extended Community: RT:1:793 OSPF DOMAIN ID:0.0.0.100 OSPF
RT:1:2:0 OSPF 2

The PE router uses the information received from MP-BGP to set the ongoing label stack of incoming packets, and to decide to which egress PE router to label switch the packets.

Benefits

Client Site Connection Across the MPLS VPN Backbone

A sham-link overcomes the OSPF default behavior for selecting an intra-area backdoor route between VPN sites instead of an interarea (PE-to-PE) route. A sham-link ensures that OSPF client sites that share a backdoor link can communicate over the MPLS VPN backbone and participate in VPN services.

Flexible Routing in an MPLS VPN Configuration

In an MPLS VPN configuration, the OSPF cost configured with a sham-link allows you to decide if OSPF client site traffic will be routed over a backdoor link or through the VPN backbone.

Restrictions

When OSPF is used as a protocol between PE and CE routers, the OSPF metric is preserved when routes are advertised over the VPN backbone. The metric is used on the remote PE routers to select the correct route. For this reason, you should not modify the metric value when OSPF is redistributed to BGP, and when BGP is redistributed to OSPF. If you modify the metric value, routing loops may occur.

Related Features and Technologies

- MPLS

- OSPF

- BGP

Related Documents

- Cisco IOS IP Routing: OSPF Command Reference

- "MPLS Virtual Private Networks" module

- "Configuring OSPF" module

- Cisco IOS IP Routing: BGP Configuration Guide, Release 15.0

- RFC 1163, A Border Gateway Protocol

- RFC 1164, Application of the Border Gateway Protocol in the Internet

- RFC 2283, Multiprotocol Extensions for BGP-4

- RFC 2328, Open Shortest Path First, Version 2

- RFC 2547, BGP/MPLS VPNs

Supported Platforms

- Cisco 1400 series

- Cisco 1600

- Cisco 1600R

- Cisco 1710

- Cisco 1720

- Cisco 1721

- Cisco 1750

- Cisco 1751

- Cisco 2420

- Cisco 2600

- Cisco 2691

- Cisco 3620

- Cisco 3631

- Cisco 3640

- Cisco 3660

- Cisco 3725

- Cisco 3745

- Cisco 7100

- Cisco 7200

- Cisco 7500

- Cisco 7700

- URM

- Cisco uBR7200

Determining Platform Support Through Cisco Feature Navigator

Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Cisco Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.

Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:

Click Here

Supported Standards MIBs and RFCs

Standards

No new or modified standards are supported by this feature.

MIBs

No new or modified MIBs are supported by this feature.

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

Click Here

RFCs

No new or modified RFCs are supported by this feature.

Prerequisites

Before you can configure a sham-link in an MPLS VPN, you must first enable OSPF as follows:

- Create an OSPF routing process.

- Specify the range of IP addresses to be associated with the routing process.

- Assign area IDs to be associated with the range of IP addresses.

For more information on these OSPF configuration procedures, go to:

http://www.cisco.com/en/US/docs/ios/iproute_ospf/command/reference/iro_book.html

Configuration Tasks

See the following sections for configuration tasks for the sham-link feature. Each task in the list is identified as either required or optional.

- Creating a Sham-Link (required)

- Verifying Sham-Link Creation (optional)

- Creating a Sham-Link

- Verifying Sham-Link Creation

Creating a Sham-Link

Before You Begin

Before you create a sham-link between PE routers in an MPLS VPN, you must:

- Configure a new interface with a /32 address on the remote PE so that OSPF packets can be sent over the VPN backbone to the remote end of the sham-link. The /32 address must meet the following criteria:

- Belong to a VRF.

- Not be advertised by OSPF.

- Be advertised by BGP.

You can use the /32 address for other sham-links.

- Associate the sham-link with an existing OSPF area.

SUMMARY STEPS

1.    Router1# configure terminal

2.    Router1(config)# interface loopback interface-number

3.    Router1(config-if)# ip vrf forwarding vrf-name

4.    Router1(config-if)# ip address ip-address mask

5.    Router1(config)# end

6.    Router2# configure terminal

7.    Router2(config)# interface loopback interface-number

8.    Router2(config-if)# ip vrf forwarding vrf-name

9.    Router2(config-if)# ip address ip-address mask

10.    Router1(config)# end

11.    Router1(config)# router ospf process-id vrf vrf-name

12.    Router1(config-if)# areaarea-id sham-linksource-address destination-address cost number

13.    Router2(config)# router ospf process-id vrf vrf-name

14.    Router2(config-if)# area area-id sham-link source-address destination-address cost number

DETAILED STEPS

Command or Action

Purpose

Step 1

Router1# configure terminal

Enters global configuration mode on the first PE router.

Step 2

Router1(config)# interface loopback interface-number

Creates a loopback interface to be used as an endpoint of the sham-link on PE-1 and enters interface configuration mode.

Step 3

Router1(config-if)# ip vrf forwarding vrf-name

Associates the loopback interface with a VRF. Removes the IP address.

Step 4

Router1(config-if)# ip address ip-address mask

Reconfigures the IP address of the loopback interface on PE-1.

Step 5

Router1(config)# end

Returns to EXEC mode.

Step 6

Router2# configure terminal

Enters global configuration mode on the second PE router.

Step 7

Router2(config)# interface loopback interface-number

Creates a loopback interface to be used as the endpoint of the sham-link on PE-2 and enters interface configuration mode.

Step 8

Router2(config-if)# ip vrf forwarding vrf-name

Associates the second loopback interface with a VRF. Removes the IP address.

Step 9

Router2(config-if)# ip address ip-address mask

Reconfigures the IP address of the loopback interface on PE-2.

Step 10

Router1(config)# end

Returns to EXEC mode.

Step 11

Router1(config)# router ospf process-id vrf vrf-name

Configures the specified OSPF process with the VRF associated with the sham-link interface on PE-1 and enters interface configuration mode.

Step 12

Router1(config-if)# areaarea-id sham-linksource-address destination-address cost number

Configures the sham-link on the PE-1 interface within a specified OSPF area and with the loopback interfaces specified by the IP addresses as endpoints. cost number configures the OSPF cost for sending an IP packet on the PE-1 sham-link interface.

Step 13

Router2(config)# router ospf process-id vrf vrf-name

Configures the specified OSPF process with the VRF associated with the sham-link interface on PE-2 and enters interface configuration mode.

Step 14

Router2(config-if)# area area-id sham-link source-address destination-address cost number

Configures the sham-link on the PE-2 interface within a specified OSPF area and with the loopback interfaces specified by the IP addresses as endpoints. cost number configures the OSPF cost for sending an IP packet on the PE-2 sham-link interface.

Verifying Sham-Link Creation

To verify that the sham-link was successfully created and is operational, use the show ip ospf sham-links command in EXEC mode:

Router1# show ip ospf sham-links
Sham Link OSPF_SL0 to address 10.2.1.2 is up
Area 1 source address 10.2.1.1
Run as demand circuit
DoNotAge LSA allowed. Cost of using 40 State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40,
Hello due in 00:00:04
Adjacency State FULL (Hello suppressed)
Index 2/2, retransmission queue length 4, number of
retransmission 0
First 0x63311F3C(205)/0x63311FE4(59) Next
0x63311F3C(205)/0x63311FE4(59)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec
Link State retransmission due in 360 msec

Monitoring and Maintaining a Sham-Link

Command

Purpose

Router# show ip ospf sham-links

Displays the operational status of all sham-links configured for a router.

Router# show ip ospf data router  ip-address

Displays information about how the sham-link is advertised as an unnumbered point-to-point connection between two PE routers.

Configuration Examples

The following example shows how to configure a sham-link between two PE routers:

Router1(config)
# interface loopback 1
Router1(config-if)# ip vrf forwarding ospf
Router1(config-if)# ip address 10.2.1.1 255.255.255.255
!
Router2(config)# interface loopback 1
Router2(config-if)# ip vrf forwarding ospf
Router2(config-if)# ip address 10.2.1.2 255.255.255.255
!
Router1(config)# router ospf 100 vrf ospf
Router1(config-if)# area 1 sham-link 10.2.1.1 10.2.1.2 cost 40
!
Router2(config)# router ospf 100 vrf ospf
Router2(config-if)# area 1 sham-link 10.2.1.2 10.2.1.1 cost 40

Glossary

BGP --Border Gateway Protocol. Interdomain routing protocol that exchanges reachability information with other BGP systems. It is defined in RFC 1163.

CE router --customer edge router. A router that is part of a customer network and that interfaces to a provider edge (PE) router. CE routers are not aware of associated VPNs.

CEF -- Cisco Express Forwarding. An advanced Layer 3 IP switching technology. CEF optimizes network performance and scalability for networks with large and dynamic traffic patterns.

OSPF --Open Shortest Path First protocol.

IGP --Interior Gateway Protocol. An Internet protocol used to exchange routing information within an autonomous system. Examples of common IGPs include IGRP, OSPF, and RIP.

LSA --link-state advertisement. A broadcast packet used by link-state protocols. The LSA contains information about neighbors and path costs and is used by the receiving router to maintain a routing table.

MPLS --Multiprotocol Label Switching. Emerging industry standard upon which tag switching is based.

PE router --provider edge router. A router that is part of a service provider network connected to a customer edge (CE) router. All VPN processing occurs in the PE router.

SPF --shortest path first calculation.

VPN --Virtual Private Network. A secure IP-based network that shares resources on one or more physical networks. A VPN contains geographically dispersed sites that can communicate securely over a shared backbone.

VRF --VPN routing and forwarding instance. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table. In general, a VRF includes the routing information that defines a customer VPN site that is attached to a PE router.

Chapter 10. OSPF Retransmissions Limit

The OSPF Retransmissions Limit feature adds a limit to the number of retransmissions of database exchange and update packets for both demand and non-demand circuits. The retransmission of these packets stops once this retry limit is reached, thus preventing unnecessary use of the link in continual retransmission of the packets if, for some reason, a neighbor is not responding during adjacency forming. This feature module describes the change in how the Open Shortest Path First (OSPF) protocol handles retransmissions.

- Finding Feature Information

- Restrictions For OSPF Retransmissions Limit

- Information About OSPF Retransmissions Limit

- Overview About OSPF Retransmissions Limit

- How to Configure OSPF Retransmissions Limit

- Configuration Examples for OSPF Retransmissions Limit

- Additional References for OSPF Retransmissions Limit

- Feature Information for OSPF Retransmissions Limit

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Restrictions For OSPF Retransmissions Limit

The limit to the number of retransmissions does not apply for update packets on nonbroadcast multiaccess (NBMA) point-to-multipoint direct circuits. In this situation, the dead timer is used to end communication with non-responding neighbors and thus stop the retransmissions.

Information About OSPF Retransmissions Limit

Overview About OSPF Retransmissions Limit

Cisco IOS Release 12.2(4)T added a limit to the number of retransmissions of database exchange and update packets for both demand and non-demand circuits. The retransmission of these packets stops once this retry limit is reached, thus preventing unnecessary use of the link in continual retransmission of the packets if, for some reason, a neighbor is not responding during adjacency forming.

The limit for both demand circuit and non-demand circuit retransmissions is 24.

The limit-retransmissions command allows you to either remove (disable) the limit or change the maximum number of retransmissions to be a number from 1 to 255.

- Benefits

Benefits

The limit-retransmissions command provides for backward compatibility for previous or other releases of Cisco IOS or other routers that do not have this feature.

How to Configure OSPF Retransmissions Limit

- Setting OSPF Retransmission Limits

Setting OSPF Retransmission Limits

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-ID

4.    limit retransmissions{[dc {max-number | disable}] [non-dc {max-number | disable}]}

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-ID

Example:

Device(config)# router ospf 18

Configures OSPF routing process and enters OSPF router configuration mode.

Step 4

limit retransmissions{[dc {max-number | disable}] [non-dc {max-number | disable}]}

Example:

Device(config-router)# limit retransmissions dc 5

Sets the limit in the number of retransmissions of database exchange and update packets for both demand and non-demand circuits.

Step 5

end

Example:

Device(config-router)# end

Exits address router configuration mode and returns to privileged EXEC mode.

Configuration Examples for OSPF Retransmissions Limit

- Example: Configuring OSPF Retransmissions Limit

Example: Configuring OSPF Retransmissions Limit

router ospf 18
limit retransmissions dc 5

Additional References for OSPF Retransmissions Limit

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Configuring OSPF

IP Routing: OSPF Configuration Guide

OSPF Commands

IP Routing: OSPF Command Reference

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Retransmissions Limit

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Retransmissions Limit

Feature Name

Releases

Feature Information

OSPF Retransmissions Limit

12.2(11)T

15.2(1)SY

The OSPF Retransmissions Limit feature adds a limit to the number of retransmissions of database exchange and update packets for both demand and non-demand circuits. The retransmission of these packets stops once this retry limit is reached, thus preventing unnecessary use of the link in continual retransmission of the packets if, for some reason, a neighbor is not responding during adjacency forming. .

The following commands were introduced or modified: limit retransmissions .

Chapter 11. OSPF Support for Multi-VRF on CE Routers

The OSPF Support for Multi-VRF on CE Routers feature provides the capability of suppressing provider edge (PE) checks that are needed to prevent loops when the PE is performing a mutual redistribution of packets between the OSPF and BGP protocols. When VPN routing and forward (VRF) is used on a router that is not a PE (that is, one that is not running BGP), the checks can be turned off to allow for correct population of the VRF routing table with routes to IP prefixes.

OSPF multi-VRF allows you to split the router into multiple virtual routers, where each router contains its own set of interfaces, routing table, and forwarding table.

- Finding Feature Information

- Information About OSPF Support for Multi-VRF on CE Routers

- How to Configure OSPF Support for Multi-VRF on CE Routers

- Configuration Examples for OSPF Support for Multi-VRF on CE Routers

- Additional References

- Feature Information for OSPF Support for Multi-VRF on CE Routers

- Glossary

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPF Support for Multi-VRF on CE Routers

The OSPF Support for Multi-VRF on CE Routers feature provides the capability of suppressing provider edge (PE) checks that are needed to prevent loops when the PE is performing a mutual redistribution of packets between the OSPF and BGP protocols. When VPN routing and forward (VRF) is used on a router that is not a PE (that is, one that is not running BGP), the checks can be turned off to allow for correct population of the VRF routing table with routes to IP prefixes.

OSPF multi-VRF allows you to split the router into multiple virtual routers, where each router contains its own set of interfaces, routing table, and forwarding table. OSPF multi-VRF gives you the ability to segment parts of your network and configure those segments to perform specific functions, yet still maintain correct routing information.

How to Configure OSPF Support for Multi-VRF on CE Routers

- Configuring the Multi-VRF Capability for OSPF Routing

- Verifying the OSPF Multi-VRF Configuration

Configuring the Multi-VRF Capability for OSPF Routing

Before You Begin

CEF must be running on the network.

SUMMARY STEPS

1.    enable

2.    show ip ospf [process-id]

3.    configure terminal

4.    router ospf process-id [vrf vpn-name]

5.    capability vrf-lite

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables higher privilege levels, such as privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ip ospf [process-id]

Example:

Router> show ip ospf 1

Displays the status of the router. If the display indicates that the router is connected to the VPN backbone, you can use the capability vrf-lite command to decouple the PE router from the VPN backbone.

Step 3

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 4

router ospf process-id [vrf vpn-name]

Example:

Router(config)# router ospf 1 vrf grc

Enables OSPF routing and enters router configuration mode.

- The process-id argument identifies the OSPF process.

- Use the vrf keyword and vpn-name argument to identify a VPN.

Step 5

capability vrf-lite

Example:

Router(config)# capability vrf-lite

Applies the multi-VRF capability to the OSPF process.

Verifying the OSPF Multi-VRF Configuration

No specific debug or show commands are associated with this feature. You can verify the success of the OSPF multi-VRF configuration by using the show ip ospf[process-id] command to verify that the router is not connected to the VPN backbone.

This output from the show ip ospf processcommand indicates that the PE router is currently connected to the backbone.

Router# show ip ospf 12
Routing Process "ospf 12" with ID 151.1.1.1 and Domain ID 0.0.0.12
Supports only single TOS(TOS0) routes
Supports opaque LSA
Connected to MPLS VPN Superbackbone
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
Number of external LSA 0. Checksum Sum 0x0
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 0. 0 normal 0 stub 0 nssa
External flood list length 0

When the OSPF VRF process is configured with the capability vrf-lite command under the router ospf command, the "Connected to MPLS VPN Superbackbone" line will not be present in the display.

Configuration Examples for OSPF Support for Multi-VRF on CE Routers

- Example Configuring the Multi-VRF Capability

- Example Verifying the OSPF Multi-VRF Configuration

Example Configuring the Multi-VRF Capability

This example shows a basic OSPF network with a VRF named grc configured. The capability vrf-lite command is entered to suppress the PE checks.

!
ip cef
ip vrf grc
rd 1:1
interface Serial2/0
ip vrf forwarding grc
ip address 192.168.1.1 255.255.255.252
!
interface Serial3/0
ip vrf forwarding grc
ip address 192.168.2.1 255.255.255.252
...
!
router ospf 9000 vrf grc
log-adjacency-changes
capability vrf-lite
redistribute rip metric 1 subnets
network 192.168.1.0 0.0.0.255 area 0
!
router rip
address-family ipv4 vrf grc
redistribute ospf 9000 vrf grc
network 192.168.2.0
no auto-summary
end
Device# show ip route vrf grc
Routing Table: grc
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
O IA 192.168.192.0/24 [110/138] via 192.168.1.13, 00:06:08, Serial2/0
[110/138] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.242.0/24 [110/74] via 192.168.1.13, 00:06:08, Serial2/0
O IA 192.168.193.0/24 [110/148] via 192.168.1.13, 00:06:08, Serial2/0
[110/148] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.128.0/24 [110/74] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.129.0/24 [110/84] via 192.168.1.9, 00:06:08, Serial3/0
O IA 192.168.130.0/24 [110/84] via 192.168.1.9, 00:06:08, Serial3/0
172.16.0.0/24 is subnetted, 2 subnets
O E2    172.16.9.0 [110/5] via 192.168.1.13, 00:06:08, Serial2/0
O E2    172.16.10.0 [110/5] via 192.168.1.13, 00:06:08, Serial2/0
O IA 192.168.131.0/24 [110/94] via 192.168.1.9, 00:06:20, Serial3/0
192.168.1.0/30 is subnetted, 4 subnets
C       192.168.1.8 is directly connected, Serial3/0
C       192.168.1.12 is directly connected, Serial2/0
O       192.168.1.0 [110/128] via 192.168.1.9, 00:06:20, Serial3/0
O       192.168.1.4 [110/128] via 192.168.1.13, 00:06:20, Serial2/0

Example Verifying the OSPF Multi-VRF Configuration

This example illustrates the output display from the show ip ospf command after OSPF multi-VRF has been configured on the router.

Device# show ip ospf 9000

Routing Process "ospf 9000" with ID 10.0.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Supports NSSA (compatible with RFC 3101)
Event-log disabled
It is an autonomous system boundary router
Redistributing External Routes from,
rip with metric mapped to 1, includes subnets in redistribution
Router is not originating router-LSAs with maximum metric
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Incremental-SPF disabled
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 0. Checksum Sum 0x000000
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Number of areas transit capable is 0
External flood list length 0
IETF NSF helper support enabled
Cisco NSF helper support enabled
Reference bandwidth unit is 100 mbps
Area BACKBONE(0) (Inactive)
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm last executed 00:00:10.264 ago
SPF algorithm executed 1 times
Area ranges are
Number of LSA 1. Checksum Sum 0x00B674
Number of opaque link LSA 0. Checksum Sum 0x000000
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0

Additional References

Related Documents

Related Topic

Document Title

Configuring OSPF

Configuring OSPF

Multiprotocol Label Switching (MPLS)

MPLS Multi-VRF (VRF Lite) Support

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIBs

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Support for Multi-VRF on CE Routers

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Support for Multi-VRF on CE Routers

Feature Name

Releases

Feature Information

OSPF Support for Multi-VRF on CE Routers

12.0(21)ST

12.0(22)S

12.2(8)B

12.2(13)T

12.2(14)S

The OSPF Support for Multi-VRF on CE Routers feature provides the capability to suppress provider edge (PE) checks that are needed to prevent loops when the PE is performing a mutual redistribution of packets between the OSPF and BGP protocols. When VPN routing and forwarding (VRF) is used on a router that is not a PE (that is, one that is not running BGP), the checks can be turned off to allow for correct population of the VRF routing table with routes to IP prefixes.

The following commands are introduced or modified in the feature documented in this module:

- capability vrf-lite

Glossary

CE Router --Customer Edge router, an edge router in the C network, defined as a C router which attaches directly to a P router.

C Network --Customer (enterprise or service provider) network.

C Router --Customer router, a router in the C network.

LSA --link-state advertisement . Broadcast packet used by link-state protocols that contains information about neighbors and path costs. LSAs are used by the receiving routers to maintain their routing tables.

PE Router --Provider Edge router, an edge router in the P network, defined as a P router which attaches directly to a C router.

P Network --MPLS-capable service provider core network. P routers perform MPLS.

P Router --Provider router, a router in the P network.

SPF --shortest path first. A routing algorithm that iterates on length of path to determine a shortest-path spanning tree.

VPN --Virtual Private Network. Enables IP traffic to travel securely over a public TCP/IP network by encrypting all traffic from one network to another.

VRF --VPN Routing and Forwarding.

Chapter 12. OSPFv2 Multiarea Adjacency

This module describes how to configure multiarea adjacency for Open Shortest Path First version 2 (OSPFv2). You can add more than one area to an existing OSPFv2 primary interface. The additional logical interfaces support multiarea adjacency.

- Finding Feature Information

- Prerequisites for OSPFv2 Multiarea Adjacency

- Restrictions for OSPFv2 Multiarea Adjacency

- Information About OSPFv2 Multiarea Adjacency

- How to Configure OSPFv2 Multiarea Adjacency

- Configuration Examples for OSPFv2 Multiarea Adjacency

- Additional References for OSPFv2 Multiarea Adjacency

- Feature Information for OSPFv2 Multiarea Adjacency

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv2 Multiarea Adjacency

- Ensure that Open Shortest Path First (OSPF) is configured on the primary interface.

- Ensure that the primary interface type is point-to-point.

Restrictions for OSPFv2 Multiarea Adjacency

A multiarea interface has the following restrictions.

- Operates only if OSPF is configured on the primary interface.

- Exists as a logical construct over a primary interface for OSPF; however, the neighbor state on the primary interface is independent of the multiarea interface.

- Establishes a neighbor relationship with the corresponding multiarea interface on the neighboring device. A mixture of multiarea and primary interfaces is not supported.

- Advertises an unnumbered point-to-point link in the device link-state advertisement (LSA) for the corresponding area when the neighbor state is full.

- Inherits all the OSPF parameters (such as, authentication) from the primary interface. You cannot configure the parameters on a multiarea interface; however, you can configure the parameters on the primary interface.

Information About OSPFv2 Multiarea Adjacency

- OSPFv2 Multiarea Adjacency Overview

OSPFv2 Multiarea Adjacency Overview

The Open Shortest Path First (OSPF) protocol allows you to divide a network topology into separate areas. The interface on which OSPF is configured belongs to only one area at any given point of time. This causes suboptimal routing for certain topologies, due to intra-area route preference over the interarea routes.

Open Shortest Path First version 2 (OSPFv2) allows a single physical link to be shared by multiple areas. This creates an intra-area path in each of the corresponding areas sharing the same link. All areas have an interface on which OSPF is configured. One of these interfaces is designated as the primary interface and others as secondary interfaces.

The OSPFv2 Multiarea Adjacency feature allows you to configure a link on the primary interface to enable optimized routing in multiple areas. Each multiarea interface is announced as a point-to-point unnumbered link. The multiarea interface exists as a logical construct over an existing primary interface. The neighbor state on the primary interface is independent of the neighbor state of the multiarea interface. The multiarea interface establishes a neighbor relationship with the corresponding multiarea interface on the neighboring device. You can only configure multiarea adjacency on an interface that has two OSPF speakers. In case of native broadcast networks, the interface must be configured as an OSPF point-to-point type to enable the interface for multiarea adjacency.

Use the ip ospf multi-area command to configure multiarea adjacency on the primary OSPFv2 interface.

How to Configure OSPFv2 Multiarea Adjacency

- Configuring OSPFv2 Multiarea Adjacency

Configuring OSPFv2 Multiarea Adjacency

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ip address ip-address mask

5.    ip ospf proces-id area area-id

6.    ip ospf network point-to-point

7.    ip ospf multi-area multi-area-id

8.    ip ospf multi-area multi-area-id cost interface-cost

9.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface Ethernet 0/0

Specifies an interface and enters interface configuration mode.

Step 4

ip address ip-address mask

Example:

Device(config)# ip address 10.0.12.1 255.255.255.0

Assigns an IP address to this interface.

Step 5

ip ospf proces-id area area-id

Example:

Device (config-if)# ip ospf 10 area 8

Configures the primary OSPF interface.

- The process-id argument identifies the OSPF process. The range is from 1 to 65535.

- The area-id argument identifies the OSPF area. The range is from 0 to 4294967295, or you can use an IP address.

Step 6

ip ospf network point-to-point

Example:

Device (config-if)# ip ospf network point-to-point

Specifies the primary interface type as point-to-point.

Step 7

ip ospf multi-area multi-area-id

Example:

Device (config-if)# ip ospf multi-area 11

Configures multiarea adjacency on the interface.

- The multi-area-id argument identifies the OSPF multiarea. The range is from 0 to 4294967295, or you can use an IP address.

Step 8

ip ospf multi-area multi-area-id cost interface-cost

Example:

Device (config-if)# ip ospf multi-area 11 cost 10

(Optional) Specifies the cost of sending a packet on an Open Shortest Path First (OSPF) multiarea interface,

Step 9

end

Example:

Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Configuration Examples for OSPFv2 Multiarea Adjacency

- Example: Configuring OSPFv2 Multiarea Adjacency

Example: Configuring OSPFv2 Multiarea Adjacency

Device# enable
Device# configure terminal
Device(config)# interface Ethernet 0/0
Device (config-if)# ip address 10.0.12.1 255.255.255.0
Device (config-if)# ip ospf 1 area 0
Device (config-if)# ip ospf network point-to-point
Device (config-if)# ip ospf multi-area 2
Device (config-if)# ip ospf multi-area 2 cost 10
Device (config-if)# end

The following is a sample output from the show ip ospf 2 multi-area command.

Device# show ip ospf 2 multi-area

OSPF_MA1 is up, line protocol is up
Primary Interface Ethernet0/0, Area 2
Interface ID 2
MTU is 1500 bytes
Neighbor Count is 1

The following is a sample output from the show ip ospf interface command.

Device# show ip ospf interface

Ethernet0/0 is up, line protocol is up
Internet Address 10.0.12.1/24, Area 0, Attached via Interface Enable
Process ID 1, Router ID 10.0.0.2, Network Type POINT_TO_POINT, Cost: 10
Topology-MTID    Cost    Disabled    Shutdown      Topology Name
0           10        no          no            Base
Enabled by interface config, including secondary ip addresses
Transmit Delay is 1 sec, State POINT_TO_POINT
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:06
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Can be protected by per-prefix Loop-Free FastReroute
Can be used for per-prefix Loop-Free FastReroute repair paths
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.0.0.1
Suppress hello for 0 neighbor(s)
Multi-area interface Count is 1
OSPF_MA1 interface exists in area 2 Neighbor Count is 1
OSPF_MA1 is up, line protocol is up
Interface is unnumbered. Using address of Ethernet0/0 (10.0.12.1), Area 2, Attached via Multi-area
Process ID 1, Router ID 10.0.0.2, Network Type POINT_TO_POINT, Cost: 10
Topology-MTID    Cost    Disabled    Shutdown      Topology Name
0           10        no          no            Base
Transmit Delay is 1 sec, State POINT_TO_POINT
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:06
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Can be protected by per-prefix Loop-Free FastReroute
Can be used for per-prefix Loop-Free FastReroute repair paths
Index 1/3, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 2
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.0.0.1
Suppress hello for 0 neighbor(s)

Additional References for OSPFv2 Multiarea Adjacency

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Protocol-independent features that work with OSPF

“Configuring IP Routing Protocol-Independent Features” module

RFCs

RFC

Title

RFC 5185

OSPF Multi-Area Adjacency, May 2008

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv2 Multiarea Adjacency

Feature Information for OSPFv2 Multiarea Adjacency

Feature Name

Releases

Feature Information

OSPFv2 Multiarea Adjacency

15.4(1)T

OSPFv2 multiarea adjacency allows you to configure a link on the primary interface in multiple OSPF areas to enable optimized routing.

The following commands were modified:ip ospf multi-area, ip ospf multi-area cost, and show ip ospf multi-area.

Chapter 13. OSPFv2 Autoroute Exclude

The OSPFv2 Autoroute Exclude feature allows specific destinations and prefixes to avoid Traffic Engineering (TE) tunnels for the packet transport. The rest of the prefixes can still be set to use TE tunnels. Prefixes that are excluded do not use a TE tunnel path. Only native non-TE paths are downloaded to RIB for such routes. This module describes how to configure the OSPFv2 Autoroute Exclude feature.

- Finding Feature Information

- Prerequisites for OSPFv2 Autoroute Exclude

- Information About OSPFv2 Autoroute Exclude

- How to Configure OSPFv2 Autoroute Exclude

- Configuration Examples for OSPFv2 Autoroute Exclude

- Additional References for OSPFv2 Autoroute Exclude

- Feature Information for OSPFv2 Autoroute Exclude

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv2 Autoroute Exclude

- Open Shortest Path First (OSPF) must be configured in your network.

- Cisco Express Forwarding (CEF) must be enabled.

- Multiprotocol Label Switching (MPLS) TE tunnels must be configured.

Information About OSPFv2 Autoroute Exclude

- Overview of OSPFv2 Autoroute Exclude

Overview of OSPFv2 Autoroute Exclude

The Autoroute feature is an IP routing method that forces OSPF to use MPLS TE tunnels to build paths for IP traffic routes.

The Autoroute feature enables all routes to use TE Tunnels, even if there is an alternate non-TE path available for that route.

The OSPFv2 Autoroute Exclude feature allows specific destinations or prefixes to avoid TE tunnels, while other prefixes can still be configured to use TE tunnels. Prefixes that are excluded do not use a TE tunnel path. Only native non-TE paths are downloaded to RIB for such routes.

The auto route exclude option is configured under the router OSPF configuration mode by using a prefix list. IP addresses and prefixes that are members of this prefix list are excluded from TE tunnels, even when the auto route is enabled on them. If the IP addresses or prefixes are added to the prefix list, they are dynamically routed without passing through the TE tunnel. If the IP addresses or prefixes are removed from the prefix list, they are dynamically rerouted back on the TE tunnel path.

How to Configure OSPFv2 Autoroute Exclude

- Configuring OSPFv2 Autoroute Exclude

Configuring OSPFv2 Autoroute Exclude

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-ID

4.    router-id ip-address

5.    mpls traffic-eng router-id interface-name

6.    mpls traffic-eng areanumber

7.    mpls traffic-eng autoroute-exclude prefix-list prefix-list-name

8.    exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-ID

Example:

Device(config)# router ospf 18

Configures OSPF routing process and enters OSPF router configuration mode.

Step 4

router-id ip-address

Example:

Device(config-router)# router-id 10.1.1.1

Enables to use a fixed router ID in router configuration mode.

Step 5

mpls traffic-eng router-id interface-name

Example:

Device(config-router)# mpls traffic-eng router-id Loopback0

Specifies the traffic engineering router identifier for the node and the IP address associated with a given interface.

Step 6

mpls traffic-eng areanumber

Example:

Device(config-router)# mpls traffic-eng area 0

Configures a router running OSPF MPLS so that it floods traffic engineering for the indicated OSPF area.

Step 7

mpls traffic-eng autoroute-exclude prefix-list prefix-list-name

Example:

Device(config-router)# mpls traffic-eng autoroute-exclude prefix-list kmd

Allows specific destinations and prefixes to avoid routing through TE tunnels.

- Prefixes that are excluded do not use a TE tunnel path.

Step 8

exit

Example:

Device(config-router)# exit

Exits router configuration mode and returns to privileged EXEC mode.

Configuration Examples for OSPFv2 Autoroute Exclude

- Example: Configuring OSPFv2 Autoroute Exclude

Example: Configuring OSPFv2 Autoroute Exclude

!
router ospf 1
router-id 3.3.3.3
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
mpls traffic-eng autoroute-exclude prefix-list XX

!

Additional References for OSPFv2 Autoroute Exclude

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Configuring OSPF

IP Routing: OSPF Configuration Guide

Configuring Basic Cisco Express Forwarding

IP Switching: Cisco Express Forwarding Configuration Guide

MPLS Traffic Engineering Tunnel Source

MPLS Traffic Engineering Path Calculation and Setup Configuration Guide

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv2 Autoroute Exclude

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv2 Autoroute Exclude

Feature Name

Releases

Feature Information

OSPFv2 Autoroute Exclude

15.5(1)T

The OSPFv2 Autoroute Exclude feature allows specific destinations and prefixes to avoid TE tunnels for the packet transport.

The following commands were introduced or modified: mpls traffic-eng autoroute-exclude prefix list.

Chapter 14. OSPFv3 Multiarea Adjacency

The OSPFv3 Multiarea Adjacency feature allows you to configure a link that multiple Open Shortest Path First version 3 (OSPFv3) areas can share to enable optimized routing. You can add more than one area to an existing OSPFv3 primary interface.

- Finding Feature Information

- Prerequisites for OSPFv3 Multiarea Adjacency

- Restrictions for OSPFv3 Multiarea Adjacency

- Information About OSPFv3 Multiarea Adjacency

- How to Configure OSPFv3 Multiarea Adjacency

- Verifying OSPFv3 Multiarea Adjacency

- Configuration Examples for OSPFv3 Multiarea Adjacency

- Additional References for OSPFv3 Multiarea Adjacency

- Feature Information for OSPFv3 Multiarea Adjacency

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv3 Multiarea Adjacency

- Ensure that Open Shortest Path First version 3 (OSPFv3) is configured on the primary interface.

- Ensure that the primary interface type is point-to-point.

Restrictions for OSPFv3 Multiarea Adjacency

- A multiarea interface operates only if OSPFv3 is configured on the primary interface and the OSPFv3 network type of the primary interface is point-to-point.

- A multiarea interface exists as a logical construct over a primary interface for OSPFv3; however, the neighbor state on the primary interface is independent of the multiarea interface.

- A multiarea interface establishes a neighbor relationship with the corresponding multiarea interface on the neighboring device. A mixture of multiarea and primary interfaces is not supported.

- A multiarea interface advertises a point-to-point connection to another device in the device link-state advertisement (LSA) for the corresponding area when the neighbor state is full.

- A multiarea interface inherits all the OSPFv3 parameters (such as, authentication) from the primary interface. You cannot configure the parameters on a multiarea interface; however, you can configure the parameters on the primary interface.

Information About OSPFv3 Multiarea Adjacency

- OSPFv3 Multiarea Adjacency Overview

OSPFv3 Multiarea Adjacency Overview

Open Shortest Path First version 3 (OSPFv3) allows a single physical link to be shared by multiple areas. This creates an intra-area path in each of the corresponding areas sharing the same link. All areas have an interface on which you can configure OSPFv3. One of these interfaces is designated as the primary interface and others as secondary interfaces.

The OSPFv3 Multiarea Adjacency feature allows you to configure a link on the primary interface to enable optimized routing in multiple areas. Each multiarea interface is announced as a point-to-point unnumbered link. The multiarea interface exists as a logical construct over an existing primary interface. The neighbor state on the primary interface is independent of the neighbor state of the multiarea interface. The multiarea interface establishes a neighbor relationship with the corresponding multiarea interface on the neighboring device. You can only configure multiarea adjacency on an interface that has two OSPFv3 speakers.

Use the ospfv3 multi-area command to configure multiarea adjacency on the primary OSPFv3 interface.

How to Configure OSPFv3 Multiarea Adjacency

- Configuring OSPFv3 Multiarea Adjacency

Configuring OSPFv3 Multiarea Adjacency

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ipv6 enable

5.    ospfv3 multi-area multi-area-id

6.    ospfv3 multi-area multi-area-id cost interface-cost

7.    ospfv3 process-id ipv6 area area-id

8.    serial restart-delay count

9.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface serial 2/0

Specifies the interface type and number.

Step 4

ipv6 enable

Example:

Device(config-if)# ipv6 enable

Enables IPv6 processing on an interface that has not been configured with an explicit IPv6 address.

Step 5

ospfv3 multi-area multi-area-id

Example:

Device(config-if)# ospfv3 multi-area 100

Configures multiarea adjacency on the interface.

- The multi-area-id argument identifies the OSPFv3 multiarea. The range is from 0 to 4294967295, or you can use an IP address.

Step 6

ospfv3 multi-area multi-area-id cost interface-cost

Example:

Device(config-if)# ospfv3 multi-area 100 cost 512

(Optional) Specifies the cost of sending a packet on an OSPFv3 multiarea interface. Use this command to specify the cost only if you want the cost of the multiarea interface to be different than the cost of the primary interface.

Step 7

ospfv3 process-id ipv6 area area-id

Example:

Device(config-if)# ospfv3 1 ipv6 area 0

Configures the OSPFv3 interface.

- The process-id argument identifies the OSPF process. The range is from 1 to 65535.

- The area-id argument identifies the OSPF area. The range is from 0 to 4294967295, or you can use an IP address.

Step 8

serial restart-delay count

Example:

Device(config-if)# serial restart-delay 0

Sets the amount of time that the router waits before trying to bring up a serial interface when it goes down. The count argument specifies the frequency (in seconds) at which that hardware is reset. The range is from 0 to 900.

Step 9

end

Example:

Device(config-if)# end

Returns to privileged EXEC mode.

Verifying OSPFv3 Multiarea Adjacency

SUMMARY STEPS

1.    enable

2.    show ospfv3 interface brief

3.    show ospfv3 multi-area

4.    show ospfv3 interface

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ospfv3 interface brief

Example:

Device# show ospfv3 interface brief

Displays brief information about Open Shortest Path First version 3 (OSPFv3) interfaces.

Step 3

show ospfv3 multi-area

Example:

Device# show ospfv3 multi-area

Displays information about OSPFv3 multiarea interfaces.

Step 4

show ospfv3 interface

Example:

Device# show ospfv3 interface

Displays information about OSPFv3 interfaces.

Configuration Examples for OSPFv3 Multiarea Adjacency

- Example: OSPFv3 Multiarea Adjacency Configuration

- Example: Verifying OSPFv3 Multiarea Adjacency

Example: OSPFv3 Multiarea Adjacency Configuration

Device> enable
Device# configure terminal
Device(config)# interface serial 2/0
Device(config-if)# ipv6 enable
Device(config-if)# ospfv3 multi-area 100
Device(config-if)# ospfv3 multi-area 100 cost 512
Device(config-if)# ospfv3 1 ipv6 area 0
Device(config-if)# serial restart-delay 0
Device(config-if)# end

Example: Verifying OSPFv3 Multiarea Adjacency

Sample Output for the show ospfv3 interface brief Command

To display brief information about Open Shortest Path First version 3 (OSPFv3) interfaces, use the show ospfv3 interface brief command in privileged EXEC mode.

Device# show ospfv3 interface brief

Interface PID Area  AF   Cost  State Nbrs F/C
Se2/0     1   0    ipv6  64    P2P   1/1
MA2 1     1   100  ipv6  512   P2P   1/1

To display information about OSPFv3 multiarea interfaces, use the show ospfv3 multi-area command in privileged EXEC mode.

Device# show ospfv3 multi-area

OSPFV3_MA2 is up, line protocol is up
Primary Interface Serial2/0, Area 100
Interface ID 10
MTU is 1500 bytes
Neighbor Count is 1

To display information about OSPFv3 interfaces, use the show ospfv3 interface command in privileged EXEC mode.

Device# show ospfv3 interface

Serial2/0 is up, line protocol is up
Link Local Address 2001:DB8:0:ABCD::1, Interface ID 10
Area 0, Process ID 1, Instance ID 0, Router ID 10.0.0.12
Network Type POINT_TO_POINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_POINT
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:07
Graceful restart helper support enabled
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.0.0.22
Suppress hello for 0 neighbor(s)
Multi-area interface Count is 1
OSPFV3_MA2 interface exists in area 100 Neighbor Count is 1
OSPFV3_MA2 is up, line protocol is up
Link Local Address 2001:DB8:0:ABCD::1, Interface ID 10
Area 100, Process ID 1, Instance ID 0, Router ID 10.0.0.12
Network Type POINT_TO_POINT, Cost: 512
Transmit Delay is 1 sec, State POINT_TO_POINT
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:08
Graceful restart helper support enabled
Index 1/1/2, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.0.0.22

Additional References for OSPFv3 Multiarea Adjacency

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 Multiarea Adjacency

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Name

Releases

Feature Information

OSPFv3 Multiarea Adjacency

Cisco IOS XE Release 3.11S

The OSPFv3 Multiarea Adjacency feature allows you to configure a link that multiple Open Shortest Path First version 3 (OSPFv3) areas can share to enable optimized routing. You can add more than one area to an existing OSPFv3 primary interface.

Chapter 15. OSPFv3 Authentication Trailer

The OSPFv3 Authentication Trailer feature as specified in RFC 6506 provides a mechanism to authenticate Open Shortest Path First version 3 (OSPFv3) protocol packets as an alternative to existing OSPFv3 IPsec authentication.

- Finding Feature Information

- Information About OSPFv3 Authentication Trailer

- How to Configure OSPFv3 Authentication Trailer

- Configuration Examples for OSPFv3 Authentication Trailer

- Additional References for OSPFv3 Authentication Trailer

- Feature Information for OSPFv3 Authentication Trailer

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPFv3 Authentication Trailer

- Overview of OSPFv3 Authentication Trailer

Overview of OSPFv3 Authentication Trailer

Prior to the OSPFv3 Authentication Trailer, OSPFv3 IPsec as defined in RFC 4552 was the only mechanism for authenticating protocol packets. The OSPFv3 Authentication Trailer feature defines an alternative mechanism to authenticate OSPFv3 protocol packets that additionally provides a packet replay protection via sequence number and does not have any platform dependencies.

To perform non-IPsec cryptographic authentication, OSPFv3 devices append a special data block, that is, Authentication Trailer, to the end of the OSPFv3 packets. The length of the Authentication Trailer is not included in the length of the OSPFv3 packet but is included in the IPv6 payload length. The Link-Local Signaling (LLS) block is established by the L-bit setting in the “OSPFv3 Options” field in OSPFv3 hello and database description packets. If present, the LLS data block is included along with the OSPFv3 packet in the cryptographic authentication computation.

A new Authentication Trailer (AT)-bit is introduced into the OSPFv3 Options field. OSPFv3 devices must set the AT-bit in OSPFv3 Hello and Database Description packets to indicate that all the packets on this link will include an Authentication Trailer. For OSPFv3 Hello and Database Description packets, the AT-bit indicates the AT is present. For other OSPFv3 packet types, the OSPFv3 AT-bit setting from the OSPFv3 Hello/Database Description setting is preserved in the OSPFv3 neighbor data structure. OSPFv3 packet types that do not include an OSPFv3 Options field will use the setting from the neighbor data structure to determine whether or not the AT is expected. The AT-bit must be set in all OSPFv3 Hello and Database Description packets that contain an Authentication Trailer.

To configure the Authentication Trailer, OSPFv3 utilizes existing Cisco IOS key chain command. For outgoing OSPFv3 packets, the following rules are used to select the key from the key chain:

- Select the key that is the last to expire.

- If two keys have the same stop time, select the one with the highest key ID.

The security association (SA) ID maps to the authentication algorithm and the secret key, which is used to generate and verify the message digest. If the authentication is configured but the last valid key is expired, then the packets are sent using the key. A syslog message is also generated. If no valid key is available then the packet is sent without the authentication trailer. When packets are received, the key ID is used to look up the data for that key. If the key ID is not found in the key chain or if the SA is not valid, the packet is dropped. Otherwise, the packet is verified using the algorithm and the key that is configured for the key ID. Key chains support rollover using key lifetimes. A new key can be added to a key chain with the send start time set in the future. This setting allows the new key to be configured on all devices before the keys are actually used.

The hello packets have higher priority than any other OSPFv3 packets and therefore can get re-ordered on the outgoing interface. This reordering can create problems with sequence number verification on neighboring devices. To prevent sequence mismatch, OSPFv3 verifies the sequence number separately for each packet type.

See RFC 6506 for more details on the authentication procedure.

How to Configure OSPFv3 Authentication Trailer

- Configuring OSPFv3 Authentication Trailer

Configuring OSPFv3 Authentication Trailer

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ospfv3 [pid] [ipv4 | ipv6] authentication {key-chain chain-name | null}

5.    router ospfv3 [process-id]

6.    address-family ipv6 unicast vrf vrf-name

7.    area area-id authentication {key-chain chain-name | null}

8.    area area-id virtual-link router-id authentication key-chain chain-name

9.    area area-id sham-link source-address destination-address authentication key-chain chain-name

10.    authentication mode {deployment | normal}

11.    end

12.    show ospfv3 interface

13.    show ospfv3 neighbor [detail]

14.    debug ospfv3 vrf authentication

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface GigabitEthernet 2/0

Specifies the interface type and number.

Step 4

ospfv3 [pid] [ipv4 | ipv6] authentication {key-chain chain-name | null}

Example:

Device(config-if)# ospfv3 1 ipv4 authentication key-chain ospf-1

Specifies the authentication type for an OSPFv3 instance.

Step 5

router ospfv3 [process-id]

Example:

Device(config-if)# router ospfv3 1

Enters OSPFv3 router configuration mode.

Step 6

address-family ipv6 unicast vrf vrf-name

Example:

Device(config-router)# address-family ipv6 unicast vrf vrf1

Configures the IPv6 address family in the OSPFv3 process and enters IPv6 address family configuration mode.

Step 7

area area-id authentication {key-chain chain-name | null}

Example:

Device(config-router-af)# area 1 authentication key-chain ospf-chain-1

Configures the authentication trailer on all interfaces in the OSPFv3 area.

Step 8

area area-id virtual-link router-id authentication key-chain chain-name

Example:

Device(config-router-af)# area 1 virtual-link 1.1.1.1 authentication key-chain ospf-chain-1

Configures the authentication for virtual links.

Step 9

area area-id sham-link source-address destination-address authentication key-chain chain-name

Example:

Device(config-router-af)# area 1 sham-link 1.1.1.1 1.1.1.0 authentication key-chain ospf-chain-1

Configures the authentication for sham links.

Step 10

authentication mode {deployment | normal}

Example:

Device(config-router-af)# authentication mode deployment

Specifies the type of authentication used for the OSPFv3 instance.

- The deployment keyword provides adjacency between configured and unconfigured authentication devices.

Step 11

end

Example:

Device(config-router-af)# end

Exits IPv6 address family configuration mode and returns to privileged EXEC mode.

Step 12

show ospfv3 interface

Example:

Device# show ospfv3

(Optional) Displays OSPFv3-related interface information.

Step 13

show ospfv3 neighbor [detail]

Example:

Device# show ospfv3 neighbor detail

(Optional) Displays OSPFv3 neighbor information on a per-interface basis.

Step 14

debug ospfv3 vrf authentication

Example:

Device# debug ospfv3 vrf authentication

(Optional) Displays debugging information for OSPFv3.

Configuration Examples for OSPFv3 Authentication Trailer

- Example: Configuring OSPFv3 Authentication Trailer

- Example: Verifying OSPFv3 Authentication Trailer

Example: Configuring OSPFv3 Authentication Trailer

interface GigabitEthernet 0/0
ospfv3 1 ipv4 authentication key-chain ospf-1
router ospfv3 1
address-family ipv6 unicast vrf vrf1
area 1 authentication key-chain ospf-1
area 1 virtual-link 1.1.1.1 authentication key-chain ospf-1
area 1 sham-link 1.1.1.1 authentication key-chain ospf-1
authentication mode deployment
!
key chain ospf-1
key 1
key-string ospf
cryptographic-algorithm hmac-sha-512
!

Example: Verifying OSPFv3 Authentication Trailer

The following examples show the output of the show ospfv3 commands.

Device# show ospfv3
OSPFv3 1 address-family ipv6
Router ID 1.1.1.1
…
RFC1583 compatibility enabled
Authentication configured with deployment key lifetime
Active Key-chains:
Key chain mama: Send key 1, Algorithm HMAC-SHA-256, Number of interfaces 1
Area BACKBONE(0)

Device# show ospfv3 neighbor detail

OSPFv3 1 address-family ipv6 (router-id 2.2.2.2)

Neighbor 1.1.1.1
In the area 0 via interface GigabitEthernet0/0
Neighbor: interface-id 2, link-local address FE80::A8BB:CCFF:FE01:2D00
Neighbor priority is 1, State is FULL, 6 state changes
DR is 2.2.2.2 BDR is 1.1.1.1
Options is 0x000413 in Hello (V6-Bit, E-Bit, R-Bit, AT-Bit)
Options is 0x000413 in DBD (V6-Bit, E-Bit, R-Bit, AT-Bit)
Dead timer due in 00:00:33
Neighbor is up for 00:05:07
Last packet authentication succeed
Index 1/1/1, retransmission queue length 0, number of retransmission 0
First 0x0(0)/0x0(0)/0x0(0) Next 0x0(0)/0x0(0)/0x0(0)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec

Device# show ospfv3 interface

GigabitEthernet0/0 is up, line protocol is up
…
Cryptographic authentication enabled
Sending SA: Key 25, Algorithm HMAC-SHA-256 – key chain ospf-keys
Last retransmission scan time is 0 msec, maximum is 0 msec

Additional References for OSPFv3 Authentication Trailer

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Configuring OSPF features

IP Routing: OSPF Configuration Guide

Standards and RFCs

Related Topic

Document Title

RFC for Supporting Authentication Trailer for OSPFv3

RFC 6506

RFC for Authentication/Confidentiality for OSPFv3

RFC 4552

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 Authentication Trailer

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 Authentication Trailer

Feature Name

Releases

Feature Information

OSPFv3 Authentication Trailer

15.4(2)T

The OSPFv3 Authentication Trailer feature as specified in RFC 6506 provides a mechanism to authenticate OSPFv3 protocol packets as an alternative to existing OSPFv3 IPsec authentication.

The following commands were introduced or modified: ospfv3 authentication key-chain, authentication mode, debug ospfv3 vrf authentication.

Chapter 16. OSPFv3 Autoroute Exclude

OSPFv3 Autoroute Exclude feature allows you to use specific destinations and prefix-list to specify a list of prefixes that are routed using native paths instead of TE tunnels for packet transport. The rest of the prefixes can still be set to use TE tunnels. Prefixes that are excluded do not use a TE tunnel path. IPv6 routes over TE tunnels are supported by OSPFv3 using Autoroute Announce (AA) or Forwarding Adjacencies (FA).

This module describes how to configure the OSPFv3 Autoroute Exclude feature.

- Finding Feature Information

- Prerequisites for OSPFv3 Autoroute Exclude

- Information About OSPFv3 Autoroute Exclude

- How to Configure OSPFv3 Autoroute Exclude

- Configuration Examples for OSPFv3 Autoroute Exclude

- Additional References for OSPFv3 Autoroute Exclude

- Feature Information for OSPFv3 Autoroute Exclude

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv3 Autoroute Exclude

- Open Shortest Path First (OSPF) must be configured in your network.

- Cisco Express Forwarding (CEF) must be enabled.

- Multiprotocol Label Switching (MPLS) TE tunnels must be configured.

- Auto route announce and forwarding adjacencies must be configured. You can configure either auto route announce or forwarding adjacencies on an interface. You cannot configure them both on the same interface.

Information About OSPFv3 Autoroute Exclude

- Overview of OSPFv3 Autoroute Exclude

Overview of OSPFv3 Autoroute Exclude

The auto route feature is an IP routing method that forces OSPF to use MPLS TE tunnels to build paths for IP traffic routes. The auto route feature enables all routes to use TE Tunnels, even if there is an alternate non-TE path available for that route.

The OSPFv3 Autoroute Exclude feature allows specific IPv6 destinations or prefixes to avoid TE tunnels, while other prefixes can still be configured to use TE tunnels. Prefixes that are excluded do not use a TE tunnel path. Only native non-TE paths are downloaded to RIB for such routes. IPv6 routes over TE tunnels are supported by OSPFv3 using auto route announce (AA) or forwarding adjacencies (FA).

The auto route exclude option is configured under the router OSPF configuration mode by using a prefix list. IP addresses and prefixes that are members of this prefix list are excluded from TE tunnels, even when the auto route is enabled on them. If the IP addresses or prefixes are added to the prefix list, they are dynamically routed without passing through the TE tunnel. If the IP addresses or prefixes are removed from the prefix list, they are dynamically rerouted back on the TE tunnel path.

See the Autoroute Announce and Forwarding Adjacencies For OSPFv3 module in IP Routing: OSPF Configuration Guide for details on configuring auto route announce and forwarding adjacencies For OSPFv3.

How to Configure OSPFv3 Autoroute Exclude

- Configuring OSPFv3 Autoroute Exclude

Configuring OSPFv3 Autoroute Exclude

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 process-ID

4.    address-family ipv6 unicast

5.    mpls traffic-engineering autoroute-exclude prefix-list prefix-list-name

6.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 process-ID

Example:

Device(config)# router ospfv3 18

Configures OSPFv3 routing process and enters OSPF router configuration mode.

Step 4

address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv6 unicast

Enters IPv6 address family configuration mode for OSPFv3.

Step 5

mpls traffic-engineering autoroute-exclude prefix-list prefix-list-name

Example:

Device(config-router-af)# mpls traffic-engineering autoroute-exclude prefix-list kmd

Allows specific destinations and prefixes to avoid routing through TE tunnels.

- Prefixes that are excluded do not use a TE tunnel path.

Step 6

end

Example:

Device(config-router-af)# end

Exits address family configuration mode and returns to privileged EXEC mode.

Configuration Examples for OSPFv3 Autoroute Exclude

- Example: Configuring OSPFv3 Autoroute Exclude

Example: Configuring OSPFv3 Autoroute Exclude

!
router ospfv3 18
address-family ipv6 unicast
mpls traffic-engineering autoroute-exclude prefix-list kmd

!

Additional References for OSPFv3 Autoroute Exclude

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Configuring OSPF

IP Routing: OSPF Configuration Guide

Autoroute Announce and Forwarding Adjacencies For OSPFv3

IP Routing: OSPF Configuration Guide

Configuring Basic Cisco Express Forwarding

IP Switching: Cisco Express Forwarding Configuration Guide

MPLS Traffic Engineering Tunnel Source

MPLS Traffic Engineering Path Calculation and Setup Configuration Guide

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 Autoroute Exclude

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 Autoroute Exclude

Feature Name

Releases

Feature Information

OSPFv3 Autoroute Exclude

15.5(2)T

OSPFv3 Autoroute Exclude feature allows you to use specific destinations and prefix-list to specify a list of prefixes that are routed using native paths instead of TE tunnels for packet transport. IPv6 routes over TE tunnels are supported by OSPFv3 using autoroute announce or forwarding adjacencies.

The following commands were introduced or modified: mpls traffic-engineering autoroute-exclude prefix list.

Chapter 17. OSPFv2-OSPF Live-Live

The OSPFv2-OSPF Live-Live feature delivers multicast streams over non overlapping paths to various applications. The multicast traffic is split into multiple streams at the beginning of a protected network. All streams flow over non overlapping paths so that when a link failure occurs on one path, multicast traffic is still delivered through other paths. All streams are merged back at the end of the protected network. This module describes how to configure the OSPFv2-OSPF Live-Live feature.

- Finding Feature Information

- Information About OSPFv2-OSPF Live-Live

- How to Configure OSPFv2-OSPF Live-Live

- Configuration Examples for OSPFv2-OSPF Live-Live

- Additional References for OSPFv2-OSPF Live-Live

- Feature Information for OSPFv2-OSPF Live-Live

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPFv2-OSPF Live-Live

- Overview of OSPFv2-OSPF Live-Live

Overview of OSPFv2-OSPF Live-Live

Many new applications driving the growth of networking market are multicast based. Applications such as Internet Protocol television (IPTV) are typically associated with simultaneously delivering massive amount of sensitive data streams to large audiences. Packet drop is a critical issue in multimedia traffic. There is a demand to reduce multicast traffic loss to the range of milliseconds or to zero packet loss. The zero packet loss solution for multicast in case of single link failure is also known as live-live.

In a live-live network, multicast streams (typically two flows) form their own reverse path forwarding (RPF)/shortest path trees (SPT) over diversified physical links, so that failure on one link does not affect multicast traffic on other link. The existing multi topology technology in Cisco IOS software supports the multiple multicast topologies.

The OSPFv2-OSPF Live-Live feature enables the protocol independent multicast (PIM) to handle multiple multicast topologies. When a multicast topology is created and enabled on OSPF, IP prefixes on each topology are injected into topology-based Routing Information Base (RIB). PIM then decides which RIB to use for RPF lookup.

PIM RPF topology is a collection of routes used by PIM to perform the RPF operation when building shared or source trees. In a multi topology environment, multiple RPF topologies can be created in the same network. A particular source may be reachable in only one of the topologies or in several of them through different paths.

To select the RPF topology for a particular multicast distribution tree, consider the following:

1. Configure a policy that maps a group range to a topology. When RPF information needs to be resolved for the RP or the sources for a group within the range, the RPF lookup takes place in the specified topology. This can be used for PIM Sparse Mode (PIM-SM)/source-specific multicast (SSM)/Bidirectional(Bidir) PIM.

2. Configure a policy that maps a source prefix range to a topology. This can be used for PIM-SM and PIM-SSM.

3. Use the topology identified by the Join Attribute encoding in the received PIM packets.

The PIM Join Attribute extends PIM signaling to identify a topology that should be used when constructing a particular multicast distribution tree. For more details on the PIM Join Attribute, see PIM Multi-Topology ID (MT-ID) Join-Attribute IEEE draft.

How to Configure OSPFv2-OSPF Live-Live

- Configuring OSPFv2-OSPF Live-Live

Configuring OSPFv2-OSPF Live-Live

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip multicast-routing

4.    ip multicast rpf multitopology

5.    global-address-family ipv4 multicast

6.    topology {topology-A | topology-B}

7.    exit

8.    interface type number

9.    ip address address mask

10.    ip pim sparse-dense-mode

11.    ip ospf process-id area area-id

12.    topology ipv4 multicast topology-name

13.    exit

14.    router ospf process-id

15.    network ip-adddress mask area area-id

16.    address-family ipv4 multicast

17.    topology topology-name tid topology-id

18.    end

19.    configure terminal

20.    ip multicast topology multicast topology-name tid topology-id

21.    ip multicast rpf select topology multicast topology-name access-list number

22.    ip access-list extended access-list-number

23.    permit ip any ip-adddress

24.    end

25.    show ip multicast topology multicast topology-name

26.    debug ip multicast topology

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ip multicast-routing

Example:

Device(config)# ip multicast-routing

Enables IP multicast routing.

Step 4

ip multicast rpf multitopology

Example:

Device(config)# ip multicast rpf multitopology

Enables Multi Topology Routing (MTR) support for IP multicast routing.

Step 5

global-address-family ipv4 multicast

Example:

Device(config)# global-address-family ipv4 multicast

Enters global address family configuration mode and configures multi topology routing.

Step 6

topology {topology-A | topology-B}

Example:

Device(config-af)# topology live-A

Configures an OSPF process to route IP traffic under the specified topology instance.

Step 7

exit

Example:

Device(config-af)# exit

Exits address family configuration mode and returns to global configuration mode.

Step 8

interface type number

Example:

Device(config)# interface Gigabitethernet 1/0

Configures an interface type and enters interface configuration mode.

Step 9

ip address address mask

Example:

Device(config-if)# ip address 192.108.1.27 255.255.255.0

Sets a primary or secondary IP address for an interface.

Step 10

ip pim sparse-dense-mode

Example:

Device(config-if)# ip pim sparse-dense-mode

Enables PIM on an interface and treats the interface in either sparse mode or dense mode of operation, depending on which mode the multicast group operates in.

Step 11

ip ospf process-id area area-id

Example:

Device(config-if)# ip ospf 10 area 0

Enables OSPFv2 on an interface.

Step 12

topology ipv4 multicast topology-name

Example:

Device(config-if)# topology ipv4 multicast live-A

Configures a multi topology instance on an interface.

Step 13

exit

Example:

Device(config-if)# exit

Exits interface configuration mode and enters global configuration mode.

- Repeat Steps 9 to 12 to configure the next topology (topology ipv4 multicast live-B).

Step 14

router ospf process-id

Example:

Device(config)# router ospf 102

Enables OSPF routing and enters router configuration mode.

Step 15

network ip-adddress mask area area-id

Example:

Device(config-router)# network 192.168.129.16 0.0.0.3 area 20

Defines an interface on which OSPF runs and defines the area ID for that interface.

Step 16

address-family ipv4 multicast

Example:

Device(config-router)# address-family ipv4 multicast

Enters router address family configuration mode and configures OSPF to exchange IPv4 multicast prefixes.

Step 17

topology topology-name tid topology-id

Example:

Device(config-router-af)# topology live-A tid 100

Configures an OSPF process to route IP traffic under the specified topology instance.

- Repeat this step to configure the OSPF process to route IP traffic under another topology instance (topology live-B tid 200).

Step 18

end

Example:

Device(config-router-af)# end

Exits router address family configuration mode and returns to privileged EXEC mode.

Step 19

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 20

ip multicast topology multicast topology-name tid topology-id

Example:

Device(config)# ip multicast topology multicast live-A tid 100

Configures topology selection for the multicast streams.

- Repeat this step to configure another topology (ip multicast topology multicast live-B tid 200).

Step 21

ip multicast rpf select topology multicast topology-name access-list number

Example:

Device(config)# ip multicast rpf select topology multicast topology live-A 111

Associates a multicast topology with a multicast group with a specific route entry.

- Repeat this step to associate the topology with another multicast group (ip multicast rpf select topology multicast live-B 122).

Step 22

ip access-list extended access-list-number

Example:

Device(config)# ip access-list extended 111

Defines an IP access list to enable filtering for packets with IP helper-address destinations and enters extended named access list configuration mode.

Step 23

permit ip any ip-adddress

Example:

Device(config-ext-nacl)# permit ip any 203.0.113.1

Sets condition to allow a packet to pass a named IP access list.

- Repeat Steps 22 and 23 to define another IP access list and to set conditions to allow a packet to pass another named IP access list.

Step 24

end

Example:

Device(config-ext-nacl)# end

Exits extended named access list configuration mode and enters privileged EXEC mode.

Step 25

show ip multicast topology multicast topology-name

Example:

Device# show ip multicast topology multicast live-A

Displays topology information for multicast streams.

Step 26

debug ip multicast topology

Example:

Device# debug ip multicast topology

Enables debugging output for multicast stream topology.

Configuration Examples for OSPFv2-OSPF Live-Live

- Example: Configuring OSPFv2-OSPF Live-Live

Example: Configuring OSPFv2-OSPF Live-Live

ip multicast-routing
!
ip multicast rpf multitopology

!
global-address-family ipv4 multicast
topology live-A
topology live-B

int gigabitethernet 1/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-dense-mode
ip ospf 10 area 20
topology ipv4 multicast live-A
!
int gigabitethernet 2/0
ip address 192.0.2.2 255.255.255.0
ip pim sparse-dense-mode
ip ospf 11 area 21
topology ipv4 multicast live-B
!
router ospf 1
network 192.168.129.16 0.0.0.3 area 20
address-family ipv4 multicast
!!
topology live-A tid 10
topology live-B tid 20
!
!!
ip multicast topology multicast live-A tid 100
ip multicast topology multicast live-B tid 200
!
!!
ip multicast rpf select topology multicast live-A 111
ip multicast rpf select topology multicast live-B 122

!
ip access-list extended 111
permit ip any 203.0.113.254

ip access-list extended 122
permit ip any 203.0.113.251

Additional References for OSPFv2-OSPF Live-Live

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Configuring OSPF features

IP Routing: OSPF Configuration Guide

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv2-OSPF Live-Live

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv2-OSPF Live-Live

Feature Name

Releases

Feature Information

OSPFv2-OSPF Live-Live

15.4(2)T

The OSPFv2-OSPF Live-Live feature delivers multicast streams over non overlapping paths to various applications. The multicast traffic is split into multiple streams at the beginning of a protected network. All streams flow over non overlapping paths so that when a link failure occurs on one path, multicast traffic is still delivered through other paths. All streams are merged back at the end of the protected network.

No commands were introduced or modified.

Chapter 18. OSPFv3 Address Families

The Open Shortest Path First version 3 (OSPFv3) address families feature enables both IPv4 and IPv6 unicast traffic to be supported. With this feature, users may have two processes per interface, but only one process per address family (AF).

- Finding Feature Information

- Prerequisites for OSPFv3 Address Families

- Information About OSPFv3 Address Families

- How to Configure OSPFv3 Address Families

- Configuration Examples for OSPFv3 Address Families

- Additional References

- Feature Information for OSPFv3 Address Families

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv3 Address Families

- To use the IPv4 unicast address families (AF) in OSPFv3, you must enable IPv6 on a link, although the link may not be participating in IPv6 unicast AF.

- With the OSPFv3 Address Families feature, users may have two processes per interface, but only one process per AF. If the AF is IPv4, an IPv4 address must first be configured on the interface, but IPv6 must be enabled on the interface.

Information About OSPFv3 Address Families

- OSPFv3 Address Families

OSPFv3 Address Families

The OSPFv3 address families feature enables both IPv4 and IPv6 unicast traffic to be supported. With this feature, you may have two device processes per interface, but only one process per AF. If the IPv4 AF is used, an IPv4 address must first be configured on the interface, but IPv6 must be enabled on the interface. A single IPv4 or IPv6 OSPFv3 process running multiple instances on the same interface is not supported.

If you have an IPv6 network that uses OSPFv3 as its Interior Gateway Protocol (IGP) you may want to use the same IGP to help carry and install IPv4 routes. All devices on this network have an IPv6 forwarding stack. Some (or all) of the links on this network may be allowed to do IPv4 forwarding and be configured with IPv4 addresses. Pockets of IPv4-only devices exist around the edges running an IPv4 static or dynamic routing protocol. In this scenario, you need the ability to forward IPv4 traffic between these pockets without tunneling overhead, which means that any IPv4 transit device has both IPv4 and IPv6 forwarding stacks (that is, dual stack).

This feature allows a separate (possibly incongruent) topology to be constructed for the IPv4 AF. It installs IPv4 routes in the IPv4 Routing Information Base (RIB), and then the forwarding occurs natively. The OSPFv3 process fully supports an IPv4 AF topology and can redistribute routes from and into any other IPv4 routing protocol.

An OSPFv3 process can be configured to be either IPv4 or IPv6. The address-family command is used to determine which AF will run in the OSPFv3 process, and only one address family can be configured per instance. Once the AF is selected, you can enable multiple instances on a link and enable address-family-specific commands.

Different instance ID ranges are used for each AF. Each AF establishes different adjacencies, has a different link state database, and computes a different shortest path tree. The AF then installs the routes in the AF-specific RIB. LSAs that carry IPv6 unicast prefixes are used without any modification in different instances to carry each AF's prefixes.

The IPv4 subnets configured on OSPFv3-enabled interfaces are advertised through intra-area prefix LSAs, just as any IPv6 prefixes. External LSAs are used to advertise IPv4 routes redistributed from any IPv4 routing protocol, including connected and static. The IPv4 OSPFv3 process runs the Shortest Path First (SPF) calculations and finds the shortest path to those IPv4 destinations. These computed routes are then inserted in the IPv4 RIB (computed routes are inserted into an IPv6 RIB for an IPv6 AF).

Because the IPv4 OSPFv3 process allocates a unique pdbindex in the IPv4 RIB, all other IPv4 routing protocols can redistribute routes from it. The parse chain for all protocols is the same, so the ospfv3 keyword added to the list of IPv4 routing protocols causes OSPFv3 to appear in the redistribute command from any IPv4 routing protocol. With the ospfv3 keyword, IPv4 OSPFv3 routes can be redistributed into any other IPv4 routing protocol as defined in the redistribute ospfv3 command.

The OSPFv3 address families feature is supported as of Cisco IOS Release 15.1(3)S and Cisco IOS Release 15.2(1)T. Cisco devices that run software older than these releases and third-party devices will not neighbor with devices running the AF feature for the IPv4 AF because they do not set the AF bit. Therefore, those devices will not participate in the IPv4 AF SPF calculations and will not install the IPv4 OSPFv3 routes in the IPv6 RIB.

How to Configure OSPFv3 Address Families

- Configuring the OSPFv3 Device Process

- Configuring the IPv6 Address Family in OSPFv3

- Configuring the IPv4 Address Family in OSPFv3

- Configuring Route Redistribution in OSPFv3

- Enabling OSPFv3 on an Interface

- Defining an OSPFv3 Area Range for the IPv6 or IPv4 Address Family

Configuring the OSPFv3 Device Process

Once you have completed step 3 and entered OSPFv3 router configuration mode, you can perform any of the subsequent steps in this task as needed to configure OSPFv3 Device configuration.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    area area-ID [default-cost | nssa | stub]

5.    auto-cost reference-bandwidth Mbps

6.    default {area area-ID [range ipv6-prefix | virtual-link router-id]} [default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv6-prefix]

7.    ignore lsa mospf

8.    interface-id snmp-if-index

9.    log-adjacency-changes [detail]

10.    passive-interface [default | interface-type interface-number]

11.    queue-depth {hello | update} {queue-size | unlimited}

12.    router-id router-id

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enters router configuration mode for the IPv4 or IPv6 address family.

Step 4

area area-ID [default-cost | nssa | stub]

Example:

Device(config-router)# area 1

Configures the OSPFv3 area.

Step 5

auto-cost reference-bandwidth Mbps

Example:

Device(config-router)# auto-cost reference-bandwidth 1000

Controls the reference value OSPFv3 uses when calculating metrics for interfaces in an IPv4 OSPFv3 process.

Step 6

default {area area-ID [range ipv6-prefix | virtual-link router-id]} [default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv6-prefix]

Example:

Device(config-router)# default area 1

Returns an OSPFv3 parameter to its default value.

Step 7

ignore lsa mospf

Example:

Device(config-router)# ignore lsa mospf

Suppresses the sending of syslog messages when the device receives LSA Type 6 multicast OSPFv3 packets, which are unsupported.

Step 8

interface-id snmp-if-index

Example:

Device(config-router)# interface-id snmp-if-index

Configures OSPFv3 interfaces with Simple Network Management Protocol (SNMP) MIB-II interface Index (ifIndex) identification numbers in IPv4 and IPv6.

Step 9

log-adjacency-changes [detail]

Example:

Device(config-router)# log-adjacency-changes

Configures the device to send a syslog message when an OSPFv3 neighbor goes up or down.

Step 10

passive-interface [default | interface-type interface-number]

Example:

Device(config-router)# passive-interface default

Suppresses sending routing updates on an interface when an IPv4 OSPFv3 process is used.

Step 11

queue-depth {hello | update} {queue-size | unlimited}

Example:

Device(config-router)# queue-depth update 1500

Configures the number of incoming packets that the IPv4 OSPFv3 process can keep in its queue.

Step 12

router-id router-id

Example:

Device(config-router)# router-id 10.1.1.1

Enter this command to use a fixed router ID.

Configuring the IPv6 Address Family in OSPFv3

Perform this task to configure the IPv6 address family in OSPFv3. Once you have completed step 4 and entered IPv6 address-family configuration mode, you can perform any of the subsequent steps in this task as needed to configure the IPv6 AF.

This task can be performed in Cisco IOS Release 15.1(3)S and 15.2(1)T and later releases.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    address-family ipv6 unicast

5.    area area-ID range ipv6-prefix / prefix-length

6.    default {area area-ID [range ipv6-prefix | virtual-link router-id]} [default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv6-prefix]

7.    default-information originate [always ] metric metric-value | metric-type type-value | route-map map-name

8.    default-metric metric-value

9.    distance distance

10.    distribute-list prefix-list list-name {in [interface-type interface-number] | out routing-process [as-number]}

11.    maximum-paths number-paths

12.    summary-prefix prefix [not-advertise | tag tag-value]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv4 unicast

or

address-family ipv4 unicast
Enters IPv6 address family configuration mode for OSPFv3.

or

Enters IPv4 address family configuration mode for OSPFv3.

Step 5

area area-ID range ipv6-prefix / prefix-length

Example:

Device(config-router-af)# area 1 range 2001:DB8:0:0::0/128

Configures OSPFv3 area parameters.

Step 6

default {area area-ID [range ipv6-prefix | virtual-link router-id]} [default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv6-prefix]

Example:

Device(config-router-af)# default area 1

Returns an OSPFv3 parameter to its default value.

Step 7

default-information originate [always ] metric metric-value | metric-type type-value | route-map map-name

Example:

Device(config-router-af)# default-information originate always metric 100 metric-type 2

Generates a default external route into an OSPFv3 for a routing domain.

Step 8

default-metric metric-value

Example:

Device(config-router-af)# default-metric 10

Sets default metric values for IPv4 and IPv6 routes redistributed into the OSPFv3 routing protocol.

Step 9

distance distance

Example:

Device(config-router-af)# distance 200

Configures an administrative distance for OSPFv3 routes inserted into the routing table.

Step 10

distribute-list prefix-list list-name {in [interface-type interface-number] | out routing-process [as-number]}

Example:

Device(config-router-af)# distribute-list prefix-list PL1 in Ethernet0/0

Applies a prefix list to OSPFv3 routing updates that are received or sent on an interface.

Step 11

maximum-paths number-paths

Example:

Device(config-router-af)# maximum-paths 4

Controls the maximum number of equal-cost routes that a process for OSPFv3 routing can support.

Step 12

summary-prefix prefix [not-advertise | tag tag-value]

Example:

Device(config-router-af)# summary-prefix FEC0::/24

Configures an IPv6 summary prefix in OSPFv3.

Configuring the IPv4 Address Family in OSPFv3

Perform this task to configure the IPv4 address family in OSPFv3. Once you have completed step 4 and entered IPv4 address family configuration mode, you can perform any of the subsequent steps in this task as needed to configure the IPv4 AF.

Note

OSPFv3 IPv4 support is specified in RFC5838 and it does not support virtual links.

This task can be performed in Cisco IOS Release 15.1(3)S and 15.2(1)T and later releases.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    address-family ipv4 unicast

5.    area area-id range ip-address ip-address-mask [advertise | not-advertise] [cost cost]

6.    default {area area-ID[default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv4-prefix]

7.    default-information originate [always] metric metric-value | metric-type type-value | route-map map-name

8.    default-metric metric-value

9.    distance distance

10.    distribute-list prefix-list list-name {in [interface-type interface-number] | out routing-process [as-number]}

11.    maximum-paths number-paths

12.    summary-prefix prefix [not-advertise | tag tag-value]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

address-family ipv4 unicast

Example:

Device(config-router)# address-family ipv4 unicast

Enters IPv4 address family configuration mode for OSPFv3.

Step 5

area area-id range ip-address ip-address-mask [advertise | not-advertise] [cost cost]

Example:

Device(config-router-af)# area 0 range 192.168.110.0 255.255.0.0

Consolidates and summarizes routes at an area boundary.

Step 6

default {area area-ID[default-information originate [always | metric | metric-type | route-map] | distance | distribute-list prefix-list prefix-list-name {in | out} [interface] | maximum-paths paths | redistribute protocol | summary-prefix ipv4-prefix]

Example:

Device(config-router-af)# default area 1

Returns an OSPFv3 parameter to its default value.

Step 7

default-information originate [always] metric metric-value | metric-type type-value | route-map map-name

Example:

Device(config-router-af)# default-information originate always metric 100 metric-type 2

Generates a default external route into an OSPFv3 for a routing domain.

Step 8

default-metric metric-value

Example:

Device(config-router-af)# default-metric 10

Sets default metric values for IPv4 and IPv6 routes redistributed into the OSPFv3 routing protocol.

Step 9

distance distance

Example:

Device(config-router-af)# distance 200

Configures an administrative distance for OSPFv3 routes inserted into the routing table.

Step 10

distribute-list prefix-list list-name {in [interface-type interface-number] | out routing-process [as-number]}

Example:

Device(config-router-af)# distribute-list prefix-list PL1 in Ethernet 0/0

Applies a prefix list to OSPFv3 routing updates that are received or sent on an interface.

Step 11

maximum-paths number-paths

Example:

Device(config-router-af)# maximum-paths 4

Controls the maximum number of equal-cost routes that a process for OSPFv3 routing can support.

Step 12

summary-prefix prefix [not-advertise | tag tag-value]

Example:

Device(config-router-af)# summary-prefix FEC0::/24

Configures an IPv6 summary prefix in OSPFv3.

Configuring Route Redistribution in OSPFv3

This task can be performed in Cisco IOS Release 15.1(3)S and 15.2(1)T and later releases.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    address-family ipv6 unicast

5.    redistribute source-protocol [process-id] [options]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv4 unicast

Enters IPv6 address family configuration mode for OSPFv3.

or

Enters IPv4 address family configuration mode for OSPFv3.

Step 5

redistribute source-protocol [process-id] [options]

Example:

Redistributes IPv6 and IPv4 routes from one routing domain into another routing domain.

Enabling OSPFv3 on an Interface

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    Do one of the following:

- ospfv3 process-id area area-ID {ipv4 | ipv6} [instance instance-id]

- ipv6 ospf process-id area area-id [instance instance-id]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface ethernet 0/0

Specifies an interface type and number, and places the device in interface configuration mode.

Step 4

Do one of the following:

- ospfv3 process-id area area-ID {ipv4 | ipv6} [instance instance-id]

- ipv6 ospf process-id area area-id [instance instance-id]

Example:

Device(config-if)# ospfv3 1 area 1 ipv4

Example:

Device(config-if)# ipv6 ospf 1 area 0

Enables OSPFv3 on an interface with the IPv4 or IPv6 AF.

or

Enables OSPFv3 on an interface.

Defining an OSPFv3 Area Range for the IPv6 or IPv4 Address Family

The cost of the summarized routes will be the highest cost of the routes being summarized. For example, if the following routes are summarized:

OI  2001:DB8:0:7::/64 [110/20]
via FE80::A8BB:CCFF:FE00:6F00, Ethernet0/0
OI  2001:DB8:0:8::/64 [110/100]
via FE80::A8BB:CCFF:FE00:6F00, Ethernet0/0
OI  2001:DB8:0:9::/64 [110/20]
via FE80::A8BB:CCFF:FE00:6F00, Ethernet0/0

They become one summarized route, as follows:

OI  2001:DB8::/48 [110/100]
via FE80::A8BB:CCFF:FE00:6F00, Ethernet0/0

The task can be performed in Cisco IOS Release 15.1(3)S and 15.2(1)T and later releases.

Before You Begin

OSPFv3 routing must be enabled.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    address-family ipv6 unicast

5.    area area-ID range ipv6-prefix

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv4 unicast

Enters IPv6 address family configuration mode for OSPFv3.

or

Enters IPv4 address family configuration mode for OSPFv3.

Step 5

area area-ID range ipv6-prefix

Example:

Device(config-router-af)# area 1 range 2001:DB8:0:0::0/128

Configures OSPFv3 area parameters.

- Defining an OSPFv3 Area Range

Defining an OSPFv3 Area Range

The task can be performed in releases prior to Cisco IOS Release 15.1(3)S and 15.2(1)T.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 router ospf process-id

4.    area area-id range ipv6-prefix / prefix-length [ advertise | not-advertise] [cost cost]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

area area-id range ipv6-prefix / prefix-length [ advertise | not-advertise] [cost cost]

Example:

Device(config-router)# area 1 range 2001:DB8::/48

Consolidates and summarizes routes at an area boundary.

Configuration Examples for OSPFv3 Address Families

- Example: Configuring OSPFv3 Address Families

Example: Configuring OSPFv3 Address Families

Device# show ospfv3
Routing Process "ospfv3 1" with ID 10.0.0.1
Supports IPv6 Address Family
Event-log enabled, Maximum number of events: 1000, Mode: cyclic
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 0. Checksum Sum 0x000000
Number of areas in this router is 0. 0 normal 0 stub 0 nssa
Graceful restart helper support enabled
Reference bandwidth unit is 100 mbps
Relay willingness value is 128
Pushback timer value is 2000 msecs
Relay acknowledgement timer value is 1000 msecs
LSA cache Disabled : current count 0, maximum 1000
ACK cache Disabled : current count 0, maximum 1000
Selective Peering is not enabled
Hello requests and responses will be sent multicast

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

OSPFv3 Address Families

“ OSPF Forwarding Address Suppression in Translated Type-5 LSAs ” module

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 Address Families

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 Address Families

Feature Name

Releases

Feature Information

OSPFv3 Address Families

15.1(3)S

15.1(1)SY

15.2(1)T

The OSPFv3 address families feature enables IPv4 and IPv6 unicast traffic to be supported with a single network topology.

The following commands were introduced or modified: address-family ipv4 (OSPFv3), address-family ipv6 (OSPFv3), area (OSPFv3), auto-cost (OSPFv3), bfd all-interfaces (OSPFv3), clear ospfv3 counters, clear ospfv3 force-spf, clear ospfv3 process, clear ospfv3 redistribution, clear ospfv3 traffic, debug ospfv3, debug ospfv3 database-timer rate-limit, debug ospfv3 events, debug ospfv3 lsdb, debug ospfv3 packet, debug ospfv3 spf statistic, default (OSPFv3), default-information originate (OSPFv3), default-metric (OSPFv3), distance (OSPFv3), distribute-list prefix-list (OSPFv3), event-log (OSPFv3), log-adjacency-changes (OSPFv3), maximum-paths (OSPFv3), ospfv3 area, ospfv3 authentication, ospfv3 bfd, ospfv3 cost, ospfv3 database-filter, ospfv3 dead-interval, ospfv3 demand-circuit, ospfv3 encryption, ospfv3 flood-reduction, ospfv3 hello-interval, ospfv3 mtu-ignore, ospfv3 network, ospfv3 priority, ospfv3 retransmit-interval, ospfv3 transmit-delay, passive-interface (OSPFv3), queue-depth (OSPFv3), redistribute (OSPFv3), router ospfv3, router-id (OSPFv3), show ospfv3 border-routers, show ospfv3 database, show ospfv3 events, show ospfv3 flood-list, show ospfv3 graceful-restart, show ospfv3 interface, show ospfv3 max-metric, show ospfv3 neighbor, show ospfv3 request-list, show ospfv3 retransmission-list, show ospfv3 statistics, show ospfv3 summary-prefix, show ospfv3 timers rate-limit, show ospfv3 traffic, show ospfv3 virtual-links, summary-prefix (OSPFv3), timers pacing flood (OSPFv3), timers pacing lsa-group (OSPFv3), timers pacing retransmission (OSPFv3).

Chapter 19. OSPF Forwarding Address Suppression in Translated Type-5 LSAs

The OSPF Forwarding Address Suppression in Translated Type-5 LSAs feature causes a not-so-stubby area (NSSA) area border router (ABR) to translate Type-7 link state advertisements (LSAs) to Type-5 LSAs, but use the address 0.0.0.0 for the forwarding address instead of that specified in the Type-7 LSA. This feature causes routers that are configured not to advertise forwarding addresses into the backbone to direct forwarded traffic to the translating NSSA ABRs.

- Finding Feature Information

- Prerequisites for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

- Information About OSPF Forwarding Address Suppression in Translated Type-5 LSAs

- How to Suppress OSPF Forwarding Address in Translated Type-5 LSAs

- Configuration Examples for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

- Additional References

- Feature Information for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

This document presumes you have OSPF configured on the networking device; it does not document other steps to configure OSPF.

Information About OSPF Forwarding Address Suppression in Translated Type-5 LSAs

- Benefits of OSPF Forwarding Address Suppression in Translated Type-5 LSAs

- When to Suppress OSPF Forwarding Address in Translated Type-5 LSAs

Benefits of OSPF Forwarding Address Suppression in Translated Type-5 LSAs

The OSPF Forwarding Address Suppression in Translated Type-5 LSAs feature causes an NSSA ABR to translate Type-7 LSAs to Type-5 LSAs, but use the 0.0.0.0 as the forwarding address instead of that specified in the Type-7 LSA. This feature causes routers that are configured not to advertise forwarding addresses into the backbone to direct forwarded traffic to the translating NSSA ASBRs.

When to Suppress OSPF Forwarding Address in Translated Type-5 LSAs

In the figure below, it would be advantageous to filter Area 2 addresses from Area 0 to minimize the number of routes introduced into the backbone (Area 0). However, using the area rangecommand to consolidate and summarize routes at the area boundary--filtering the Area 2 addresses--will not work because the Area 2 addresses include forwarding addresses for Type-7 LSAs that are generated by the ASBR. If these Type-7 LSA forwarding addresses have been filtered out of Area 0, the backbone routers cannot reach the prefixes advertised in the translated Type-5 LSAs (autonomous system external LSAs).

OSPF Forwarding Address Suppression in Translated Type-5 LSAs

This problem is solved by suppressing the forwarding address on the ABR so that the forwarding address is set to 0.0.0.0 in the Type-5 LSAs that were translated from Type-7 LSAs. A forwarding address set to 0.0.0.0 indicates that packets for the external destination should be forwarded to the advertising OSPF router, in this case, the translating NSSA ABR.

Before configuring this feature, consider the following caution.

Caution

Configuring this feature causes the router to be noncompliant with RFC 1587. Also, suboptimal routing might result because there might be better paths to reach the destination’s forwarding address. This feature should not be configured without careful consideration and not until the network topology is understood.

How to Suppress OSPF Forwarding Address in Translated Type-5 LSAs

- Suppressing OSPF Forwarding Address in Translated Type-5 LSAs

Suppressing OSPF Forwarding Address in Translated Type-5 LSAs

Caution

Configuring this feature causes the router to be noncompliant with RFC 1587. Also, suboptimal routing might result because there might be better paths to reach the destination’s forwarding address. This feature should not be configured without careful consideration and not until the network topology is understood.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    area area-id nssa translate type7 suppress-fa

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables higher privilege levels, such as privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Device(config)# router ospf 1

Enables OSPF routing and enters device configuration mode.

- The process-id argument identifies the OSPF process.

Step 4

area area-id nssa translate type7 suppress-fa

Example:

Device(config-router)# area 10 nssa translate type7 suppress-fa

Configures an area as a not-so-stubby-area (NSSA) and suppresses the forwarding address in translated Type-7 LSAs.

Step 5

end

Example:

Device(config-router)# end

Exits configuration mode and returns to privileged EXEC mode.

Configuration Examples for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

- Example Suppressing OSPF Forwarding Address in Translated Type-5 LSAs

Example Suppressing OSPF Forwarding Address in Translated Type-5 LSAs

This example suppresses the forwarding address in translated Type-5 LSAs:

interface ethernet 0
ip address 10.93.1.1 255.255.255.0
ip ospf cost 1
!
interface ethernet 1
ip address 10.94.1.1 255.255.255.0
!
router ospf 1
network 10.93.0.0 0.0.255.255 area 0.0.0.0
network 10.94.0.0 0.0.255.255 area 10
area 10 nssa translate type7 suppress-fa

Additional References

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

OSPFv3 Address Families

“ OSPFv3 Address Families” module

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIBs

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

Configuring the OSPF Forwarding Address Suppression in Translated Type-5 LSAs feature causes the router to be noncompliant with RFC 1587.

The OSPF NSSA Option

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Forwarding Address Suppression in Translated Type-5 LSAs

Feature Name

Releases

Feature Information

OSPF Forwarding Address Suppression in Translated Type-5 LSAs

The OSPF Forwarding Address Suppression in Translated Type-5 LSAs feature causes a not-so-stubby area (NSSA) area border router (ABR) to translate Type-7 link state advertisements (LSAs) to Type-5 LSAs, but to use the address 0.0.0.0 for the forwarding address instead of that specified in the Type-7 LSA. This feature causes routers that are configured not to advertise forwarding addresses into the backbone to direct forwarded traffic to the translating NSSA ABRs.

The following commands are introduced or modified:

- area nssa translate

- show ip ospf

OSPF Forwarding Address Suppression in Translated Type-5 LSAs

12.2(15)T

The OSPF Forwarding Address Suppression in Translated Type-5 LSAs feature causes a not-so-stubby area (NSSA) area border router (ABR) to translate Type-7 link state advertisements (LSAs) to Type-5 LSAs, but to use the address 0.0.0.0 for the forwarding address instead of that specified in the Type-7 LSA. This feature causes routers that are configured not to advertise forwarding addresses into the backbone to direct forwarded traffic to the translating NSSA ABRs.

The following commands are introduced or modified:

- area nssa translate

- show ip ospf

Chapter 20. OSPF Inbound Filtering Using Route Maps with a Distribute List

The OSPF Inbound Filtering Using Route Maps with a Distribute List feature allows users to define a route map to prevent Open Shortest Path First (OSPF) routes from being added to the routing table. In the route map, the user can match on any attribute of the OSPF route.

- Finding Feature Information

- Prerequisites for OSPF Inbound Filtering Using Route Maps with a Distribute List

- Information About OSPF Inbound Filtering Using Route Maps with a Distribute List

- How to Configure OSPF Inbound Filtering Using Route Maps

- Configuration Examples for OSPF Inbound Filtering Using Route Maps with a Distribute List

- Additional References

- Feature Information for OSPF Inbound Filtering Using Route Maps with a Distribute List

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Inbound Filtering Using Route Maps with a Distribute List

It is presumed that you have OSPF configured in your network.

Information About OSPF Inbound Filtering Using Route Maps with a Distribute List

Users can define a route map to prevent OSPF routes from being added to the routing table. This filtering happens at the moment when OSPF is installing the route in the routing table. This feature has no effect on link-state advertisement (LSA) flooding. In the route map, the user can match on any attribute of the OSPF route. That is, the route map could be based on the following match options:

- match interface

- match ip address

- match ip next-hop

- match ip route-source

- match metric

- match route-type

- match tag

This feature can be useful during redistribution if the user tags prefixes when they get redistributed on Autonomous System Boundary Routers (ASBRs) and later uses the tag to filter the prefixes from being installed in the routing table on other routers.

Filtering Based on Route Tag

Users can assign tags to external routes when they are redistributed to OSPF. Then the user can deny or permit those routes in the OSPF domain by identifying that tag in the route-map and distribute-list in commands.

Filtering Based on Route Type

In OSPF, the external routes could be Type 1 or Type 2. Users can create route maps to match either Type 1 or Type 2 and then use the distribute-list in command to filter certain prefixes. Also, route maps can identify internal routes (interarea and intra-area) and then those routes can be filtered.

Filtering Based on Route Source

When a match is done on the route source, the route source represents the OSPF Router ID of the LSA originator of the LSA in which the prefix is advertised.

Filtering Based on Interface

When a match is done on the interface, the interface represents the outgoing interface for the route that OSPF is trying to install in the routing table.

Filtering Based on Next Hop

When a match is done on the next hop, the next hop represents the next hop for the route that OSPF is trying to install in the routing table.

Note

The distribute-list in command can be configured to prevent routes from being installed in the global Routing Information Base (RIB). Prior to the implementation of OSPF local RIB (for feature information on OSPF local RIB, see OSPFv2 Local RIB), OSPF would attempt to install a less preferred route (e.g. an inter-area route when the intra-area path is filtered). With OSPF local RIB, only the best route is considered (because this is the only route the local RIB maintains). There is no concept of a "second-best" OSPF route. For more information on the routing algorithm used by Cisco OSPF routers, please refer to RFC 2328.

How to Configure OSPF Inbound Filtering Using Route Maps

- Configuring OSPF Route Map-Based Filtering

Configuring OSPF Route Map-Based Filtering

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    route-map map-tag [permit | deny] [sequence-number]

4.    match tag tag-name

5.    Repeat Steps 3 and 4 with other route-map and match commands.

6.    exit

7.    router ospf process-id

8.    distribute-list route-map map-tag in

9.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

route-map map-tag [permit | deny] [sequence-number]

Example:

Router(config)# route-map tag-filter deny 10

Defines a route map to control filtering.

Step 4

match tag tag-name

Example:

Router(config-router)# match tag 777

Matches routes with a specified name, to be used as the route map is referenced.

- At least one match command is required, but it need not be this matchcommand. This is just an example.

- The list of match commands available to be used in this type of route map appears on the distribute-list in command reference page.

- This type of route map will have no set commands.

Step 5

Repeat Steps 3 and 4 with other route-map and match commands.

Optional.

Step 6

exit

Example:

Router(config-router)# exit

Exits router configuration mode.

Step 7

router ospf process-id

Example:

Router(config)# router ospf 1

Configures an OSPF routing process.

Step 8

distribute-list route-map map-tag in

Example:

Router(config-router)# distribute-list route-map tag-filter in

Enables filtering based on an OSPF route map.

Step 9

end

Example:

Router(config-router)# end

Exits router configuration mode.

Configuration Examples for OSPF Inbound Filtering Using Route Maps with a Distribute List

- Example OSPF Route Map-Based Filtering

Example OSPF Route Map-Based Filtering

In this example, OSPF external LSAs have a tag. The value of the tag is examined before the prefix is installed in the routing table. All OSPF external prefixes that have the tag value of 777 are filtered (prevented from being installed in the routing table). The permit statement with sequence number 20 has no match conditions, and there are no other route-map statements after sequence number 20, so all other conditions are permitted.

route-map tag-filter deny 10
match tag 777
route-map tag-filter permit 20
!
router ospf 1
router-id 10.0.0.2
log-adjacency-changes
network 172.16.2.1 0.0.0.255 area 0
distribute-list route-map tag-filter in

Additional References

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Inbound Filtering Using Route Maps with a Distribute List

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Inbound Filtering Using Route Maps with a Distribute List

Feature Name

Releases

Feature Information

OSPF Inbound Filterng Using Route Maps with a Distribute List

12.0(24)S 12.2(15)T 12.2(18)S 12.2(27)SBC Cisco IOS XE 3.1.0 SG

The OSPF Inbound Filtering Using Route Maps with a Distribute List feature allows users to define a route map to prevent Open Shortest Path First (OSPF) routes from being added to the routing table. In the route map, the user can match on any attribute of the OSPF route..

The following command was introduced or modified: distribute-list in (IP).

Chapter 21. OSPFv3 Fast Convergence: LSA and SPF Throttling

The Open Shortest Path First version 3 (OSPFv3) link-state advertisement (LSAs) and shortest-path first (SPF) throttling feature provides a dynamic mechanism to slow down link-state advertisement updates in OSPFv3 during times of network instability. It also allows faster OSPFv3 convergence by providing LSA rate limiting in milliseconds.

- Finding Feature Information

- Information About OSPFv3 Fast Convergence: LSA and SPF Throttling

- How to Configure OSPFv3 Fast Convergence: LSA and SPF Throttling

- Configuration Examples for OSPFv3 Fast Convergence: LSA and SPF Throttling

- Additional References

- Feature Information for OSPFv3 Fast Convergence: LSA and SPF Throttling

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPFv3 Fast Convergence: LSA and SPF Throttling

- Fast Convergence: LSA and SPF Throttling

Fast Convergence: LSA and SPF Throttling

The OSPFv3 LSA and SPF throttling feature provides a dynamic mechanism to slow down link-state advertisement updates in OSPFv3 during times of network instability. It also allows faster OSPFv3 convergence by providing LSA rate limiting in milliseconds.

OSPFv3 can use static timers for rate-limiting SPF calculation and LSA generation. Although these timers are configurable, the values used are specified in seconds, which poses a limitation on OSPFv3 convergence. LSA and SPF throttling achieves subsecond convergence by providing a more sophisticated SPF and LSA rate-limiting mechanism that is able to react quickly to changes and also provide stability and protection during prolonged periods of instability.

How to Configure OSPFv3 Fast Convergence: LSA and SPF Throttling

- Tuning LSA and SPF Timers for OSPFv3 Fast Convergence

- Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

Tuning LSA and SPF Timers for OSPFv3 Fast Convergence

This task can be performed in Cisco IOS Release 15.1(3)S and 15.2(1)T and later releases.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    timers lsa arrival milliseconds

5.    timers pacing flood milliseconds

6.    timers pacing lsa-group seconds

7.    timers pacing retransmission milliseconds

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

timers lsa arrival milliseconds

Example:

Device(config-rtr)# timers lsa arrival 300

Sets the minimum interval at which the software accepts the same LSA from OSPFv3 neighbors.

Step 5

timers pacing flood milliseconds

Example:

Device(config-rtr)# timers pacing flood 30

Configures LSA flood packet pacing.

Step 6

timers pacing lsa-group seconds

Example:

Device(config-router)# timers pacing lsa-group 300

Changes the interval at which OSPFv3 LSAs are collected into a group and refreshed, checksummed, or aged.

Step 7

timers pacing retransmission milliseconds

Example:

Device(config-router)# timers pacing retransmission 100

Configures LSA retransmission packet pacing in IPv4 OSPFv3.

Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

This task can be performed in releases prior to Cisco IOS Release 15.1(3)S and 15.2(1)T.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 router ospf process-id

4.    timers throttle spf spf-start spf-hold spf-max-wait

5.    timers throttle lsa start-interval hold-interval max-interval

6.    timers lsa arrival milliseconds

7.    timers pacing flood milliseconds

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

timers throttle spf spf-start spf-hold spf-max-wait

Example:

Device(config-rtr)# timers throttle spf 200 200 200

Turns on SPF throttling.

Step 5

timers throttle lsa start-interval hold-interval max-interval

Example:

Device(config-rtr)# timers throttle lsa 300 300 300

Sets rate-limiting values for OSPFv3 LSA generation.

Step 6

timers lsa arrival milliseconds

Example:

Device(config-rtr)# timers lsa arrival 300

Sets the minimum interval at which the software accepts the same LSA from OSPFv3 neighbors.

Step 7

timers pacing flood milliseconds

Example:

Device(config-rtr)# timers pacing flood 30

Configures LSA flood packet pacing.

Configuration Examples for OSPFv3 Fast Convergence: LSA and SPF Throttling

- Example: Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

Example: Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

The following example show how to display the configuration values for SPF and LSA throttling timers:

Device# show ipv6 ospf

Routing Process "ospfv3 1" with ID 10.9.4.1
Event-log enabled, Maximum number of events: 1000, Mode: cyclic
It is an autonomous system boundary router
Redistributing External Routes from,
ospf 2
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

OSPFv3 Fast Convergence: LSA and SPF Throttling

“ OSPF Shortest Path First Throttling ” module

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 Fast Convergence: LSA and SPF Throttling

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 Fast Convergence: LSA and SPF Throttling

Feature Name

Releases

Feature Information

OSPFv3 Fast Convergence: LSA and SPF Throttling

12.2(33)SRC

15.0(1)SY

15.0(1)M

15.1(1)SY

The OSPFv3 LSA and SPF throttling feature provides a dynamic mechanism to slow down link-state advertisement updates in OSPFv3 during times of network instability.

The following commands were introduced or modified: ipv6 router ospf, router ospfv3, timers lsa arrival, timers pacing flood, timers pacing lsa-group, timers pacing retransmission, timers throttle lsa, timers throttle spf.

Chapter 22. OSPF Shortest Path First Throttling

The OSPF Shortest Path First Throttling feature makes it possible to configure SPF scheduling in millisecond intervals and to potentially delay shortest path first (SPF) calculations during network instability. SPF is scheduled to calculate the Shortest Path Tree (SPT) when there is a change in topology. One SPF run may include multiple topology change events.

The interval at which the SPF calculations occur is chosen dynamically and is based on the frequency of topology changes in the network. The chosen interval is within the boundary of the user-specified value ranges. If network topology is unstable, SPF throttling calculates SPF scheduling intervals to be longer until topology becomes stable.

Feature Specifications for OSPF Shortest Path First Throttling

Feature History

Release

Modification

12.2(14)S

This feature was introduced.

12.0(23)S

This feature was integrated into Cisco Release 12.0(23)S.

12.2(15)T

This feature was integrated into Cisco IOS Release 12.2(15)T.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at Click Here . You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

- Finding Feature Information

- Information About OSPF SPF Throttling

- How to Configure OSPF SPF Throttling

- Configuration Examples for OSPF SPF Throttling

- Additional References

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPF SPF Throttling

- Shortest Path First Calculations

Shortest Path First Calculations

SPF calculations occur at the interval set by the timers throttle spfcommand. The wait interval indicates the amount of time to wait until the next SPF calculation occurs. Each wait interval after that calculation is twice as long as the previous one until the wait interval reaches the maximum wait time specified.

The SPF timing can be better explained using an example. In this example the start interval is set at 5 milliseconds (ms), the wait interval at 1000 milliseconds, and the maximum wait time is set at 90,000 milliseconds.

timers throttle spf 5 1000 90000

The figure below shows the intervals at which the SPF calculations occur so long as at least one topology change event is received in a given wait interval.

SPF Calculation Intervals Set by the timers throttle spf Command

Notice that the wait interval between SPF calculations doubles when at least one topology change event is received during the previous wait interval. Once the maximum wait time is reached, the wait interval remains the same until the topology stabilizes and no event is received in that interval.

If the first topology change event is received after the current wait interval, the SPF calculation is delayed by the amount of time specified as the start interval. The subsequent wait intervals continue to follow the dynamic pattern.

If the first topology change event occurs after the maximum wait interval begins, the SPF calculation is again scheduled at the start interval and subsequent wait intervals are reset according the parameters specified in the timers throttle spfcommand. Notice in the figure below that a topology change event was received after the start of the maximum wait time interval and that the SPF intervals have been reset.

Timer Intervals Reset after Topology Change Event

How to Configure OSPF SPF Throttling

- Configuring OSPF SPF Throttling

- Verifying SPF Throttle Values

Configuring OSPF SPF Throttling

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type slot / port

4.    ip address ip-address mask [secondary]

5.    exit

6.    router ospf process-id

7.    network network-number [mask | prefix-length]

8.    timers throttle spf spf-start spf-hold spf-max-wait

9.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables higher privilege levels, such as privileged EXEC mode.

Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface type slot / port

Example:

Router(config)# interface ethernet 1/1/1

Enters interface configuration mode for the interface specified.

Step 4

ip address ip-address mask [secondary]

Example:

Router(config-if)# ip address 192.168.0.2 255.255.255.0

Sets a primary or secondary IP address for an interface.

Step 5

exit

Example:

router# exit

Exits interface configuration mode.

Step 6

router ospf process-id

Example:

Router(config)# router ospf 1

Configures an OSPF routing process.

Step 7

network network-number [mask | prefix-length]

Example:

Router(config-router)# network 192.168.0.0 0.0.255.255 area 0

Configures the subnet number and mask for a Dynamic Host Configuration Protocol (DHCP) address pool on a Cisco IOS DHCP Server.

Step 8

timers throttle spf spf-start spf-hold spf-max-wait

Example:

Router(config-router)# timers throttle spf 10 4800 90000

Sets OSPF throttling timers.

Step 9

end

Example:

Router(config-router)# end

Exits configuration mode.

Verifying SPF Throttle Values

To verify SPF throttle timer values, use the show ip ospf command. The values are displayed in the lines that begin, "Initial SPF schedule delay...," "Minimum hold time between two consecutive SPFs...," and "Maximum wait time between two consecutive SPFs...."

Router# show ip ospf
Routing Process "ospf 1" with ID 10.10.10.2 and Domain ID 0.0.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
It is an autonomous system boundary router
Redistributing External Routes from,
static, includes subnets in redistribution
Initial SPF schedule delay 5 msecs
Minimum hold time between two consecutive SPFs 1000 msecs
Maximum wait time between two consecutive SPFs 90000 msecs
Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 4. Checksum Sum 0x17445
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 2
Area has no authentication
SPF algorithm last executed 19:11:15.140 ago
SPF algorithm executed 28 times
Area ranges are
Number of LSA 4. Checksum Sum 0x2C1D4
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0

The table below describes the show ip ospf display fields and their descriptions.

show ip ospf Field Descriptions

Field

Description

Routing process "ospf 201" with ID 192.42.110.200

Process ID and OSPF router ID.

Supports ...

Number of types of service supported (Type 0 only).

It is ...

Possible types are internal, area border, or autonomous system boundary.

Summary Link update interval

Specifies summary update interval in hours:minutes:seconds, and time until next update.

External Link update interval

Specifies external update interval in hours:minutes:seconds, and time until next update.

Redistributing External Routes from

Lists of redistributed routes, by protocol.

SPF calculations

Lists start, hold, and maximum wait interval values in milliseconds.

Number of areas

Number of areas in router, area addresses, and so on.

SPF algorithm last executed

Shows the last time an SPF calculation was performed in response to topology change event records.

Link State Update Interval

Specifies router and network link-state update interval in hours:minutes:seconds, and time until next update.

Link State Age Interval

Specifies max-aged update deletion interval, and time until next database cleanup, in hours:minutes:seconds.

Configuration Examples for OSPF SPF Throttling

- Throttle Timers Example

Throttle Timers Example

This example shows a router configured with the start, hold, and maximum interval values for the timers throttle spf command set at 5, 1,000, and 90,000 milliseconds, respectively.

router ospf 1
router-id 10.10.10.2
log-adjacency-changes
timers throttle spf 5 1000 90000
redistribute static subnets
network 21.21.21.0 0.0.0.255 area 0
network 22.22.22.0 0.0.0.255 area 00

Additional References

For additional information related to OSPF, refer to the following references:

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

OSPF configuration tasks

"Configuring OSPF" module in the Cisco IOS IP Routing Protocols Configuration Guide

OSPFv3 Fast Convergence: LSA and SPF Throttling

‘OSPFv3 Fast Convergence: LSA and SPF Throttling” module

Standards

Standards

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

MIBs

MIBs

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Chapter 23. OSPF Support for Fast Hello Packets

The OSPF Support for Fast Hello Packets feature provides a way to configure the sending of hello packets in intervals less than 1 second. Such a configuration would result in faster convergence in an Open Shortest Path First (OSPF) network.

- Finding Feature Information

- Prerequisites for OSPF Support for Fast Hello Packets

- Information About OSPF Support for Fast Hello Packets

- How to Configure OSPF Fast Hello Packets

- Configuration Examples for OSPF Support for Fast Hello Packets

- Additional References

- Feature Information for OSPF Support for Fast Hello Packets

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Support for Fast Hello Packets

OSPF must be configured in the network already or configured at the same time as the OSPF Support for Fast Hello Packets feature.

Information About OSPF Support for Fast Hello Packets

- OSPF Hello Interval and Dead Interval

- OSPF Fast Hello Packets

- Benefits of OSPF Fast Hello Packets

OSPF Hello Interval and Dead Interval

OSPF hello packets are packets that an OSPF process sends to its OSPF neighbors to maintain connectivity with those neighbors. The hello packets are sent at a configurable interval (in seconds). The defaults are 10 seconds for an Ethernet link and 30 seconds for a non broadcast link. Hello packets include a list of all neighbors for which a hello packet has been received within the dead interval. The dead interval is also a configurable interval (in seconds), and defaults to four times the value of the hello interval. The value of all hello intervals must be the same within a network. Likewise, the value of all dead intervals must be the same within a network.

These two intervals work together to maintain connectivity by indicating that the link is operational. If a router does not receive a hello packet from a neighbor within the dead interval, it will declare that neighbor to be down.

OSPF Fast Hello Packets

OSPF fast hello packets refer to hello packets being sent at intervals of less than 1 second. To understand fast hello packets, you should already understand the relationship between OSPF hello packets and the dead interval. See the section OSPF Hello Interval and Dead Interval.

OSPF fast hello packets are achieved by using the ip ospf dead-interval command. The dead interval is set to 1 second, and the hello-multiplier value is set to the number of hello packets you want sent during that 1 second, thus providing subsecond or "fast" hello packets.

When fast hello packets are configured on the interface, the hello interval advertised in the hello packets that are sent out this interface is set to 0. The hello interval in the hello packets received over this interface is ignored.

The dead interval must be consistent on a segment, whether it is set to 1 second (for fast hello packets) or set to any other value. The hello multiplier need not be the same for the entire segment as long as at least one hello packet is sent within the dead interval.

Benefits of OSPF Fast Hello Packets

The benefit of the OSPF Fast Hello Packets feature is that your OSPF network will experience faster convergence time than it would without fast hello packets. This feature allows you to detect lost neighbors within 1 second. It is especially useful in LAN segments, where neighbor loss might not be detected by the Open System Interconnection (OSI) physical layer and data-link layer.

How to Configure OSPF Fast Hello Packets

- Configuring OSPF Fast Hello Packets

Configuring OSPF Fast Hello Packets

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ip ospf dead-interval minimal hello-multiplier multiplier

5.    end

6.    show ip ospf interface [interface-type interface-number]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables higher privilege levels, such as privileged EXEC mode.

Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Router(config)# interface ethernet 0

Configures an interface type and enters interface configuration mode.

Step 4

ip ospf dead-interval minimal hello-multiplier multiplier

Example:

Router(config-if)# ip ospf dead-interval minimal hello-multiplier 5

Sets the interval during which at least one hello packet must be received, or else the neighbor is considered down.

- In the example, OSPF Support for Fast Hello Packets is enabled by specifying the minimal keyword and the hello-multiplier keyword and value. Because the multiplier is set to 5, five hello packets will be sent every second.

Step 5

end

Example:

Router(config-if)# end

(Optional) Saves configuration commands to the running configuration file, exits configuration mode, and returns to privileged EXEC mode.

- Use this command when you are ready to exit configuration mode and save the configuration to the running configuration file.

Step 6

show ip ospf interface [interface-type interface-number]

Example:

Router# show ip ospf interface ethernet 1/3

(Optional) Displays OSPF-related interface information.

- The relevant fields that verify OSPF fast hello packets are indicated in the sample output following this table.

Examples

The following example output verifies that OSPF Support for Fast Hello Packets is configured. In the line that begins with "Timer intervals configured," the hello interval is 200 milliseconds, the dead interval is 1 second, and the next hello packet is due in 76 milliseconds.

Router# show ip ospf interface ethernet 1/3
Ethernet1/3 is up, line protocol is up
Internet Address 172.16.1.2/24, Area 0
Process ID 1, Router ID 172.17.0.2, Network Type BROADCAST, Cost:1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.17.0.2, Interface address 172.16.1.2
Backup Designated router (ID) 172.16.0.1, Interface address 172.16.1.1
Timer intervals configured, Hello 200 msec, Dead 1, Wait 1, Retransmit 5
Hello due in 76 msec
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 2, maximum is 3
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 172.16.0.1  (Backup Designated Router)
Suppress hello for 0 neighbor(s)

Configuration Examples for OSPF Support for Fast Hello Packets

- Example OSPF Fast Hello Packets

Example OSPF Fast Hello Packets

The following example configures OSPF fast hello packets; the dead interval is 1 second and five hello packets are sent every second:

interface ethernet 1
ip ospf dead-interval minimal hello-multiplier 5

Additional References

The following sections provide references related to OSPF Support for Fast Hello Packets.

Related Documents

Related Topic

Document Title

OSPF commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS IP Routing: OSPF Command Reference

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

None

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Support for Fast Hello Packets

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Support for Fast Hello Packets

Feature Name

Releases

Feature Information

OSPF Support for Fast Hello Packets

12.0(23)S 12.2(18)S 12.2(27)SBC 12.2(15)T

The OSPF Support for Fast Hello Packets feature provides a way to configure the sending of hello packets in intervals less than 1 second. Such a configuration would result in faster convergence in an Open Shortest Path First (OSPF) network.

The following command was introduced: ip ospf dead-interval.

Chapter 24. OSPF Incremental SPF

The Open Shortest Path First (OSPF) protocol can be configured to use an incremental SPF algorithm for calculating the shortest path first routes. Incremental SPF is more efficient than the full SPF algorithm, thereby allowing OSPF to converge faster on a new routing topology in reaction to a network event.

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information for OSPF Incremental SPF.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

- Finding Feature Information

- Prerequisites for OSPF Incremental SPF

- Information About OSPF Incremental SPF

- How to Enable OSPF Incremental SPF

- Configuration Examples for OSPF Incremental SPF

- Additional References

- Feature Information for OSPF Incremental SPF

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Incremental SPF

It is presumed that you have OSPF configured in your network.

Information About OSPF Incremental SPF

OSPF uses Dijkstra’s SPF algorithm to compute the shortest path tree (SPT). During the computation of the SPT, the shortest path to each node is discovered. The topology tree is used to populate the routing table with routes to IP networks. When changes to a Type-1 or Type-2 link-state advertisement (LSA) occur in an area, the entire SPT is recomputed. In many cases, the entire SPT need not be recomputed because most of the tree remains unchanged. Incremental SPF allows the system to recompute only the affected part of the tree. Recomputing only a portion of the tree rather than the entire tree results in faster OSPF convergence and saves CPU resources. Note that if the change to a Type-1 or Type-2 LSA occurs in the calculating router itself, then the full SPT is performed.

Incremental SPF is scheduled in the same way as the full SPF. Routers enabled with incremental SPF and routers not enabled with incremental SPF can function in the same internetwork.

How to Enable OSPF Incremental SPF

- Enabling Incremental SPF

Enabling Incremental SPF

This section describes how to enable incremental SPF.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    ispf

5.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Router(config)# router ospf 1

Configures an OSPF routing process.

Step 4

ispf

Example:

Router(config-router)# ispf

Enables incremental SPF.

Step 5

end

Example:

Router(config-router)# end

Exits router configuration mode.

Configuration Examples for OSPF Incremental SPF

- Example Incremental SPF

Example Incremental SPF

This example enables incremental SPF:

router ospf 1
ispf

Additional References

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Incremental SPF

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Incremental SPF

Feature Name

Releases

Feature Information

OSPF Incremental SPF

12.0(24)S 12.3(2)T 12.2(18)S 12.2(27)SBC 12.2(33)SRA 12.2(33)XNE Cisco IOS XE 3.1.0 SG

OSPF can be configured to use an incremental SPF algorithm for calculating the shortest path first routes. Incremental SPF is slightly more efficient than the full SPF algorithm, thereby allowing OSPF to converge faster on a new routing topology in reaction to a network event

The following commands are introduced or modified in the feature documented in this module:

- ispf

Chapter 25. OSPF Limit on Number of Redistributed Routes

Open Shortest Path First (OSPF) supports a user-defined maximum number of prefixes (routes) that are allowed to be redistributed into OSPF from other protocols or other OSPF processes. Such a limit could help prevent the router from being flooded by too many redistributed routes.

- Finding Feature Information

- Prerequisites for OSPF Limit on Number of Redistributed Routes

- Information About OSPF Limit on Number of Redistributed Routes

- How to Configure OSPF Limit the Number of OSPF Redistributed Routes

- Configuration Examples for OSPF Limit on Number of Redistributed Routes

- Additional References

- Feature Information for OSPF Limit on Number of Redistributed Routes

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Limit on Number of Redistributed Routes

It is presumed that you have OSPF configured in your network, along with another protocol or another OSPF process you are redistributing.

Information About OSPF Limit on Number of Redistributed Routes

If large number of IP routes are sent into OSPF by redistributing Border Gateway Protocol (BGP) into OSPF, the network can be severely flooded. Limiting the number of redistributed routes prevents this potential problem.

OSPF can receive and accept packets from non-routable addresses (for example, 0.0.0.0/7) also.

How to Configure OSPF Limit the Number of OSPF Redistributed Routes

This section contains the following procedures, which are mutually exclusive. That is, you cannot both limit redistributed prefixes and also choose to be warned.

- Limiting the Number of OSPF Redistributed Routes

- Requesting a Warning About the Number of Routes Redistributed into OSPF

Limiting the Number of OSPF Redistributed Routes

This task describes how to limit the number of OSPF redistributed routes. If the number of redistributed routes reaches the maximum value configured, no more routes will be redistributed.

The redistribution limit applies to all IP redistributed prefixes, including summarized ones. The redistribution limit does not apply to default routes or prefixes that are generated as a result of Type-7 to Type-5 translation.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    redistribute protocol [process-id][as-number] [metric metric-value] [metric-type type-value] [match{internal| external 1| external 2}][tag tag-value] [route-map map-tag] [subnets]

5.    redistribute maximum-prefix maximum [threshold]

6.    end

7.    show ip ospf [process-id]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Router(config)# router ospf 1

Configures an OSPF routing process.

Step 4

redistribute protocol [process-id][as-number] [metric metric-value] [metric-type type-value] [match{internal| external 1| external 2}][tag tag-value] [route-map map-tag] [subnets]

Example:

Router(config-router)# redistribute eigrp 10

Redistributes routes from one routing domain into another routing domain.

Step 5

redistribute maximum-prefix maximum [threshold]

Example:

Router(config-router)# redistribute maximum-prefix 100 80

Sets a maximum number of IP prefixes that are allowed to be redistributed into OSPF.

- There is no default value for the maximum argument.

- The threshold value defaults to 75 percent.

Note:
If the warning-only keyword had been configured in this command, no limit would be enforced; a warning message is simply logged.

Step 6

end

Example:

Router(config-router)# end

Exits router configuration mode.

Step 7

show ip ospf [process-id]

Example:

Router# show ip ospf 1

(Optional) Displays general information about OSPF routing processes.

- If a redistribution limit was configured, the output will include the maximum limit of redistributed prefixes and the threshold for warning messages.

Requesting a Warning About the Number of Routes Redistributed into OSPF

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    redistribute protocol [process-id][as-number] [metric metric-value] [metric-type type-value] [match{internal| external 1| external 2}][tag tag-value] [route-map map-tag] [subnets]

5.    redistribute maximum-prefix maximum [threshold] warning-only

6.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Router(config)# router ospf 1

Configures an OSPF routing process.

Step 4

redistribute protocol [process-id][as-number] [metric metric-value] [metric-type type-value] [match{internal| external 1| external 2}][tag tag-value] [route-map map-tag] [subnets]

Example:

Router(config-router)# redistribute eigrp 10

Redistributes routes from one routing domain into another routing domain.

Note:
The redistribution count applies to external IP prefixes, including summarized routes. Default routes and prefixes that are generated as a result of Type-7 to Type-5 translation are not considered.

Step 5

redistribute maximum-prefix maximum [threshold] warning-only

Example:

Router(config-router)# redistribute maximum-prefix 1000 80 warning-only

Causes a warning message to be logged when the maximum number of IP prefixes has been redistributed into OSPF.

- Because the warning-only keyword is included, no limit is imposed on the number of redistributed prefixes into OSPF.

- There is no default value for the maximum argument.

- The threshold value defaults to 75 percent.

- This example causes two warnings: one at 80 percent of 1000 (800 routes redistributed) and another at 1000 routes redistributed.

Step 6

end

Example:

Router(config-router)# end

Exits router configuration mode.

Configuration Examples for OSPF Limit on Number of Redistributed Routes

- Example OSPF Limit on Number of Redistributed Routes

- Example Requesting a Warning About the Number of Redistributed Routes

Example OSPF Limit on Number of Redistributed Routes

This example sets a maximum of 1200 prefixes that can be redistributed into OSPF process 1. Prior to reaching the limit, when the number of prefixes redistributed reaches 80 percent of 1200 (960 prefixes), a warning message is logged. Another warning is logged when the limit is reached and no more routes are redistributed.

router ospf 1
router-id 10.0.0.1
domain-id 5.6.7.8
log-adjacency-changes
timers lsa-interval 2
network 10.0.0.1 0.0.0.0 area 0
network 10.1.5.1 0.0.0.0 area 0
network 10.2.2.1 0.0.0.0 area 0
redistribute static subnets
redistribute maximum-prefix 1200 80

Example Requesting a Warning About the Number of Redistributed Routes

This example allows two warning messages to be logged, the first if the number of prefixes redistributed reaches 85 percent of 600 (510 prefixes), and the second if the number of redistributed routes reaches 600. However, the number of redistributed routes is not limited.

router ospf 1
network 10.0.0.0 0.0.0.255 area 0
redistribute eigrp 10 subnets
redistribute maximum-prefix 600 85 warning-only

Additional References

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Limit on Number of Redistributed Routes

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Limit on Number of Redistributed Routes

Feature Name

Releases

Feature Information

OSPF Limit on Number of Redistributed Routes

12.0(25)S 12.3(2)T 12.2(18)S 12.2(27)SBC Cisco IOS XE 3.1.0 SG

OSPF supports a user-defined maximum number of prefixes (routes) that are allowed to be redistributed into OSPF from other protocols or other OSPF processes. Such a limit could help prevent the router from being flooded by too many redistributed routes.

The following commands are introduced or modified in the feature documented in this module:

- redistribute maximum-prefix

- show ip ospf

- show ip ospf database

Chapter 26. OSPFv3 Max-Metric Router LSA

The Open Shortest Path First version 3 (OSPFv3) max-metric router link-state advertisement (LSA) feature enables OSPFv3 to advertise its locally generated router LSAs with a maximum metric. The feature allows OSPFv3 processes to converge but not attract transit traffic through the device if there are better alternate paths.

- Finding Feature Information

- Information About OSPFv3 Max-Metric Router LSA

- How to Configure OSPFv3 Max-Metric Router LSA

- Configuration Examples for OSPFv3 Max-Metric Router LSA

- Additional References

- Feature Information for OSPFv3 Max-Metric Router LSA

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPFv3 Max-Metric Router LSA

- OSPFv3 Max-Metric Router LSA

OSPFv3 Max-Metric Router LSA

The OSPFv3 max-metric router LSA feature enables OSPFv3 to advertise its locally generated router LSAs with a maximum metric. The feature allows OSPFv3 processes to converge but not attract transit traffic through the device if there are better alternate paths. After a specified timeout or a notification from Border Gateway Protocol (BGP), OSPFv3 advertises the LSAs with normal metrics.

The max-metric LSA control places the OSPFv3 router into the stub router role using its LSA advertisement. A stub router only forwards packets destined to go to its directly connected links. In OSPFv3 networks, a device could become a stub router by advertising large metrics for its connected links, so that the cost of a path through this device becomes larger than that of an alternative path. OSPFv3 stub router advertisement allows a device to advertise the infinity metric (0xFFFF) for its connected links in router LSAs and advertise the normal interface cost if the link is a stub network.

How to Configure OSPFv3 Max-Metric Router LSA

- Configuring the OSPFv3 Max-Metric Router LSA

Configuring the OSPFv3 Max-Metric Router LSA

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 process-id

4.    address-family ipv6 unicast

5.    max-metric router-lsa [external-lsa [max-metric-value]] [include-stub] [inter-area-lsas [max-metric-value]] [on-startup {seconds | wait-for-bgp}] [prefix-lsa] [stub-prefix-lsa [max-metric-value]] [summary-lsa [max-metric-value]]

6.    end

7.    show ospfv3 [process-id] max-metric

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 process-id

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode.

Step 4

address-family ipv6 unicast

Example:

Device(config)# address-family ipv6 unicast

Configures an instance of the OSPFv3 process in the IPv6 address family.

Step 5

max-metric router-lsa [external-lsa [max-metric-value]] [include-stub] [inter-area-lsas [max-metric-value]] [on-startup {seconds | wait-for-bgp}] [prefix-lsa] [stub-prefix-lsa [max-metric-value]] [summary-lsa [max-metric-value]]

Example:

Device(config-router-af)# max-metric router-lsa on-startup wait-for-bgp

Configures a device that is running the OSPFv3 protocol to advertise a maximum metric so that other devices do not prefer the device as an intermediate hop in their SPF calculations.

Step 6

end

Example:

Device(config-router-af)# end

Exits address family configuration mode and returns to privileged EXEC mode.

Step 7

show ospfv3 [process-id] max-metric

Example:

Device# show ospfv3 1 max-metric

Displays OSPFv3 maximum metric origination information.

Configuration Examples for OSPFv3 Max-Metric Router LSA

- Example: Verifying the OSPFv3 Max-Metric Router LSA

Example: Verifying the OSPFv3 Max-Metric Router LSA

Router# show ipv6 ospf max-metric

OSPFv3 Router with ID (192.1.1.1) (Process ID 1)

Start time: 00:00:05.886, Time elapsed: 3d02h
Originating router-LSAs with maximum metric
Condition: always, State: active

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

OSPFv3 Max-Metric Router LSA

“OSPF Link-State Advertisement Throttling ” module

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 Max-Metric Router LSA

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 Max-Metric Router LSA

Feature Name

Releases

Feature Information

OSPFv3 Max-Metric Router LSA

15.2(1)T

The OSPFv3 max-metric router LSA feature enables OSPF to advertise its locally generated router LSAs with a maximum metric.

The following commands were introduced or modified: max-metric router-lsa, show ipv6 ospf max-metric, show ospfv3 max-metric.

Chapter 27. OSPF Link-State Advertisement Throttling

The OSPF Link-State Advertisement (LSA) Throttling feature provides a dynamic mechanism to slow down link-state advertisement (LSA) updates in OSPF during times of network instability. It also allows faster Open Shortest Path First (OSPF) convergence by providing LSA rate limiting in milliseconds.

History for the OSPF LSA Throttling Feature

Release

Modification

12.0(25)S

This feature was introduced.

12.3(2)T

This feature was integrated into Cisco IOS Release 12.3(2)T.

12.2(18)S

This feature was integrated into Cisco IOS Release 12.2(18)S.

12.2(27)SBC

This feature was integrated into Cisco IOS Release 12.2(27)SBC.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at Click Here . You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

- Finding Feature Information

- Prerequisites for OSPF LSA Throttling

- Information About OSPF LSA Throttling

- How to Customize OSPF LSA Throttling

- Configuration Examples for OSPF LSA Throttling

- Additional References

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF LSA Throttling

It is presumed that you have OSPF configured in your network.

Information About OSPF LSA Throttling

- Benefits of OSPF LSA Throttling

- How OSPF LSA Throttling Works

Benefits of OSPF LSA Throttling

Prior to the OSPF LSA Throttling feature, LSA generation was rate-limited for 5 seconds. That meant that changes in an LSA could not be propagated in milliseconds, so the OSPF network could not achieve millisecond convergence.

The OSPF LSA Throttling feature is enabled by default and allows faster OSPF convergence (in milliseconds). This feature can be customized. One command controls the generation (sending) of LSAs and another command controls the receiving interval. This feature also provides a dynamic mechanism to slow down the frequency of LSA updates in OSPF during times of network instability.

How OSPF LSA Throttling Works

The timers throttle lsa all command controls the generation (sending) of LSAs. The first LSA is always generated immediately upon an OSPF topology change, and the next LSA generated is controlled by the minimum start interval. The subsequent LSAs generated for the same LSA are rate-limited until the maximum interval is reached. The "same LSA" is defined as an LSA instance that contains the same LSA ID number, LSA type, and advertising router ID.

The timers lsa arrival command controls the minimum interval for accepting the same LSA. If an instance of the same LSA arrives sooner than the interval that is set, the LSA is dropped. It is recommended that the arrival interval be less than or equal to the hold-time interval of the timers throttle lsa all command.

How to Customize OSPF LSA Throttling

- Customizing OSPF LSA Throttling

Customizing OSPF LSA Throttling

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    timers throttle lsa all start-interval hold-interval max-interval

5.    timers lsa arrival milliseconds

6.    end

7.    show ip ospf timers rate-limit

8.    show ip ospf

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Router(config)# router ospf 1

Configures an OSPF routing process.

Step 4

timers throttle lsa all start-interval hold-interval max-interval

Example:

Router(config-router)# timers throttle lsa all 100 10000 45000

(Optional) Sets the rate-limiting values (in milliseconds) for LSA generation.

- The default values are as follows:

- start-intervalis 0 milliseconds

- hold-intervalis 5000 milliseconds

- max-intervalis 5000 milliseconds

Step 5

timers lsa arrival milliseconds

Example:

Router(config-router)# timers lsa arrival 2000

(Optional) Sets the minimum interval (in milliseconds) between instances of receiving the same LSA.

- The default value is 1000 milliseconds.

- We suggest you keep the millisecondsvalue of the LSA arrival timer less than or equal to the neighbors’ hold-interval value of the timers throttle lsa all command.

Step 6

end

Example:

Router(config-router)# end

Exits router configuration mode.

Step 7

show ip ospf timers rate-limit

Example:

Router# show ip ospf timers rate-limit

Example:

LSAID: 10.1.1.1    Type: 1   Adv Rtr: 172.16.2.2 Due in: 00:00:00.028

Example:

LSAID: 192.168.4.1   Type: 3   Adv Rtr: 172.17.2.2 Due in: 00:00:00.028

(Optional) Displays a list of the LSAs in the rate limit queue (about to be generated).

- The example shows two LSAs in the queue. Each LSA is identified by LSA ID number, Type (of LSA), Advertising router ID, and the time in hours:minutes:seconds (to the milliseconds) when the LSA is due to be generated.

Step 8

show ip ospf

Example:

Router# show ip ospf

Example:

Routing Process "ospf 4" with ID 10.10.24.4

Example:

Supports only single TOS(TOS0) routes

Example:

Supports opaque LSA

Example:

Supports Link-local Signaling (LLS)

Example:

Initial SPF schedule delay 5000 msecs

Example:

Minimum hold time between two consecutive SPFs 10000 msecs

Example:

Maximum wait time between two consecutive SPFs 10000 msecs

Example:

Incremental-SPF disabled

Example:

Initial LSA throttle delay 100 msecs

Example:

Minimum hold time for LSA throttle 10000 msecs

Example:

Maximum wait time for LSA throttle 45000 msecs

Example:

Minimum LSA arrival 1000 msecs

Example:

LSA group pacing timer 240 secs

Example:

Interface flood pacing timer 33 msecs

Example:

Retransmission pacing timer 66 msecs

Example:

Number of external LSA 0. Checksum Sum 0x0

Example:

Number of opaque AS LSA 0. Checksum Sum 0x0

Example:

Number of DCbitless external and opaque AS LSA 0

Example:

Number of DoNotAge external and opaque AS LSA 0

Example:

Number of areas in this router is 1. 1 normal 0 stub 0 nssa

Example:

External flood list length 0

Example:

Area 24

Example:

Number of interfaces in this area is 2

Example:

Area has no authentication

Example:

SPF algorithm last executed 04:28:18.396 ago

Example:

SPF algorithm executed 8 times

Example:

Area ranges are

Example:

Number of LSA 4. Checksum Sum 0x23EB9

Example:

Number of opaque link LSA 0. Checksum Sum 0x0

Example:

Number of DCbitless LSA 0

Example:

Number of indication LSA 0

Example:

Number of DoNotAge LSA 0

Example:

Flood list length 0

(Optional) Displays information about OSPF.

- The output lines shown in bold in the example indicate the LSA throttling values.

Configuration Examples for OSPF LSA Throttling

- Example OSPF LSA Throttling

Example OSPF LSA Throttling

This example customizes OSPF LSA throttling so that the start interval is 200 milliseconds, the hold interval is 10,000 milliseconds, and the maximum interval is 45,000 milliseconds. The minimum interval between instances of receiving the same LSA is 2000 milliseconds.

router ospf 1
log-adjacency-changes
timers throttle lsa all 200 10000 45000
timers lsa arrival 2000
network 10.10.4.0 0.0.0.255 area 24
network 10.10.24.0 0.0.0.255 area 24

Additional References

The following sections provide references related to OSPF LSA throttling.

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

OSPFv3 Max-Metric Router LSA

“OSPFv3 Max-Metric Router LSA ” module

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Chapter 28. OSPF Support for Unlimited Software VRFs per PE Router

In a Multiprotocol Label Switching--Virtual Private Network (MPLS-VPN) deployment, each VPN routing and forwarding instance (VRF) needs a separate Open Shortest Path First (OSPF) process when configured to run OSPF. The OSPF Support for Unlimited Software VRFs per Provider Edge (PE) Router feature addresses the scalability issue for OSPF VPNs by eliminating the OSPF VPN limit of 32 processes.

History for the OSPF Support for Unlimited Software VRFs per Provider Edge Router Feature

Release

Modification

12.3(4)T

This feature was introduced.

12.0(27)S

This feature was integrated into Cisco IOS Release 12.0(27)S.

12.2(25)S

This feature was integrated into Cisco IOS Release 12.2(25)S.

12.2(18)SXE

This feature was integrated into Cisco IOS Release 12.2(18)SXE.

12.2(27)SBC

This feature was integrated into Cisco IOS Release 12.2(27)SBC.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at Click Here . You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

- Finding Feature Information

- Prerequisites for OSPF Support for Unlimited Software VRFs per PE Router

- Restrictions for OSPF Support for Unlimited Software VRFs per PE Router

- Information About OSPF Support for Unlimited Software VRFs per PE Router

- How to Configure OSPF Support for Unlimited Software VRFs per PE Router

- Configuration Examples for OSPF Support for Unlimited Software VRFs per PE Router

- Additional References

- Glossary

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Support for Unlimited Software VRFs per PE Router

You must have OSPF configured in your network.

Restrictions for OSPF Support for Unlimited Software VRFs per PE Router

Only 32 processes per VRF can be supported. For different VRF processes, there is no limit.

Information About OSPF Support for Unlimited Software VRFs per PE Router

Before Cisco IOS Releases 12.3(4)T and 12.0(27)S, a separate OSPF process was necessary for each VRF that receives VPN routes via OSPF. When VPNs are deployed, an MPLS Provider Edge (PE) router will be running both multiprotocol Border Gateway Protocol (BGP) for VPN distribution, and Interior Gateway Protocol (IGP) for PE-P connectivity. It is a common scenario when OSPF is used as the IGP between a customer edge (CE) router and a PE router. OSPF was not scalable in VPN deployment because of the limit of 32 processes. By default one process is used for connected routes and another process is used for static routes, therefore only 28 processes can be created for VRFs.

The OSPF Support for Unlimited Software VRFs per Provider Edge Router feature allows for an approximate range of 300 to 10,000 VRFs, depending on the particular platform and on the applications, processes, and protocols that are currently running on the platform.

How to Configure OSPF Support for Unlimited Software VRFs per PE Router

- Configuring and Verifying Unlimited Software VRFs per Provider Edge Router

Configuring and Verifying Unlimited Software VRFs per Provider Edge Router

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id [vrf vpn-name]

4.    end

5.    show ip ospf [process-id]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id [vrf vpn-name]

Example:

Router(config)# router ospf 1 vrf crf-1

Enables OSPF routing.

- The process-id argument identifies the OSPF process.

- Use the vrf keyword and vpn-name argument to identify a VPN.

Note:
You now can configure as many OSPF VRF processes as needed.

Step 4

end

Example:

Router(config-router)# end

Returns to privileged EXEC mode.

Step 5

show ip ospf [process-id]

Example:

Router# show ip ospf 1

Displays general information about OSPF routing processes.

Configuration Examples for OSPF Support for Unlimited Software VRFs per PE Router

- Example Configuring OSPF Support for Unlimited Software VRFs per PE Router

- Example Verifying OSPF Support for Unlimited Software VRFs per PE Router

Example Configuring OSPF Support for Unlimited Software VRFs per PE Router

This example shows a basic OSPF configuration using the router ospf command to configure OSPF VRF processes for the VRFs first, second, and third:

Router> enable
Router# configure terminal
Router(config)# router ospf 12 vrf first
Router(config)# router ospf 13 vrf second
Router(config)# router ospf 14 vrf third
Router(config)#
exit

Example Verifying OSPF Support for Unlimited Software VRFs per PE Router

This example illustrates the output display from the show ip ospf command to verify that the OSPF VRF process 12 has been created for the VRF named first. The output that relates to the VRF first appears in bold.

Router# show ip ospf 12
main ID type 0x0005, value 0.0.0.100
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Connected to MPLS VPN Superbackbone, VRF first
It is an area border router
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Incremental-SPF disabled
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 0. Checksum Sum 0x0
Number of opaque AS LSA 0. Checksum Sum 0x0
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Number of areas transit capable is 0
External flood list length 0
Area BACKBONE(0)
Number of interfaces in this area is 1
Area has no authentication
SPF algorithm last executed 00:00:15.204 ago
SPF algorithm executed 2 times
Area ranges are
Number of LSA 1. Checksum Sum 0xD9F3
Number of opaque link LSA 0. Checksum Sum 0x0
Number of DCbitless LSA 0
Number of indication LSA 0
Number of DoNotAge LSA 0
Flood list length 0

Additional References

The following sections provide references related to the OSPF Support for Unlimited Software VRFs per Provider Edge Router feature.

Related Documents

Related Topic

Document Title

Configuring OSPF

Cisco IOS IP Routing: OSPF Configuration Guide

Standards

Standards

Title

None

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

None

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Glossary

multiprotocol BGP --Border Gateway Protocol (BGP) can be used as an interdomain routing protocol in networks that use Connectionless Network Service (CLNS) as the network-layer protocol.

Chapter 29. OSPF Area Transit Capability

The OSPF Area Transit Capability feature provides an OSPF Area Border Router (ABR) with the ability to discover shorter paths through the transit area for forwarding traffic that would normally need to travel through the virtual-link path. This functionality allows Cisco IOS software to be compliant with RFC 2328.

- Finding Feature Information

- Information About OSPF Area Transit Capability

- How to Disable OSPF Area Transit Capability

- Additional References

- Feature Information for OSPF Area Transit Capability

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPF Area Transit Capability

The OSPF Area Transit Capability feature is enabled by default. RFC 2328 defines OSPF area transit capability as the ability of the area to carry data traffic that neither originates nor terminates in the area itself. This capability enables the OSPF ABR to discover shorter paths through the transit area and forward traffic along those paths rather than using the virtual link or path, which are not as optimal.

For a detailed description of OSPF area transit capability, see RFC 2328, OSPF Version 2, at the following URL:

Click Here

How to Disable OSPF Area Transit Capability

- Disabling OSPF Area Transit Capability on an Area Border Router

Disabling OSPF Area Transit Capability on an Area Border Router

This task describes how to disable the OSPF Area Transit Capability feature on an OSPF ABR.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id [vrf vpn-name]

4.    no capability transit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id [vrf vpn-name]

Example:

Router(config)# router ospf 100

Enables OSPF routing and enters router configuration mode.

- The process-id argument identifies the OSPF process.

Step 4

no capability transit

Example:

Router(config-router)# no capability transit

Disables OSPF area capability transit on all areas for a router process.

Additional References

Related Documents

Related Topic

Document Title

Configuring OSPF

"Configuring OSPF" module

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

RFC 2328

OSPF Version 2

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Area Transit Capability

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Area Transit Capability

Feature Name

Releases

Feature Information

OSPF Area Transit Capability

12.0(27)S 12.3(7)T 12.2(25)S 12.2(27)SBC 12.2(33)SRA 12.2(33)SXH Cisco IOS XE 3.1.0 SG

The OSPF Area Transit Capability feature provides an OSPF Area Border Router (ABR) the ability to discover shorter paths through the transit area for forwarding traffic that would normally need to travel through the virtual-link path. This functionality allows Cisco IOS software to be compliant with RFC 2328.

The following commands are introduced or modified in the feature documented in this module:

- capability transit

Chapter 30. OSPF Per-Interface Link-Local Signaling

The OSPF Per-Interface Link-Local Signaling feature allows you to selectively enable or disable Link-Local Signaling (LLS) for a specific interface regardless of the global (router level) setting that you have previously configured.

- Finding Feature Information

- Information About OSPF Per-Interface Link-Local Signaling

- How to Configure OSPF Per-Interface Link-Local Signaling

- Configuration Examples for OSPF Per-Interface Link-Local Signaling

- Additional References

- Feature Information for OSPF Per-Interface Link-Local Signaling

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPF Per-Interface Link-Local Signaling

- Benefits of the OSPF Per-Interface Link-Local Signaling Feature

Benefits of the OSPF Per-Interface Link-Local Signaling Feature

LLS allows for the extension of existing OSPF packets in order to provide additional bit space. The additional bit space enables greater information per packet exchange between OSPF neighbors. This functionality is used, for example, by the OSPF Nonstop Forwarding (NSF) Awareness feature that allows customer premises equipment (CPE) routers that are NSF-aware to help NSF-capable routers perform nonstop forwarding of packets.

When LLS is enabled at the router level, it is automatically enabled for all interfaces. The OSPF Per-Interface Link-Local Signaling feature allows you to selectively enable or disable LLS for a specific interface. You may want to disable LLS on a per-interface basis depending on your network design. For example, disabling LLS on an interface that is connected to a non-Cisco device that may be noncompliant with RFC 2328 can prevent problems with the forming of Open Shortest Path First (OSPF) neighbors in the network.

How to Configure OSPF Per-Interface Link-Local Signaling

- Turning Off LLS on a Per-Interface Basis

Turning Off LLS on a Per-Interface Basis

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type slot /port

4.    ip address ip-address mask [secondary]

5.    no ip directed-broadcast [access-list-number | extended access-list-number]

6.    ip ospf message-digest-key key-id encryption-type md5 key

7.    [no | default] ip ospf lls [disable]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface type slot /port

Example:

Router(config)# interface Ethernet 1/0

Example:

Configures an interface type and enters interface configuration mode.

Step 4

ip address ip-address mask [secondary]

Example:

Router(config-if)# ip address 10.2.145.20 255.255.255.0

Sets a primary or secondary IP address for an interface.

Step 5

no ip directed-broadcast [access-list-number | extended access-list-number]

Example:

Router(config-if)# no ip directed-broadcast

Drops directed broadcasts destined for the subnet to which that interface is attached, rather than broadcasting them.

- The forwarding of IP directed broadcasts on Ethernet interface 1/0 is disabled.

Step 6

ip ospf message-digest-key key-id encryption-type md5 key

Example:

Router(config-if)# ip ospf message-digest-key 100 md5 testing

Enables OSPF Message Digest 5 (MD5) algorithm authentication.

Step 7

[no | default] ip ospf lls [disable]

Example:

Router(config-if)# ip ospf lls disable

Disables LLS on an interface, regardless of the global (router level) setting.

- What to Do Next

What to Do Next

To verify that LLS has been enabled or disabled for a specific interface, use the show ip ospf interface command. See the "Example: Configuring and Verifying the OSPF Per-Interface Link-Local Signaling Feature" section for an example of the information displayed.

Configuration Examples for OSPF Per-Interface Link-Local Signaling

- Example OSPF Per-Interface Link-Local Signaling

Example OSPF Per-Interface Link-Local Signaling

In the following example, LLS has been enabled on Ethernet interface 1/0 and disabled on Ethernet interface 2/0:

interface Ethernet1/0
ip address 10.2.145.2 255.255.255.0
no ip directed-broadcast
ip ospf message-digest-key 1 md5 testing
ip ospf lls
!
interface Ethernet2/0
ip address 10.1.145.2 255.255.0.0
no ip directed-broadcast
ip ospf message-digest-key 1 md5 testing
!
ip ospf lls disable
interface Ethernet3/0
ip address 10.3.145.2 255.255.255.0
no ip directed-broadcast
!
router ospf 1
log-adjacency-changes detail
area 0 authentication message-digest
redistribute connected subnets
network 10.0.0.0 0.255.255.255 area 1
network 10.2.3.0 0.0.0.255 area 1

In the following example, the show ip ospf interface command has been entered to verify that LLS has been enabled for Ethernet interface 1/0 and disabled for interface Ethernet 2/0:

Router# show ip ospf interface
Ethernet1/0 is up, line protocol is up
Internet Address 10.2.145.2/24, Area 1
Process ID 1, Router ID 10.22.222.2, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 10.2.2.3, Interface address 10.2.145.1
Backup Designated router (ID) 10.22.222.2, Interface address 10.2.145.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:00
!   Supports Link-local Signaling (LLS)
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 2, maximum is 8
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.2.2.3  (Designated Router)
Suppress hello for 0 neighbor(s)
Ethernet2/0 is up, line protocol is up
Internet Address 10.1.145.2/16, Area 1
Process ID 1, Router ID 10.22.222.2, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 10.2.2.3, Interface address 10.1.145.1
Backup Designated router (ID) 10.22.222.2, Interface address 10.1.145.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:04
!   Does not support Link-local Signaling (LLS)
Index 2/2, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 2, maximum is 11
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 45.2.2.3  (Designated Router)
Suppress hello for 0 neighbor(s)
Ethernet3/0 is up, line protocol is up
Internet Address 10.3.145.2/24, Area 1
Process ID 1, Router ID 10.22.222.2, Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 10.2.2.3, Interface address 10.3.145.1
Backup Designated router (ID) 10.22.222.2, Interface address 10.3.145.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:07
!   Supports Link-local Signaling (LLS)
Index 3/3, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 2, maximum is 11
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.2.2.3  (Designated Router)
Suppress hello for 0 neighbor(s)

Additional References

The following sections provide references related to the OSPF Per-Interface Link-Local Signaling feature.

Related Documents

Related Topic

Document Title

Configuring OSPF

"Configuring OSPF"

Configuring OSPF NSF Awareness

"NSF-OSPF"

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Standards

Standards

Title

None

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

RFC 2328

OSPF Version 2

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Per-Interface Link-Local Signaling

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Per-Interface Link-Local Signaling

Feature Name

Releases

Feature Information

OSPF Per-Interface Link-Local Signaling

12.0(27)S 12.3(7)T 12.2(25)S 12.2(18)SXE 12.2(27)SBC 12.2(33)SRA

The OSPF Per-Interface Link-Local Signaling feature allows you to selectively enable or disable Link-Local Signaling (LLS) for a specific interface regardless of the global (router level) setting that you have previously configured.

The following command was introduced or modified: ip ospf lls.

Chapter 31. OSPF Link-State Database Overload Protection

The OSPF Link-State Database Overload Protection feature allows you to limit the number of nonself-generated link-state advertisements (LSAs) for a given Open Shortest Path First (OSPF) process. Excessive LSAs generated by other routers in the OSPF domain can substantially drain the CPU and memory resources of the router.

History for the OSPF Link-State Database Overload Protection Feature

Release

Modification

12.0(27)S

This feature was introduced.

12.3(7)T

This feature was integrated into Cisco IOS Release 12.3(7)T.

12.2(25)S

This feature was integrated into Cisco IOS Release 12.2(25)S.

12.2(18)SXE

This feature was integrated into Cisco IOS Release 12.2(18)SXE.

12.2(27)SBC

This feature was integrated into Cisco IOS Release 12.2(27)SBC.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at Click Here . You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

- Finding Feature Information

- Prerequisites for OSPF Link-State Database Overload Protection

- Information About OSPF Link-State Database Overload Protection

- How to Configure OSPF Link-State Database Overload Protection

- Configuration Examples for OSPF Link-State Database Overload Protection

- Additional References

- Glossary

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Link-State Database Overload Protection

It is presumed you have OSPF running on your network.

Information About OSPF Link-State Database Overload Protection

- Benefits of Using OSPF Link-State Database Overload Protection

- How OSPF Link-State Database Overload Protection Works

Benefits of Using OSPF Link-State Database Overload Protection

The OSPF Link-State Database Overload Protection feature provides a mechanism at the OSPF level to limit the number of nonself-generated LSAs for a given OSPF process. When other routers in the network have been misconfigured, they may generate a high volume of LSAs, for instance, to redistribute large numbers of prefixes. This protection mechanism prevents routers from receiving a large number of LSAs and therefore experiencing CPU and memory shortages.

How OSPF Link-State Database Overload Protection Works

When the OSPF Link-State Database Overload Protection feature is enabled, the router keeps a count of the number of received (nonself-generated) LSAs it has received. When the configured threshold number of LSAs is reached, an error message is logged. When the configured maximum number of LSAs is exceeded, the router will send a notification. If the count of received LSAs is still higher than the configured maximum after one minute, the OSPF process takes down all adjacencies and clears the OSPF database. In this ignore state, all OSPF packets received on any interface that belongs to this OSPF process are ignored and no OSPF packets are generated on any of these interfaces. The OSPF process remains in the ignore state for the time configured by the ignore-time keyword of the max-lsa command. Each time the OSPF process gets into an ignore state a counter is incremented. If this counter exceeds the number counts configured by the ignore-count keyword, the OSPF process stays permanently in the same ignore state and manual intervention is required to get the OSPF process out of the ignore state. The ignore state counter is reset to 0 when the OSPF process remains in the normal state of operation for the amount of time that was specified by the reset-time keyword.

If the warning-only keyword of the max-lsa command has been configured, the OSPF process will send only a warning that the LSA maximum has been exceeded.

How to Configure OSPF Link-State Database Overload Protection

- Limiting the Number of NonSelf-Generating LSAs for an OSPF Process

Limiting the Number of NonSelf-Generating LSAs for an OSPF Process

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id

4.    router-id ip-address

5.    log -adjacency-changes [detail]

6.    max-lsa maximum-number [threshold-percentage] [warning-only] [ignore-time minutes] [ignore-count count-number] [reset-time minutes]

7.    network ip-address wildcard-mask area area-id

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id

Example:

Router(config)# router ospf 1

Enables OSPF routing.

- The process-id argument identifies the OSPF process.

Step 4

router-id ip-address

Example:

Router(config-router)# router-id 10.0.0.1

Specifies a fixed router ID for an OSPF process.

Step 5

log -adjacency-changes [detail]

Example:

Router(config-router)# log-adjacency-changes

Configures the router to send a syslog message when an OSPF neighbor goes up or down.

Step 6

max-lsa maximum-number [threshold-percentage] [warning-only] [ignore-time minutes] [ignore-count count-number] [reset-time minutes]

Example:

Router(config-router)# max-lsa 12000

Limits the number of nonself-generated LSAs an OSPF routing process can keep in the OSPF link-state database (LSDB).

Step 7

network ip-address wildcard-mask area area-id

Example:

Router(config-router)# network 209.165.201.1 255.255.255.255 area 0

Defines the interfaces on which OSPF runs and defines the area ID for those interfaces.

- Verifying the Number of Nonself-Generated LSAs on a Router

Verifying the Number of Nonself-Generated LSAs on a Router

The show ip ospf command is entered with the database-summary keyword to verify the actual number of nonself-generated LSAs on a router. This command can be used at any given point in time to display lists of information related to the OSPF database for a specific router.

Router# show ip ospf 2000 database database-summary

OSPF Router with ID (192.168.1.3) (Process ID 2000)
Area 0 database summary
LSA Type      Count    Delete   Maxage
Router        5        0        0
Network       2        0        0
Summary Net   8        2        2
Summary ASBR  0        0        0
Type-7 Ext    0        0        0
Prefixes redistributed in Type-7  0
Opaque Link   0        0        0
Opaque Area   0        0        0
Subtotal      15       2        2
Process 2000 database summary
LSA Type      Count    Delete   Maxage
Router        5        0        0
Network       2        0        0
Summary Net   8        2        2
Summary ASBR  0        0        0
Type-7 Ext    0        0        0
Opaque Link   0        0        0
Opaque Area   0        0        0
Type-5 Ext    4        0        0
Prefixes redistributed in Type-5  0
Opaque AS     0        0        0
Non-self      16
Total         19       2        2

Configuration Examples for OSPF Link-State Database Overload Protection

- Example Setting a Limit for LSA Generation

Example Setting a Limit for LSA Generation

In the following example, the router is configured to not accept any more nonself-generated LSAs once a maximum of 14,000 has been exceeded:

Router(config)# router ospf 1
Router(config-router)# router-id 192.168.0.1
Router(config-router)# log-adjacency-changes
Router(config-router)# max-lsa 14000
Router(config-router)# area 33 nssa
Router(config-router)# network 192.168.0.1 0.0.0.0 area 1
Router(config-router)# network 192.168.5.1 0.0.0.0 area 1
Router(config-router)# network 192.168.2.1 0.0.0.0 area 0

In the following example, the show ip ospf command has been entered to confirm the configuration:

Router# show ip ospf 1
Routing Process "ospf 1" with ID 192.168.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Maximum number of non self-generated LSA allowed 14000
Threshold for warning message 75%
Ignore-time 5 minutes, reset-time 10 minutes
Ignore-count allowed 5, current ignore-count 0
It is an area border and autonomous system boundary router

In the following example, the following output appears when the show ip ospf command has been entered during the time when the router is in the ignore state:

Router# show ip ospf 1
Routing Process "ospf 1" with ID 192.168.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Maximum number of non self-generated LSA allowed 14000
Threshold for warning message 75%
Ignore-time 5 minutes, reset-time 10 minutes
Ignore-count allowed 5, current ignore-count 1
Ignoring all neighbors due to max-lsa limit, time remaining: 00:04:52
It is an area border and autonomous system boundary router

The following output appears when the show ip ospf command has been entered after the router left the ignore state:

Router# show ip ospf 1
Routing Process "ospf 1" with ID 192.168.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Maximum number of non self-generated LSA allowed 14000
Threshold for warning message 75%
Ignore-time 5 minutes, reset-time 10 minutes
Ignore-count allowed 5, current ignore-count 1 - time remaining: 00:09:51
It is an area border and autonomous system boundary router

The following output appears when the show ip ospf command has been entered for a router that is permanently in the ignore state:

Router# show ip ospf 1
Routing Process "ospf 1" with ID 192.168.0.1
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
Maximum number of non self-generated LSA allowed 14000
Threshold for warning message 75%
Ignore-time 5 minutes, reset-time 10 minutes
Ignore-count allowed 5, current ignore-count 6
Permanently ignoring all neighbors due to max-lsa limit
It is an area border and autonomous system boundary router

Additional References

The following sections provide references related to the OSPF Link-State Database Overload Protection feature.

Related Documents

Related Topic

Document Title

Configuring OSPF

- "Configuring OSPF" module

Standards

Standards

Title

None

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFCs

Title

None

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Glossary

LSDB --link-state database.

Chapter 32. OSPF Enhanced Traffic Statistics for OSPFv2 and OSPFv3

This document describes new and modified commands that provide enhanced OSPF traffic statistics for OSPFv2 and OSPFv3. The ability to collect and display more detailed traffic statistics increases high availability for the OSPF network by making the troubleshooting process more efficient.

New OSPF traffic statistics are collected and displayed to include the following information:

- OSPF Hello input queue and OSPF process queue status and statistics.

- Global OSPF traffic statistics.

- Per OSPF interface traffic statistics.

- Per OSPF process traffic statistics.

- Finding Feature Information

- Prerequisites for OSPF Enhanced Traffic Statistics

- Information About OSPF Enhanced Traffic Statistics

- How to Display and Clear OSPF Enhanced Traffic Statistics

- Configuration Examples for OSPF Enhanced Traffic Commands

- Additional References

- Feature Information for OSPF Enhanced Traffic Statistics

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF Enhanced Traffic Statistics

OSPFv2 or OSPFv3 must be configured on the router.

Information About OSPF Enhanced Traffic Statistics

The OSPF enhanced traffic statistics are enabled by default and cannot be disabled. The detailed OSPF traffic statistics are especially beneficial for troubleshooting the following types of OSPF instabilities:

- OSPF process queue status and statistical information can help the network administrator determine if an OSPF process can handle the amount of traffic sent to OSPF.

- OSPF packet header errors and LSA errors statistics keep a record of different errors found in received OSPF packets.

OSPF enhanced traffic control statistics also monitor the amount of traffic control exchanged between OSPF processes--an important consideration in network environments with slow links and frequent topology changes.

How to Display and Clear OSPF Enhanced Traffic Statistics

- Displaying and Clearing OSPF Traffic Statistics for OSPFv2

- Displaying and Clearing OSPF Traffic Statistics for OSPFv3

Displaying and Clearing OSPF Traffic Statistics for OSPFv2

Before You Begin

Your network must run IPv4 to collect, display and clear detailed traffic statistics for Hello output, process queue status, global OSPF traffic statistics, per OSPF interface traffic statistics and per OSPF process traffic statistics.

SUMMARY STEPS

1.    enable

2.    show ip ospf [process-id] traffic[interface-type interface-number]

3.    clear ip ospf traffic

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ip ospf [process-id] traffic[interface-type interface-number]

Example:

Device# show ip ospf traffic

Displays OSPFv2 traffic statistics.

Step 3

clear ip ospf traffic

Example:

Device# clear ip ospf traffic

Clears OSPFv2 traffic statistics.

Displaying and Clearing OSPF Traffic Statistics for OSPFv3

Before You Begin

Your network must run IPv6 to collect, display and clear detailed traffic statistics for Hello output, process queue status, global OSPF traffic statistics, per OSPF interface traffic statistics and per OSPF process traffic statistics.

SUMMARY STEPS

1.    enable

2.    show ipv6 ospf [process-id] traffic[interface-type interface-number]

3.    clear ipv6 ospf traffic

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show ipv6 ospf [process-id] traffic[interface-type interface-number]

Example:

Device# show ipv6 ospf traffic

Displays OSPFv3 traffic statistics.

Step 3

clear ipv6 ospf traffic

Example:

Device# clear ipv6 ospf traffic

Clears OSPFv3 traffic statistics.

Configuration Examples for OSPF Enhanced Traffic Commands

- Displaying and Clearing Enhanced Traffic Statistics for OSPFv2 Example

- Displaying and Clearing Enhanced Traffic Statistics for OSPFv3 Example

Displaying and Clearing Enhanced Traffic Statistics for OSPFv2 Example

The following example shows display output for the show ip ospf traffic command for OSPFv2:

Device# show ip ospf traffic
OSPF statistics:
Rcvd: 55 total, 0 checksum errors
22 hello, 7 database desc, 2 link state req
6 link state updates, 6 link state acks
Sent: 68 total
45 hello, 7 database desc, 2 link state req
10 link state updates, 4 link state acks
OSPF Router with ID (10.1.1.1) (Process ID 8)
OSPF queues statistic for process ID 8:
OSPF Hello queue size 0, no limit, drops 0, max size 0
OSPF Router queue size 0, limit 200, drops 0, max size 0
Interface statistics:
Interface Ethernet0/0.1
OSPF packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      0                    0
RX DB des     0                    0
RX LS req     0                    0
RX LS upd     0                    0
RX LS ack     0                    0
RX Total      0                    0
TX Failed     0                    0
TX Hello      16                   1216
TX DB des     0                    0
TX LS req     0                    0
TX LS upd     0                    0
TX LS ack     0                    0
TX Total      16                   1216
OSPF header errors
Length 0, Checksum 0, Version 0, Bad Source 0,
No Virtual Link 0, Area Mismatch 0, No Sham Link 0,
Self Originated 0, Duplicate ID 0, Hello 0,
MTU Mismatch 0, Nbr Ignored 0, LLS 0,
Authentication 0,
OSPF LSA errors
Type 0, Length 0, Data 0, Checksum 0,
Summary traffic statistics for process ID 8:
OSPF packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      0                    0
RX DB des     0                    0
RX LS req     0                    0
RX LS upd     0                    0
RX LS ack     0                    0
RX Total      0                    0
TX Failed     0                    0
TX Hello      16                   1216
TX DB des     0                    0
TX LS req     0                    0
TX LS upd     0                    0
TX LS ack     0                    0
TX Total      16                   1216
OSPF header errors
Length 0, Checksum 0, Version 0, Bad Source 0,
No Virtual Link 0, Area Mismatch 0, No Sham Link 0,
Self Originated 0, Duplicate ID 0, Hello 0,
MTU Mismatch 0, Nbr Ignored 0, LLS 0,
Authentication 0,
OSPF LSA errors
Type 0, Length 0, Data 0, Checksum 0,
OSPF Router with ID (10.1.1.4) (Process ID 1)
OSPF queues statistic for process ID 1:
OSPF Hello queue size 0, no limit, drops 0, max size 2
OSPF Router queue size 0, limit 200, drops 0, max size 2
Interface statistics:
Interface Serial2/0
OSPF packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      11                   528
RX DB des     4                    148
RX LS req     1                    60
RX LS upd     3                    216
RX LS ack     2                    128
RX Total      21                   1080
TX Failed     0                    0
TX Hello      14                   1104
TX DB des     3                    252
TX LS req     1                    56
TX LS upd     3                    392
TX LS ack     2                    128
TX Total      23                   1932
OSPF header errors
Length 0, Checksum 0, Version 0, Bad Source 0,
No Virtual Link 0, Area Mismatch 0, No Sham Link 0,
Self Originated 0, Duplicate ID 0, Hello 0,
MTU Mismatch 0, Nbr Ignored 0, LLS 0,
Authentication 0,
OSPF LSA errors
Type 0, Length 0, Data 0, Checksum 0,
Interface Ethernet0/0
OSPF packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      13                   620
RX DB des     3                    116
RX LS req     1                    36
RX LS upd     3                    228
RX LS ack     4                    216
RX Total      24                   1216
TX Failed     0                    0
TX Hello      17                   1344
TX DB des     4                    276
TX LS req     1                    56
TX LS upd     7                    656
TX LS ack     2                    128
TX Total      31                   2460
OSPF header errors
Length 0, Checksum 0, Version 0, Bad Source 13,
No Virtual Link 0, Area Mismatch 0, No Sham Link 0,
Self Originated 0, Duplicate ID 0, Hello 0,
MTU Mismatch 0, Nbr Ignored 0, LLS 0,
Authentication 0,
OSPF LSA errors
Type 0, Length 0, Data 0, Checksum 0,

Summary traffic statistics for process ID 1:
OSPF packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      24                   1148
RX DB des     7                    264
RX LS req     2                    96
RX LS upd     6                    444
RX LS ack     6                    344
RX Total      45                   2296
TX Failed     0                    0
TX Hello      31                   2448
TX DB des     7                    528
TX LS req     2                    112
TX LS upd     10                   1048
TX LS ack     4                    256
TX Total      54                   4392
OSPF header errors
Length 0, Checksum 0, Version 0, Bad Source 13,
No Virtual Link 0, Area Mismatch 0, No Sham Link 0,
Self Originated 0, Duplicate ID 0, Hello 0,
MTU Mismatch 0, Nbr Ignored 0, LLS 0,
Authentication 0,
OSPF LSA errors
Type 0, Length 0, Data 0, Checksum 0,

The network administrator can issue the clear ip ospf traffic command to reset all counters and restart all statistics collections:

Device# clear ip ospf traffic

Displaying and Clearing Enhanced Traffic Statistics for OSPFv3 Example

The following example shows display output for the show ipv6 ospf traffic command for OSPFv3:

Device# show ipv6 ospf traffic

OSPFv3 statistics:
Rcvd: 32 total, 0 checksum errors
10 hello, 7 database desc, 2 link state req
9 link state updates, 4 link state acks
0 LSA ignored
Sent: 45 total, 0 failed
17 hello, 12 database desc, 2 link state req
8 link state updates, 6 link state acks
OSPFv3 Router with ID (10.1.1.4) (Process ID 6)
OSPFv3 queues statistic for process ID 6
Hello queue size 0, no limit, max size 2
Router queue size 0, limit 200, drops 0, max size 2
Interface statistics:
Interface Serial2/0
OSPFv3 packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      5                    196
RX DB des     4                    172
RX LS req     1                    52
RX LS upd     4                    320
RX LS ack     2                    112
RX Total      16                   852
TX Failed     0                    0
TX Hello      8                    304
TX DB des     3                    144
TX LS req     1                    52
TX LS upd     3                    252
TX LS ack     3                    148
TX Total      18                   900
OSPFv3 header errors
Length 0, Checksum 0, Version 0, No Virtual Link 0,
Area Mismatch 0, Self Originated 0, Duplicate ID 0,
Instance ID 0, Hello 0, MTU Mismatch 0,
Nbr Ignored 0, Authentication 0,
OSPFv3 LSA errors
Type 0, Length 0, Data 0, Checksum 0,
Interface Ethernet0/0
OSPFv3 packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      6                    240
RX DB des     3                    144
RX LS req     1                    52
RX LS upd     5                    372
RX LS ack     2                    152
RX Total      17                   960
TX Failed     0                    0
TX Hello      11                   420
TX DB des     9                    312
TX LS req     1                    52
TX LS upd     5                    376
TX LS ack     3                    148
TX Total      29                   1308
OSPFv3 header errors
Length 0, Checksum 0, Version 0, No Virtual Link 0,
Area Mismatch 0, Self Originated 0, Duplicate ID 0,
Instance ID 0, Hello 0, MTU Mismatch 0,
Nbr Ignored 0, Authentication 0,
OSPFv3 LSA errors
Type 0, Length 0, Data 0, Checksum 0,
Summary traffic statistics for process ID 6:
OSPFv3 packets received/sent
Type          Packets              Bytes
RX Invalid    0                    0
RX Hello      11                   436
RX DB des     7                    316
RX LS req     2                    104
RX LS upd     9                    692
RX LS ack     4                    264
RX Total      33                   1812
TX Failed     0                    0
TX Hello      19                   724
TX DB des     12                   456
TX LS req     2                    104
TX LS upd     8                    628
TX LS ack     6                    296
TX Total      47                   2208
OSPFv3 header errors
Length 0, Checksum 0, Version 0, No Virtual Link 0,
Area Mismatch 0, Self Originated 0, Duplicate ID 0,
Instance ID 0, Hello 0, MTU Mismatch 0,
Nbr Ignored 0, Authentication 0,
OSPFv3 LSA errors
Type 0, Length 0, Data 0, Checksum 0,

The network administrator can issue the clear ipv6 ospf traffic command to reset all counters and restart all statistics collections:

Device# clear ipv6 ospf traffic

Additional References

The following sections provide references related to the OSPF Enhanced Traffic Statistics for OSPFv2 and OSPFv3 feature.

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

OSPF configuration

Configuring OSPF

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Enhanced Traffic Statistics

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Enhanced Traffic Statistics for OSPFv2 and OSPFv3

Feature Name

Releases

Feature Information

OSPF Enhanced Traffic Statistics for OSPFv2 and OSPFv3

Cisco IOS Release 12.4(6)T

This document describes the detailed OSPF traffic statistics that are provided when the user enters the new and modified commands show commands for OSPFv2 and OSPFv3.

The following commands were introduced or modified: clear ipv6 ospf traffic, show ip ospf traffic, show ipv6 ospf traffic.

Chapter 33. OSPF MIB Support of RFC 1850 and Latest Extensions

The OSPF MIB Support of RFC 1850 and Latest Extensions feature introduces the capability for Simple Network Management Protocol (SNMP) monitoring on the Open Shortest Path First (OSPF) routing protocol. Users have an improved ability to constantly monitor the changing state of an OSPF network by use of MIB objects to gather information relating to protocol parameters and trap notification objects that can signal the occurrence of significant network events such as transition state changes. The protocol information collected by the OSPF MIB objects and trap objects can be used to derive statistics that will help monitor and improve overall network performance.

- Finding Feature Information

- Prerequisites for OSPF MIB Support of RFC 1850 and Latest Extensions

- Restrictions for OSPF MIB Support of RFC 1850 and Latest Extensions

- Information About OSPF MIB Support of RFC 1850 and Latest Extensions

- How to Enable OSPF MIB Support of RFC 1850 and Latest Extensions

- Configuration Examples for OSPF MIB Support of RFC 1850 and Latest Extensions

- Where to Go Next

- Additional References

- Feature Information for OSPF MIB Support of RFC 1850 and Latest Extensions

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF MIB Support of RFC 1850 and Latest Extensions

- OSPF must be configured on the router.

- Simple Network Management Protocol (SNMP) must be enabled on the router before notifications (traps) can be configured or before SNMP GET operations can be performed.

Restrictions for OSPF MIB Support of RFC 1850 and Latest Extensions

For routers that are running Cisco IOS Release 12.0(26)S, 12.2(25)S, 12.2(27)SBC, 12.2(31)SB2 and later releases, the OSPF MIB and CISCO OSPF MIB will be supported only for the first OSPF process (except for MIB objects that are related to virtual links and sham links, and in cases where support for multiple topologies is provided). SNMP traps will be generated for OSPF events that are related to any of the OSPF processes. There is no workaround for this situation.

Information About OSPF MIB Support of RFC 1850 and Latest Extensions

The following sections contain information about MIB objects standardized as part of RFC 1850 and defined in OSPF-MIB and OSPF-TRAP-MIB. In addition, extensions to RFC 1850 objects are described as defined in the two Cisco private MIBs, CISCO-OSPF-MIB and CISCO-OSPF-TRAP-MIB.

- OSPF MIB Changes to Support RFC 1850

- Benefits of the OSPF MIB

OSPF MIB Changes to Support RFC 1850

- OSPF MIB

- OSPF TRAP MIB

- CISCO OSPF MIB

- CISCO OSPF TRAP MIB

OSPF MIB

This section describes the new MIB objects that are provided by RFC 1850 definitions. These OSPF MIB definitions provide additional capacity that is not provided by the standard OSPF MIB that supported the previous RFC 1253. To see a complete set of OSPF MIB objects, see the OSPF-MIB file.

The table below shows the new OSPF-MIB objects that are provided by RFC 1850 definitions. The objects are listed in the order in which they appear within the OSPF-MIB file, per the tables that describe them.

New OSPF-MIB Objects

OSPF-MIB Table

New MIB Objects

OspfAreaEntry table

- OspfAreaSummary

- OspfAreaStatus

OspfStubAreaEntry

- OspfStubMetricType

OspfAreaRangeEntry

- OspfAreaRangeEffect

OspfHostEntry

- OspfHostAreaID

OspfIfEntry

- OspfIfStatus

- OspfIfMulticastForwarding

- OspfIfDemand

- OspfIfAuthType

OspfVirtIfEntry

- OspfVirtIfAuthType

OspfNbrEntry

- OspfNbmaNbrPermanence

- OspfNbrHelloSuppressed

OspfVirtNbrEntry

- OspfVirtNbrHelloSuppressed

OspfExtLsdbEntry

- OspfExtLsdbType

- OspfExtLsdbLsid

- OspfExtLsdbRouterId

- OspfExtLsdbSequence

- OspfExtLsdbAge

- OspfExtLsdbChecksum

- OspfExtLsdbAdvertisement

OspfAreaAggregateEntry

- OspfAreaAggregateAreaID

- OspfAreaAggregateLsdbType

- OspfAreaAggregateNet

- OspfAreaAggregateMask

- OspfAreaAggregateStatusospfSetTrap

- OspfAreaAggregateEffect

OSPF TRAP MIB

This section describes scalar objects and MIB objects that are provided to support FRC 1850.

The following scalar objects are added to OSPF-TRAP-MIB and are listed in the order in which they appear in the OSPF-TRAP-MIB file:

- OspfExtLsdbLimit

- OspfMulticastExtensions

- OspfExitOverflowInterval

- OspfDemandExtensions

The ospfSetTrap control MIB object contains the OSPF trap MIB objects that enable and disable OSPF traps in the IOS CLI. These OSPF trap MIB objects are provided by the RFC 1850 standard OSPF MIB. To learn how to enable and disable the OSPF traps, see the How to Enable OSPF MIB Support of RFC 1850 and Latest Extensions.

The table below shows the OSPF trap MIB objects, listed in the order in which they appear within the OSPF-TRAP-MIB file.

New OSPF-TRAP-MIB Objects

OSPF Control MIB Object

Trap MIB Objects

ospfSetTrap

- ospfIfStateChange

- ospfVirtIfStateChange

- ospfNbrStateChange

- ospfVirtNbrState

- ospfIfConfigError

- ospfVirtIfConfigError

- ospfIfAuthFailure

- ospfVirtIfAuthFailure

- ospfIfRxBadPacket

- ospfVirtIfRxBadPacket

- ospfTxRetransmit

- ospfVirtIfTxRetransmit

- ospfOriginateLsa

- ospfMaxAgeLsa

CISCO OSPF MIB

This section describes scalar and Cisco-specific OSPF MIB objects that are provided as extensions to support the RFC 1850 OSPF MIB definitions, to provide capability that the standard MIB cannot provide.

The following scalar objects are added to CISCO-OSPF-MIB:

- cospfRFC1583Compatibility

- cospfOpaqueLsaSupport

- cospfOpaqueASLsaCount

- cospfOpaqueASLsaCksumSum

For each of the following table entries, the new Cisco-specific MIB objects that are provided as extensions to support the RFC 1850 OSPF MIB definitions are listed. To see the complete set of objects for the Cisco-specific OSPF MIB, refer to the CISCO-OSPF-MIB file.

The table below shows the new CISCO-OSPF-MIB objects that are provided by RFC 1850 definitions. The objects are listed in the order in which they appear within the CISCO-OSPF-MIB file, per the tables that describe them.

New CISCO-OSPF-MIB Objects

CISCO-OSPF-MIB Table

New MIB Objects

cospfAreaEntry

- cospfOpaqueAreaLsaCount

- cospfOpaqueAreaLsaCksumSum

- cospfAreaNssaTranslatorRole

- cospfAreaNssaTranslatorState

- cospfAreaNssaTranslatorEvents

cospfLsdbEntry

- cospfLsdbType

- cospfLsdbSequence

- cospfLsdbAge

- cospfLsdbChecksum

- cospfLsdbAdvertisement

cospfIfEntry

- cospfIfLsaCount

- cospfIfLsaCksumSum

cospfVirtIfEntry

- cospfVirtIfLsaCount

- cospfVirtIfLsaCksumSum

cospfLocalLsdbEntry

- cospfLocalLsdbIpAddress

- cospfLocalLsdbAddressLessIf

- cospfLocalLsdbType

- cospfLocalLsdbLsid

- cospfLocalLsdbRouterId

- cospfLocalLsdbSequence

- cospfLocalLsdbAge

- cospfLocalLsdbChecksum

- cospfLocalLsdbAdvertisement

cospfVirtLocalLsdbEntry

- cospfVirtLocalLsdbTransitArea

- cospfVirtLocalLsdbNeighbor

- cospfVirtLocalLsdbType

- cospfVirtLocalLsdbLsid

- cospfVirtLocalLsdbRouterId

- cospfVirtLocalLsdbSequence

- cospfVirtLocalLsdbAge

- cospfVirtLocalLsdbChecksum

- cospfVirtLocalLsdbAdvertisement

CISCO OSPF TRAP MIB

The cospfSetTrapMIB object represents trap events in CISCO-OSPF-TRAP-MIB. This is a bit map, where the first bit represents the first trap. The following MIB objects are TRAP events that have been added to support RFC 1850. To see a complete set of Cisco OSPF Trap MIB objects, see the CISCO-OSPF-TRAP-MIB file.

The table below shows the trap events described within the cospfSetTrap MIB object in the CISCO-OSPF-TRAP-MIB:

CISCO-OSPF Trap Events

CISCO-OSPF-TRAP-MIB Trap Events

Trap Event Description

cospfIfConfigError

This trap is generated for mismatched MTU parameter errors that occur when nonvirtual OSPF neighbors are forming adjacencies.

cospfVirtIfConfigError

This trapis generated for mismatched MTU parameter errors when virtual OSPF neighbors are forming adjacencies.

cospfTxRetransmit

This trapis generated in the case of opaque LSAs when packets are sent by a nonvirtual interface. An opaque link-state advertisement (LSA) is used in MPLS traffic engineering to distribute attributes such as capacity and topology of links in a network. The scope of this LSA can be confined to the local network (Type 9, Link-Local), OSPF area (Type 20, Area-Local), or autonomous system (Type 11, AS scope). The information in an opaque LSA can be used by an external application across the OSPF network.

cospfVirtIfTxRetransmit

This trapis generated in the case of opaque LSAs when packets are sent by a virtual interface.

cospfOriginateLsa

This trapis generated when a new opaque LSA is originated by the router when a topology change has occurred.

cospfMaxAgeLsa

The trapis generated in the case of opaque LSAs.

cospfNssaTranslatorStatusChange

The trap is generated if there is a change in the ability of a router to translate OSPF type-7 LSAs into OSPF type-5 LSAs.

For information about how to enable OSPF MIB traps, see the How to Enable OSPF MIB Support of RFC 1850 and Latest Extensions.

Benefits of the OSPF MIB

The OSPF MIBs (OSPF-MIB and OSPF-TRAP-MIB) and Cisco private OSPF MIBs (CISCO-OSPF-MIB and CISCO-OSPF-TRAP-MIB) allow network managers to more effectively monitor the OSPF routing protocol through the addition of new table objects and trap notification objects that previously were not supported by the RFC 1253 OSPF MIB.

New CLI commands have been added to enable SNMP notifications for OSPF MIB support objects, Cisco-specific errors, retransmission and state-change traps. The SNMP notifications are provided for errors and other significant event information for the OSPF network.

How to Enable OSPF MIB Support of RFC 1850 and Latest Extensions

- Enabling OSPF MIB Support

- Enabling Specific OSPF Traps

- Verifying OSPF MIB Traps on the Router

Enabling OSPF MIB Support

Before You Begin

Before the OSPF MIB Support of RFC 1850 and Latest Extensions feature can be used, the SNMP server for the router must be configured.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    snmp-server community string1 ro

4.    snmp-server community string2 rw

5.    snmp-server host {hostname | ip-address} [vrf vrf-name] [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] community-string [udp-port port] [notification-type]

6.    snmp-server enable traps ospf

7.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

snmp-server community string1 ro

Example:

Router(config)# snmp-server community public ro

Enables read access to all objects in the MIB, but does not allow access to the community strings.

Step 4

snmp-server community string2 rw

Example:

Router(config)# snmp-server community private rw

Enables read and write access to all objects in the MIB, but does not allow access to the community strings.

Step 5

snmp-server host {hostname | ip-address} [vrf vrf-name] [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] community-string [udp-port port] [notification-type]

Example:

Router(config)# snmp-server host 172.20.2.162 version 2c public ospf

Specifies a recipient (target host) for SNMP notification operations.

- If no notification-type is specified, all enabled notifications (traps or informs) will be sent to the specified host.

- If you want to send only the OSPF notifications to the specified host, you can use the optional ospfkeyword as one of the notification-types. (See the example.) Entering the ospf keyword enables the ospfSetTrap trap control MIB object.

Step 6

snmp-server enable traps ospf

Example:

Router(config)# snmp-server enable traps ospf

Enables all SNMP notifications defined in the OSPF MIBs.

Note:
This step is required only if you wish to enable all OSPF traps. When you enter the no snmp-server enable traps ospf command, all OSPF traps will be disabled.

Step 7

end

Example:

Router(config)# end

Ends your configuration session and exits global configuration mode.

- What to Do Next

What to Do Next

If you did not want to enable all OSPF traps, follow the steps in the following section to selectively enable one or more type of OSPF trap:

Enabling Specific OSPF Traps

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    snmp-server enable traps ospf cisco-specific errors [config-error] [virt-config-error]

4.    snmp-server enable traps ospf cisco-specific retransmit [packets] [virt-packets]

5.    snmp-server enable traps ospf cisco-specific state-change [nssa-trans-change] [shamlink-state-change]

6.    snmp-server enable traps ospf cisco-specific lsa [lsa-maxage] [lsa-originate]

7.    snmp-server enable traps ospf errors [authentication-failure] [bad-packet] [config-error] [virt-authentication-failure] [virt-config-error]

8.    snmp-server enable traps ospf lsa [lsa-maxage] [lsa-originate]

9.    snmp-server enable traps ospf rate-limit seconds trap-number

10.    snmp-server enable traps ospf retransmit [packets] [virt-packets]

11.    snmp-server enable traps ospf state-change [if-state-change] [neighbor-state-change] [virtif-state-change] [virtneighbor-state-change]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

snmp-server enable traps ospf cisco-specific errors [config-error] [virt-config-error]

Example:

Router(config)# snmp-server enable traps ospf cisco-specific errors config-error

Enables SNMP notifications for Cisco-specific OSPF configuration mismatch errors.

- Entering the snmp-server enable traps ospf cisco-specific errors command with the optional virt-config-error keyword enables only the SNMP notifications for configuration mismatch errors on virtual interfaces.

Step 4

snmp-server enable traps ospf cisco-specific retransmit [packets] [virt-packets]

Example:

Router(config)# snmp-server enable traps ospf cisco-specific retransmit packets virt-packets

Enables error traps for Cisco-specific OSPF errors that involve re-sent packets.

- Entering the snmp-server enable traps ospf cisco-specific retransmit command with the optional virt-packetskeyword enables only the SNMP notifications for packets that are re-sent on virtual interfaces.

Step 5

snmp-server enable traps ospf cisco-specific state-change [nssa-trans-change] [shamlink-state-change]

Example:

Router(config)# snmp-server enable traps ospf cisco-specific state-change

Enables all error traps for Cisco-specific OSPF transition state changes.

Step 6

snmp-server enable traps ospf cisco-specific lsa [lsa-maxage] [lsa-originate]

Example:

Router(config)# snmp-server enable traps ospf cisco-specific lsa

Enables error traps for opaque LSAs.

Step 7

snmp-server enable traps ospf errors [authentication-failure] [bad-packet] [config-error] [virt-authentication-failure] [virt-config-error]

Example:

Router(config)# snmp-server enable traps ospf errors virt-config-error

Enables error traps for OSPF configuration errors.

- Entering the snmp-server enable traps ospf errors command with the optional virt-config-errorkeyword enables only the SNMP notifications for OSPF configuration errors on virtual interfaces.

Step 8

snmp-server enable traps ospf lsa [lsa-maxage] [lsa-originate]

Example:

Router(config)# snmp-server enable traps ospf lsa

Enables error traps for OSPF LSA errors.

Step 9

snmp-server enable traps ospf rate-limit seconds trap-number

Example:

Router(config)# snmp-server enable traps ospf rate-limit 20 20

Sets the rate limit for how many SNMP OSPF notifications are sent in each OSPF SNMP notification rate-limit window.

Step 10

snmp-server enable traps ospf retransmit [packets] [virt-packets]

Example:

Router(config)# snmp-server enable traps ospf retransmit

Enables SNMP OSPF notifications for re-sent packets.

Step 11

snmp-server enable traps ospf state-change [if-state-change] [neighbor-state-change] [virtif-state-change] [virtneighbor-state-change]

Example:

Router(config)# snmp-server enable traps ospf state-change

Enables SNMP OSPF notifications for OSPF transition state changes.

Verifying OSPF MIB Traps on the Router

SUMMARY STEPS

1.    enable

2.    show running-config [options]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show running-config [options]

Example:

Router# show running-config | include traps

Displays the contents of the currently running configuration file and includes information about enabled traps.

- Verifies which traps are enabled.

Configuration Examples for OSPF MIB Support of RFC 1850 and Latest Extensions

- Example Enabling and Verifying OSPF MIB Support Traps

Example Enabling and Verifying OSPF MIB Support Traps

The following example enables all OSPF traps.

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# snmp-server enable traps ospf
Router(config)# end

The show running-config command is entered to verify that the traps are enabled:

Router# show running-config | include traps
snmp-server enable traps ospf

Where to Go Next

For more information about SNMP and SNMP operations, see the "Configuring SNMP Support" chapter of the Cisco IOS Configuration Fundamentals and Network Management Configuration Guide, Release 12.2.

Additional References

The following sections provide references related to the OSPF MIB Support of RFC 1850 and Latest Extensions feature.

Related Documents

Related Topic

Document Title

SNMP commands

Cisco IOS Configuration Fundamentals and Network Management Command Reference

Standards

Standard

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIB

MIB

MIBs Link

- CISCO-OSPF-MIB

- CISCO-OSPF-TRAP-MIB

- OSPF-MIB

- OSPF-TRAP-MIB

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFC

RFC

Title

RFC 1850

OSPF MIB Support

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF MIB Support of RFC 1850 and Latest Extensions

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF MIB Support of RFC 1850 and Latest Extensions

Feature Name

Releases

Feature Information

OSPF MIB Support of RFC 1850 and Latest Extensions

12.0(26)S 12.3(4)T 12.2(25)S 12.2(27)SBC 12.2(31)SB2

OSPF MIB Support of RFC 1850 and Latest Extensions feature introduces the capability for Simple Network Management Protocol (SNMP) monitoring on the Open Shortest Path First (OSPF) routing protocol. Users have an improved ability to constantly monitor the changing state of an OSPF network by use of MIB objects to gather information relating to protocol parameters and trap notification objects that can signal the occurrence of significant network events such as transition state changes. The protocol information collected by the OSPF MIB objects and trap objects can be used to derive statistics that will help monitor and improve overall network performance.

Chapter 34. SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields

This document describes the configuration command that allows you to use either the current interface number or the SNMP MIB-II interface index (ifIndex) value for the interface ID in OSPFv2 and OSPFv3 data fields. The advantage to using the SNMP MIB-II ifIndex value is that this number corresponds to the number that the user will see reported by SNMP.

- Finding Feature Information

- Prerequisites for Interface ID in Data Fields

- Information About Interface ID in Data Fields

- How to Configure the Interface ID in Data Fields

- Configuration Examples for the Interface ID in Data Fields

- Additional References

- Feature Information for SNMP ifIndex Value for Interface ID in Data Fields

- Glossary

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for Interface ID in Data Fields

OSPF must be configured on the router.

Information About Interface ID in Data Fields

Before choosing to switch from the current interface numbers to the SNMP MIB-II interface ID numbers, you should understand the following concepts:

- Benefits of Choosing to Identify Interfaces by the SNMP MIB-II ifIndex Value

- How OSPFv2 and OSPFv3 Use the SNMP MIB-II ifIndex Value

Benefits of Choosing to Identify Interfaces by the SNMP MIB-II ifIndex Value

If you use Simple Network Management Protocol (SNMP) for your OSPF network, configuring the OSPF: SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields feature can be beneficial for the following reasons:

- Using the SNMP MIB-II ifIndex (interface index) identification numbers to identify OSPF interfaces makes it easier for network administrators to identify interfaces because the numbers will correspond to the numbers that they will see reported by SNMP.

- When examining link-state advertisements (LSAs), the value used in fields that have the interface ID will be the same as the value that is reported by SNMP.

- When looking at the output of the show ipv6 ospf interface command, the interface ID number will have the same value that is reported by SNMP.

- Using the SNMP MIB-II IfIndex is also suggested, but not required, by the OSPF RFC 2328 for OSPFv2 and the RFC 2740 for OSPFv3.

How OSPFv2 and OSPFv3 Use the SNMP MIB-II ifIndex Value

The user chooses for OSPF interfaces to use the SNMP MIB-II ifIndex number by entering the interface-id snmp-if-index command for a specific OSPF process. If an interface under the specific OSPF process does not have an SNMP ifIndex number, OSPF will not be enabled on that interface.

For OSPFv2, the ifIndex number is used for the Link Data field in the Router LSA for unnumbered point-to-point interfaces and sham links. When the interface-id snmp-if-index command is entered, the affected LSAs will immediately be reoriginated.

For OSPFv3, the ifIndex number is used for the interface ID in router LSAs, as the LSID in Network and Link LSAs, and also as the interface ID in Hello packets. Intra-Area-Prefix LSAs that reference Network LSAs have the network LSAs LSID in the Referenced LSID field, so they will also be updated when the interface-id snmp-if-index command is entered. The old Network, Link and Intra-Area-Prefix LSAs that are associated with a Network LSA will be flushed.

For both OSPFv2 and OSPFv3, adjacencies are not flapped, except for affected OSPFv3 demand circuits (including virtual links) with full adjacencies.

For both OSPFv2 and OSPFv3, if an interface does not have an SNMP ifIndex number and an interface ID is needed (for OSPFv2 this applies only to unnumbered interfaces and sham links), an error message will be generated and the interface will be disabled. The interface will be reenabled if the no interface-id snmp-if-index command is entered.

How to Configure the Interface ID in Data Fields

- Using SNMP MIB-II ifIndex Numbers

Using SNMP MIB-II ifIndex Numbers

Follow the steps in this task to configure OSPF interfaces to use the SNMP MIB-II ifIndex numbers. These steps work for both OSPFv2 and OSPFv3. All OSPF interfaces must use the SNMP MIB-II ifIndex numbers or the interfaces will not be enabled for OSPF. Therefore, repeat the steps within this task for each OSPF process for which you want the interfaces to use the SNMP MIB-II ifIndex numbers.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    Do one of the following:

- router ospf process-id [vrf vpn-name]

- ipv6 router ospf process-id

4.    interface-id snmp-if-index

5.    end

6.    show snmp mib ifmib ifindex [interface-type] [slot /][port-adapter /][port]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

Do one of the following:

- router ospf process-id [vrf vpn-name]

- ipv6 router ospf process-id

Example:

Device(config)# router ospf 4

Example:

Device(config)# ipv6 router ospf 4

Configures an OSPFv2 routing process and enters router configuration mode.

Configures an OSPFv3 routing process and enters router configuration mode.

Step 4

interface-id snmp-if-index

Example:

Device(config-router)# interface-id snmp-if-index

Configures OSPF interfaces with the SNMP interface index identification numbers (ifIndex values).

Step 5

end

Example:

Device(config-router)# end

Returns to privileged EXEC mode.

Step 6

show snmp mib ifmib ifindex [interface-type] [slot /][port-adapter /][port]

Example:

Device# show snmp mib ifmib ifindex Ethernet 0/1

Displays SNMP interface index identification numbers (ifIndex values) for all the system interfaces or the specified system interface.

Configuration Examples for the Interface ID in Data Fields

- Configuring the SNMP ifIndex Value for Interface ID for OSPFv2 Example

- Configuring the SNMP ifIndex Value for Interface ID for OSPFv3 Example

Configuring the SNMP ifIndex Value for Interface ID for OSPFv2 Example

The following example configures the OSPF interfaces to use the SNMP ifIndex values for the interfaces IDs. The show snmp mib ifmib ifindex command confirms that the SNMP MIB-II ifIndex values are used for the Interface ID values in the OSPFv2 data fields.

Device# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Device(config)# router ospf 1
Device(config-router)# interface-id snmp-if-index
Device(config-router)# ^Z
Device# show ip ospf 1 1 data router self
OSPF Router with ID (172.16.0.1) (Process ID 1)
Router Link States (Area 1)
LS age: 6
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 172.16.0.1
Advertising Router: 172.16.0.1
LS Seq Number: 80000007
Checksum: 0x63AF
Length: 48
Area Border Router
Number of Links: 2
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 172.17.0.1
(Link Data) Router Interface address: 0.0.0.53
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 192.168.0.11
(Link Data) Network Mask: 255.255.255.255
Number of TOS metrics: 0
TOS 0 Metrics: 1
Device# show snmp mib ifmib ifindex s13/0
Serial13/0: Ifindex = 53

Configuring the SNMP ifIndex Value for Interface ID for OSPFv3 Example

The following example configures the OSPFv3 interfaces to use the SNMP ifIndex values for the interface IDs.

Device# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Device(config)# ipv6 router ospf 1
Device(config-router)# interface-id snmp-if-index

The output from the show snmp mib ifmib ifindex command confirms that the SNMP MIB-II ifIndex values are being used for the Interface ID values in the OSPFv3 data fields.

Device# show snmp mib ifmib ifindex Ethernet1/0
Ethernet1/0: Ifindex = 5
Device#
Device# show ipv6 ospf int
OSPF_VL0 is up, line protocol is up
Interface ID 71
Area 0, Process ID 1, Instance ID 0, Router ID 172.16.0.1
Network Type VIRTUAL_LINK, Cost: 10
Configured as demand circuit.
Run as demand circuit.
DoNotAge LSA allowed.
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Index 1/2/3, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.0.0.1  (Hello suppressed)
Suppress hello for 1 neighbor(s)
Ethernet2/0 is up, line protocol is up
Link Local Address FE80::A8BB:CCFF:FE00:6F02, Interface ID 10
Area 0, Process ID 1, Instance ID 0, Router ID 172.16.0.1
Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.16.0.1, local address FE80::A8BB:CCFF:FE00:6F02
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:06
Index 1/1/2, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
Ethernet1/0 is up, line protocol is up
Link Local Address FE80::A8BB:CCFF:FE00:6F01, Interface ID 6
Area 1, Process ID 1, Instance ID 2, Router ID 172.16.0.1
Network Type BROADCAST, Cost: 10
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 172.16.0.1, local address FE80::A8BB:CCFF:FE00:6F01
Backup Designated router (ID) 10.0.0.1, local address FE80::A8BB:CCFF:FE00:6E01
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:06
Index 1/1/1, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 2
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.0.0.1  (Backup Designated Router)
Suppress hello for 0 neighbor(s)
Device#
Device# show ipv6 ospf data net adv 172.16.0.1
OSPFv3 Router with ID (172.16.0.1) (Process ID 1)
Net Link States (Area 1)
LS age: 144
Options: (V6-Bit E-Bit R-bit DC-Bit)
LS Type: Network Links
Link State ID: 6 (Interface ID of Designated Router)
Advertising Router: 172.16.0.1
LS Seq Number: 80000001
Checksum: 0x1FC0
Length: 32
Attached Router: 172.16.0.1
Attached Router: 10.0.0.1
Device# show ipv6 ospf data prefix adv 172.16.0.1
OSPFv3 Router with ID (172.16.0.1) (Process ID 1)
Intra Area Prefix Link States (Area 0)
Routing Bit Set on this LSA
LS age: 196
LS Type: Intra-Area-Prefix-LSA
Link State ID: 0
Advertising Router: 172.16.0.1
LS Seq Number: 80000001
Checksum: 0x6F11
Length: 44
Referenced LSA Type: 2001
Referenced Link State ID: 0
Referenced Advertising Router: 172.16.0.1
Number of Prefixes: 1
Prefix Address: 2002:0:2::
Prefix Length: 64, Options: None, Metric: 10
Intra Area Prefix Link States (Area 1)
Routing Bit Set on this LSA
LS age: 161
LS Type: Intra-Area-Prefix-LSA
Link State ID: 0
Advertising Router: 172.16.0.1
LS Seq Number: 80000001
Checksum: 0xB6E7
Length: 52
Referenced LSA Type: 2001
Referenced Link State ID: 0
Referenced Advertising Router: 172.16.0.1
Number of Prefixes: 1
Prefix Address: 2002:0:2:0:A8BB:CCFF:FE00:6F02
Prefix Length: 128, Options: LA , Metric: 0
Routing Bit Set on this LSA
LS age: 151
LS Type: Intra-Area-Prefix-LSA
Link State ID: 1006
Advertising Router: 172.16.0.1
LS Seq Number: 80000001
Checksum: 0x6E24
Length: 44
Referenced LSA Type: 2002
Referenced Link State ID: 6
Referenced Advertising Router: 172.16.0.1
Number of Prefixes: 1
Prefix Address: 2002:0:1::
Prefix Length: 64, Options: None, Metric: 0
Device#
Device# show ipv6 ospf data router
OSPFv3 Router with ID (10.0.0.1) (Process ID 1)
Router Link States (Area 0)
Routing Bit Set on this LSA
LS age: 5 (DoNotAge)
Options: (V6-Bit E-Bit R-bit DC-Bit)
LS Type: Router Links
Link State ID: 0
Advertising Router: 10.0.0.1
LS Seq Number: 80000004
Checksum: 0xEE5C
Length: 40
Area Border Router
Number of Links: 1
Link connected to: a Virtual Link
Link Metric: 10
Local Interface ID: 70
Neighbor Interface ID: 71
Neighbor Router ID: 172.16.0.1
LS age: 162
Options: (V6-Bit E-Bit R-bit DC-Bit)
LS Type: Router Links
Link State ID: 0
Advertising Router: 172.16.0.1
LS Seq Number: 80000004
Checksum: 0xCE7C
Length: 40
Area Border Router
Number of Links: 1
Link connected to: a Virtual Link
Link Metric: 10
Local Interface ID: 71
Neighbor Interface ID: 70
Neighbor Router ID: 10.0.0.1
Router Link States (Area 1)
Routing Bit Set on this LSA
LS age: 176
Options: (V6-Bit E-Bit R-bit DC-Bit)
LS Type: Router Links
Link State ID: 0
Advertising Router: 10.0.0.1
LS Seq Number: 80000003
Checksum: 0xC807
Length: 40
Area Border Router
Number of Links: 1
Link connected to: a Transit Network
Link Metric: 10
Local Interface ID: 6
Neighbor (DR) Interface ID: 6
Neighbor (DR) Router ID: 172.16.0.1
LS age: 175
Options: (V6-Bit E-Bit R-bit DC-Bit)
LS Type: Router Links
Link State ID: 0
Advertising Router: 172.16.0.1
LS Seq Number: 80000004
Checksum: 0xBD10
Length: 40
Area Border Router
Number of Links: 1
Link connected to: a Transit Network
Link Metric: 10
Local Interface ID: 6
Neighbor (DR) Interface ID: 6
Neighbor (DR) Router ID: 172.16.0.1
Device#
Device# show ipv6 ospf data link adv 172.16.0.1
OSPFv3 Router with ID (172.16.0.1) (Process ID 1)
Link (Type-8) Link States (Area 0)
LS age: 245
Options: (V6-Bit E-Bit R-bit DC-Bit)
LS Type: Link-LSA (Interface: Ethernet2/0)
Link State ID: 10 (Interface ID)
Advertising Router: 172.16.0.1
LS Seq Number: 80000002
Checksum: 0xA0CB
Length: 56
Router Priority: 1
Link Local Address: FE80::A8BB:CCFF:FE00:6F02
Number of Prefixes: 1
Prefix Address: 2002:0:2::
Prefix Length: 64, Options: None
Link (Type-8) Link States (Area 1)
LS age: 250
Options: (V6-Bit E-Bit R-bit DC-Bit)
LS Type: Link-LSA (Interface: Ethernet1/0)
Link State ID: 6 (Interface ID)
Advertising Router: 172.16.0.1
LS Seq Number: 80000001
Checksum: 0x4F94
Length: 44
Router Priority: 1
Link Local Address: FE80::A8BB:CCFF:FE00:6F01
Number of Prefixes: 0

Additional References

The following sections provide references related to the OSPF: SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields feature.

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OPSF Command Reference

OSPF configuration

"Configuring OSPF"

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

RFC 2328

OSPF Version 2

RFC 2740

OSPF Version 3

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for SNMP ifIndex Value for Interface ID in Data Fields

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF: SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields

Feature Name

Releases

Feature Information

OSPF: SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields

12.4(6)T 12.2(31)SB2 12.2(33)SRB 15.0(1)SY

This document describes the configuration command that allows you the choice to use either the current interface number or the SNMP ifIndex value for the interface ID in OSPFv2 and OSPFv3 data fields. The advantage to using the SNMP MIB-II ifIndex value is that this number corresponds to the number that the user will see reported by SNMP.

Glossary

SNMP --Simple Network Management Protocol (SNMP) is an application layer protocol that facilitates the exchange of management information between network devices. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite.

Note

See Internetworking Terms and Acronyms for terms not included in this glossary.

Chapter 35. OSPFv3 Graceful Restart

The graceful restart feature in Open Shortest Path First version 3 (OSPFv3) allows nonstop data forwarding along routes that are already known while the OSPFv3 routing protocol information is being restored.

- Finding Feature Information

- Information About OSPFv3 Graceful Restart

- How to Enable OSPFv3 Graceful Restart

- Configuration Examples for OSPFv3 Graceful Restart

- Additional References

- Feature Information for OSPFv3 Graceful Restart

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Information About OSPFv3 Graceful Restart

- OSPFv3 Graceful Restart

OSPFv3 Graceful Restart

The graceful restart feature in OSPFv3 allows nonstop data forwarding along routes that are already known while the OSPFv3 routing protocol information is being restored. A device can participate in graceful restart either in restart mode (such as in a graceful-restart-capable device) or in helper mode (such as in a graceful-restart-aware device).

To perform the graceful restart function, a device must be in high availability (HA) stateful switchover (SSO) mode (that is, dual Route Processor (RP)). A device capable of graceful restart will perform the graceful restart function when the following failures occur:

- A RP failure that results in switchover to standby RP

- A planned RP switchover to standby RP

The graceful restart feature requires that neighboring devices be graceful-restart aware.

For further information about SSO and nonstop forwarding (NSF), see the Stateful Switchover and Cisco Nonstop Forwarding documents.

How to Enable OSPFv3 Graceful Restart

- Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Device

- Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Device

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Device

This task can be performed for the OSPFv3 Graceful Restart feature in both IPv6 and IPv4.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    graceful-restart [restart-interval interval]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

graceful-restart [restart-interval interval]

Example:

Device(config-rtr)# graceful-restart

Enables the OSPFv3 graceful restart feature on a graceful-restart-capable device.

- Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Device

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Capable Device

The task can be performed in releases prior to Cisco IOS Release 15.1(3)S and 15.2(1)T.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 router ospf process-id

4.    graceful-restart [restart-interval interval]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

graceful-restart [restart-interval interval]

Example:

Device(config-rtr)# graceful-restart

Enables the OSPFv3 graceful restart feature on a graceful-restart-capable device.

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Device

This task can be performed for the OSPFv3 Graceful Restart feature in both IPv6 and IPv4.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    graceful-restart helper {disable | strict-lsa-checking}

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

graceful-restart helper {disable | strict-lsa-checking}

Example:

Device(config-rtr)# graceful-restart helper strict-lsa-checking

Enables the OSPFv3 graceful restart feature on a graceful-restart-aware device.

- Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Device

Enabling OSPFv3 Graceful Restart on a Graceful-Restart-Aware Device

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 router ospf process-id

4.    graceful-restart helper {disable | strict-lsa-checking}

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

graceful-restart helper {disable | strict-lsa-checking}

Example:

Device(config-rtr)# graceful-restart helper strict-lsa-checking

Enables the OSPFv3 graceful restart feature on a graceful-restart-aware device.

Configuration Examples for OSPFv3 Graceful Restart

- Example: Enabling OSPFv3 Graceful Restart

Example: Enabling OSPFv3 Graceful Restart

Router# show ipv6 ospf graceful-restart
Routing Process "ospf 1"
Graceful Restart enabled
restart-interval limit: 120 sec, last restart 00:00:15 ago (took 36 secs)
Graceful Restart helper support enabled
Router status : Active
Router is running in SSO mode
OSPF restart state : NO_RESTART
Router ID 10.1.1.1, checkpoint Router ID 10.0.0.0

The following example shows OSPFv3 information with graceful-restart helper support enabled on a graceful-restart-aware router.

Router# show ospfv3
Routing Process "ospfv3 1" with ID 10.0.0.1
Supports IPv6 Address Family
Event-log enabled, Maximum number of events: 1000, Mode: cyclic
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 0. Checksum Sum 0x000000
Number of areas in this router is 0. 0 normal 0 stub 0 nssa
Graceful restart helper support enabled
Reference bandwidth unit is 100 mbps
Relay willingness value is 128
Pushback timer value is 2000 msecs
Relay acknowledgement timer value is 1000 msecs
LSA cache Disabled : current count 0, maximum 1000
ACK cache Disabled : current count 0, maximum 1000
Selective Peering is not enabled
Hello requests and responses will be sent multicast

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Stateful switchover and Cisco nonstop forwarding

High Availability Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

OSPFv3 Graceful Restart

“OSPF RFC 3623 Graceful Restart Helper Mode” module

OSPFv3 Graceful Restart

“Configuring OSPF ” module

OSPFv3 Graceful Restart

“NSF-OSPF RFC 3623 OSPF Graceful Restart ” module

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 Graceful Restart

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 Graceful Restart

Feature Name

Releases

Feature Information

OSPFv3 Graceful Restart

12.2(58)SE

12.2(33)SRE

15.0(1)M

15.0(1)SY

The graceful restart feature in OSPFv3 allows nonstop data forwarding along routes that are already known while the OSPFv3 routing protocol information is being restored.

The following commands were introduced or modified: graceful-restart, graceful-restart helper, ipv6 router ospf, router ospfv3, show ipv6 ospf graceful-restart, show ospfv3 graceful-restart.

Chapter 36. OSPF RFC 3623 Graceful Restart Helper Mode

This document focuses on Nonstop Forwarding (NSF) helper mode for OSPFv2 in Cisco IOS software, using IETF standardized graceful restart helper mode functionality as described in RFC 3623, Graceful OSPF Restart. Graceful restart helper mode functionality, which is enabled by default, is useful for multiplatform network environments where helper mode routers on some platforms can assist restarting routers on mixed platforms that support OSPF graceful restart mode as well as helper mode.

- Finding Feature Information

- Prerequisites for OSPF RFC 3623 Graceful Restart Helper Mode

- Restrictions for OSPF RFC 3623 Graceful Restart Helper Mode

- Information About OSPF RFC 3623 Graceful Restart Helper Mode

- How to Use OSPF RFC 3623 Graceful Restart Helper Mode

- Configuration Examples for OSPF RFC 3623 Graceful Restart Helper Mode

- Additional References

- Feature Information for OSPF RFC 3623 Graceful Restart Helper Mode

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPF RFC 3623 Graceful Restart Helper Mode

- OSPF must be configured on the router.

Restrictions for OSPF RFC 3623 Graceful Restart Helper Mode

- IETF Graceful Restart is not supported over sham-links.

Information About OSPF RFC 3623 Graceful Restart Helper Mode

- Cisco NSF Routing and Forwarding Operation

- Cisco Express Forwarding for NSF

- OSPF Graceful Restart Helper Mode Functionality per RFC 3623

Cisco NSF Routing and Forwarding Operation

Prior to RFC 3623 Cisco implemented the Cisco proprietary NSF referred to as Cisco NSF. Users can configure either Cisco or RFC 3623 IETF NSF, depending on which versions are supported by the Cisco IOS software version running on the network. If the software version supports both types of NSF, you need to configure all routers with the same type of NSF.

Cisco NSF is supported by the BGP, EIGRP, OSPF, and IS-IS protocols for routing and by Cisco Express Forwarding (CEF) for forwarding. The BGP, EIGRP, OSPF, and IS-IS routing protocols have been enhanced with NSF capability and awareness, which means that routers that run these protocols can detect a switchover and take the necessary actions to continue forwarding network traffic and to recover route information from the neighbor routers.

In this document, a networking device is said to be NSF-aware if it is running NSF-compatible software. A device is said to be NSF-capable if it has been configured to support NSF; therefore, it would rebuild routing information from NSF-aware or NSF-capable neighbors. The NSF router mode of operation common to the Cisco and IETF NSF implementations is as follows:

- Restarting Mode--Also known as IETF NSF-restarting mode or graceful-restarting mode. In this mode, the OSPF router process is performing non-stop forwarding recovery because of an RP switchover; this may result from an RP crash or a software upgrade on the active RP.

- Helper Mode--Also known as IETF NSF-awareness. In this mode, the neighboring router is restarting and helping in the NSF recovery.

For more information about OSPF RFC 3623 Graceful Restart, see Click Here .

Cisco Express Forwarding for NSF

A key element of NSF is packet forwarding. The OSPF protocol depends on CEF to continue forwarding packets during switchover while the routing protocols rebuild the Routing Information Base (RIB) tables. Once OSPF has converged, CEF updates the Forwarding Information Base (FIB) table and removes stale route entries. CEF then updates the line cards with the new FIB information. CEF maintains the FIB and uses the FIB information that was current at the time of a switchover to continue forwarding packets during the switchover. This feature reduces traffic interruption during the switchover.

During normal NSF operation, CEF on the active RP synchronizes its current FIB and adjacency databases with the FIB and adjacency databases on the standby RP. Upon switchover of the active RP, the standby RP initially has FIB and adjacency databases that are mirror images of those that were current on the active RP. For platforms with intelligent line cards, the line cards maintain the current forwarding information over a switchover; for platforms with forwarding engines, CEF keeps the forwarding engine on the standby RP current with changes that are sent to it by CEF on the active RP. In this way, the line cards or forwarding engines can continue forwarding after a switchover as soon as the interfaces and a data path are available.

As the OSPF routing protocol starts to repopulate the RIB on a prefix-by-prefix basis, the updates in turn cause prefix-by-prefix updates that CEF uses to update the FIB and adjacency databases. Existing and new entries receive the new version number, indicating that they have been refreshed. The forwarding information is updated on the line cards or forwarding engines during convergence. The RP signals when the RIB has converged. The software removes all FIB and adjacency entries that have an epoch older than the current switchover epoch. The FIB now represents the newest routing protocol forwarding information.

The OSPF routing protocol runs on only the active RP, and OSPF receives routing updates from OSPF neighbor routers. The OSPF routing protocol does not run on the standby RP. Following a switchover, OSPF requests that the NSF-aware neighbor devices send state information to help rebuild the routing tables.

Note

For NSF operation, OSPF depends on CEF to continue forwarding packets while OSPF rebuilds the routing information.

OSPF Graceful Restart Helper Mode Functionality per RFC 3623

Helper Mode Initiation

When a neighbor router that is on the same network segment as the restarting router receives a grace-LSA from the restarting router, the neighbor enters helper mode as long as the following criteria are met:

- The neighbor must have a full adjacency with the restarting router over the associated network segment.

- There have been no changes to the link-state database since the restarting router began restarting.

- The grace period has not yet expired.

- Local policy allows the neighbor router to act as a helper router.

- The neighbor router must not be in its own graceful restart process.

- Helper mode for this router has not been disabled by the network administrator.

Helper Mode Exit

The helper router stops performing helper mode for its neighbor when one of the following events occur:

- The grace-LSA that was originated by the restarting router is flushed, to signify that the restarting router has exited the graceful restart process successfully.

- The grace period of the grace-LSA expires.

- A change in link-state database contents indicates a network topology change, forcing the termination of the graceful restart process.

For complete information about graceful restart functionality, see RFC 3623 at Click Here .

The OSPF RFC 3623 Graceful Restart Helper Mode feature is enabled by default. Disabling this feature is not recommended because the disabled neighbor will detect the lost adjacency and the graceful restart process will be terminated on the restarting neighbor router.

The strict LSA checking feature allows a helper router to terminate the graceful restart process if it detects a changed LSA that would cause flooding during the graceful restart process. Strict LSA checking is disabled by default. You can enable strict LSA checking when there is a change to an LSA that would be flooded to the restarting router. You can configure strict LSA checking on both NSF-aware and NSF-capable routers; however, it becomes effective only when the router is in helper mode.

How to Use OSPF RFC 3623 Graceful Restart Helper Mode

- Configuring Strict LSA Checking on the Helper Router

Configuring Strict LSA Checking on the Helper Router

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id [vrf vpn-name]

4.    nsf ietf helper disable

5.    nsf ietf helper strict-lsa-checking

6.    end

7.    show ip ospf [process-id]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id [vrf vpn-name]

Example:

Router(config)# router ospf 454

Configures an Open Shortest Path First (OSPF) routing process and enters router configuration mode.

Step 4

nsf ietf helper disable

Example:

Router(config-router)# nsf ietf helper disable

Disables helper mode for IETF NSF.

Step 5

nsf ietf helper strict-lsa-checking

Example:

Router(config-router)# nsf ietf strict-lsa-checking

Enables strict LSA checking on an NSF-aware (helper) router.

Step 6

end

Example:

Router(config-router)# end

Returns to privileged EXEC mode.

Step 7

show ip ospf [process-id]

Example:

Router# show ip ospf 454

Displays general information about OSPF routing processes and whether helper mode or strict LSA checking is enabled for the NSF-aware (helper) router.

Configuration Examples for OSPF RFC 3623 Graceful Restart Helper Mode

- Example Disabling Helper Support for IETF NSF

Example Disabling Helper Support for IETF NSF

The following configuration example disables helper support for OSPF NSF.

Router(config)# router ospf 200
Router(config-router)# nsf ietf helper disable

Additional References

The following sections provide references related to the OSPF RFC 3623 Graceful Restart Helper Mode feature.

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

OSPF configuration

"Configuring OSPF"

Cisco NSF feature in Cisco IOS software.

"Cisco Nonstop Forwarding"

Master list of Cisco IOS commands

Cisco IOS Master Command List, All Releases

OSPFv3 Graceful Restart

‘ OSPFv3 Graceful Restart ’ module

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

RFC 2328

OSPF Version 2

RFC 3623

Graceful OSPF Restart

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF RFC 3623 Graceful Restart Helper Mode

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF RFC 3623 Graceful Restart Helper Mode

Feature Name

Releases

Feature Information

OSPF RFC 3623 Graceful Restart Helper Mode

12.4(6)T

This document focuses on NSF for OSPFv2 in Cisco IOS software, using IETF standardized graceful restart functionality as described in RFC 3623.

The following commands were introduced or modified: nsf cisco helper disable, nsf ietf helper disable, nsf ietf helper strict-lsa-checking.

Chapter 37. OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements

This document describes the Open Shortest Path First (OSPF) mechanism to exclude IP prefixes of connected networks from link-state advertisements (LSAs). When OSPF is deployed in large networks, limiting the number of IP prefixes that are carried in the OSPF LSAs can speed up OSPF convergence.

This feature can also be utilized to enhance the security of an OSPF network by allowing the network administrator to prevent IP routing toward internal nodes.

- Finding Feature Information

- Prerequisites for Excluding Connected IP Prefixes from LSAs

- Information About Excluding Connected IP Prefixes from LSAs

- How to Exclude Connected IP Prefixes from OSPF LSAs

- Configuration Examples for Excluding Connected IP Prefixes from LSAs

- Additional References

- Feature Information for OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements

- Glossary

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for Excluding Connected IP Prefixes from LSAs

Before you can use the mechanism to exclude IP prefixes from LSAs, the OSPF routing protocol must be configured.

Information About Excluding Connected IP Prefixes from LSAs

One way to improve OSPF network convergence is to limit the number of IP prefixes carried in LSAs.

- Previous Methods to Limit the Number of IP Prefixes Carried in LSAs

- Feature Overview

Previous Methods to Limit the Number of IP Prefixes Carried in LSAs

Configuring interfaces as unnumbered limits IP prefixes. However, for network management and the ease of identifying and troubleshooting numbered interfaces, you might want to have numbered interfaces and also want to limit the number of IP advertisements.

Feature Overview

The OSPF mechanism to exclude connected IP prefixes from LSAs allows network administrators to control what IP prefixes are installed into LSAs. This functionality is implemented for router and network LSAs in the following manner:

- For the router LSA, to exclude prefixes, the feature excludes link type 3 (stub link).

- For the network LSA, the OSPF Designated Router (DR) generates LSAs with a special /32 network mask (0xFFFFFFFF).

Note

Previous versions of Cisco IOS software that do not have this feature will install the /32 prefix into the routing table.

Globally Suppressing IP Prefix Advertisements per OSPF Process

You can reduce OSPF convergence time by configuring the OSPF process on a router to prevent the advertisement of all IP prefixes by using the prefix-suppression command in router configuration mode.

Note

Prefixes that are associated with loopbacks, secondary IP addresses, and passive interfaces are excluded because typical network designs require those to remain reachable.

Suppressing IP Prefix Advertisements on a Per-Interface Basis

You can explicitly configure an OSPF interface not to advertise its IP network to its neighbors by using the ip ospf prefix-suppression command in interface configuration mode.

Note

If you have globally suppressed IP prefixes from connected IP networks by configuring the prefix-suppression router configuration command, the interface configuration command takes precedence over the router configuration mode command.

How to Exclude Connected IP Prefixes from OSPF LSAs

This section describes how to configure two alternative methods to suppress IP prefix advertisements. You can suppress IP prefix advertisements per OSPF process or per interface. This section also explains how you can troubleshoot IP prefix suppression.

- Excluding IP Prefixes per OSPF Process

- Excluding IP Prefixes on a Per-Interface Basis

- Troubleshooting IP Prefix Suppression

Excluding IP Prefixes per OSPF Process

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id [vrf vpn-name]

4.    prefix-suppression

5.    end

6.    show ip ospf

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id [vrf vpn-name]

Example:

Device(config)# router ospf 23

Configures an OSPFv2 routing process and enters router configuration mode.

Step 4

prefix-suppression

Example:

Device(config-router)# prefix-suppression

Prevents OSPF from advertising all IP prefixes except prefixes that are associated with loopbacks, secondary IP addresses, and passive interfaces.

Step 5

end

Example:

Device(config-router)# end

Returns to privileged EXEC mode.

Step 6

show ip ospf

Example:

Device# show ip ospf

Displays general information about OSPF routing processes.

Note:
Use this command to verify that IP prefix suppression has been enabled.

Examples

In the following example, output from the show ip ospf command shows that IP prefix advertisement has been suppressed for OSPF process 1.

Device# show ip ospf

Routing Process "ospf 1" with ID 10.0.0.6
Start time: 00:00:04.912, Time elapsed: 00:02:35.184
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
It is an area border router
Router is not originating router-LSAs with maximum metric
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Incremental-SPF disabled
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 2. Checksum Sum 0x0132C8
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 3. 3 normal 0 stub 0 nssa
Number of areas transit capable is 1
External flood list length 0
IETF NSF helper support enabled
Cisco NSF helper support enabled
Prefix-suppression is enabled
.
.
.

Excluding IP Prefixes on a Per-Interface Basis

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ip ospf prefix-suppression [disable]

5.    end

6.    show ip ospf interface

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Configures an interface type and enters interface configuration mode.

Step 4

ip ospf prefix-suppression [disable]

Example:

Device(config-if)# ip ospf prefix-suppression

Prevents OSPF from advertising IP prefixes that belong to a specific interface, except those that are associated with secondary IP addresses.

Note:
When you enter the ip ospf prefix suppressioncommand in interface configuration mode, it takes precedence over the prefix-suppression command that is entered in router configuration mode.

Step 5

end

Example:

Device(config-if)# end

Returns to privileged EXEC mode.

Step 6

show ip ospf interface

Example:

Device# show ip ospf interface

Displays OSPF-related interface information.

Note:
Use this command to verify that IP prefix suppression has been enabled for a specific interface.

Examples

In the following example, the output from the show ip ospf interface command verifies that prefix suppression has been enabled for Ethernet interface 0/0.

Device# show ip ospf interface

GigabitEthernet0/0 is up, line protocol is up
Internet Address 192.168.130.2/24, Area 2
Process ID 1, Router ID 10.0.0.6, Network Type BROADCAST, Cost: 10
Prefix-suppression is enabled
.
.
.

Troubleshooting IP Prefix Suppression

SUMMARY STEPS

1.    enable

2.    debug ip ospf lsa-generation

3.    debug condition interface interface-type interface-number [dlci dlci] [vc {vci | vpi | vci}]

4.    show debugging

5.    show logging [slot slot-number | summary]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

debug ip ospf lsa-generation

Example:

Device# debug ip ospf lsa-generation

Displays informations about each OSPF LSA generated.

Step 3

debug condition interface interface-type interface-number [dlci dlci] [vc {vci | vpi | vci}]

Example:

Device# debug interface serial 0/0

Limits output for some debug commands on the basis of the interface or virtual circuit.

Step 4

show debugging

Example:

Device# show debugging

Displays information about the types of debugging that are enabled for your router.

Step 5

show logging [slot slot-number | summary]

Example:

Device# show logging

Displays the state of syslog and the contents of the standard system logging buffer.

Examples

The following sample output from the debug ip ospf lsa-generation command verifies that for the Ethernet interface 0/0, IP prefixes from the connected network 192.168.131.0 are excluded.

Device# debug ip ospf lsa-generation

OSPF summary lsa generation debugging is on
Device# debug condition interface e0/0
Condition 1 set
Device# show debugging

IP routing:
OSPF summary lsa generation debugging is on
Condition 1: interface Et0/0 (1 flags triggered)
Flags: Et0/0
Device# show logging
*Jun  5 21:54:47.295: OSPF: Suppressing 192.168.131.0/24 on Ethernet1/0 from router LSA
*Jun  5 21:54:52.355: OSPF: Suppressing 192.168.131.0/24 on Ethernet1/0 from router LSA
.
.
.

Configuration Examples for Excluding Connected IP Prefixes from LSAs

- Excluding IP Prefixes from LSAs for an OSPF Process Example

- Excluding IP Prefixes from LSAs for a Specified Interface Example

Excluding IP Prefixes from LSAs for an OSPF Process Example

The following example configures IP prefix suppression for OSPF routing process 23.

router ospf 23
prefix-suppression
end

When the show ip ospf command is entered, the displayed output verifies that IP prefix suppression has been enabled for OSPF process 23.

Device# show ip ospf
outing Process "ospf 23" with ID 10.0.0.6
Start time: 00:00:04.912, Time elapsed: 00:02:35.184
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Link-local Signaling (LLS)
Supports area transit capability
It is an area border router
Router is not originating router-LSAs with maximum metric
Initial SPF schedule delay 5000 msecs
Minimum hold time between two consecutive SPFs 10000 msecs
Maximum wait time between two consecutive SPFs 10000 msecs
Incremental-SPF disabled
Minimum LSA interval 5 secs
Minimum LSA arrival 1000 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Number of external LSA 2. Checksum Sum 0x0132C8
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 3. 3 normal 0 stub 0 nssa
Number of areas transit capable is 1
External flood list length 0
IETF NSF helper support enabled
Cisco NSF helper support enabled
Prefix-suppression is enabled
.
.
.

Excluding IP Prefixes from LSAs for a Specified Interface Example

The following example configures the suppression of all IP prefixes that are associated with Ethernet interface 0/0:

interface Ethernet 0/0
ip ospf prefix-suppression
end

When the show ip ospf interface command is entered, the displayed output verifies that IP prefix suppression is enabled for Ethernet interface 0/0.

Device# show ip ospf interface

Ethernet0/0 is up, line protocol is up
Internet Address 192.168.130.2/24, Area 2
Process ID 1, Router ID 10.0.0.6, Network Type BROADCAST, Cost: 10
Prefix-suppression is enabled
.
.
.

Additional References

The following sections provide references related to the OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements feature.

Related Documents

Related Topic

Document Title

OSPF commands: complete command syntax, command mode, command history, command defaults, usage guidelines, and examples

Cisco IOS IP Routing: OSPF Command Reference

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

There are no new MIBs that are associated with this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

None

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements

Feature Name

Releases

Feature Information

OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements

The OSPF mechanism to exclude connected IP prefixes from LSA advertisements is deployed in large networks, limiting the number of IP prefixes that are carried in the OSPF LSAs can speed up OSPF convergence.

No new commands were introduced or modified.

Glossary

network LSA --The link-state advertisement created by the designated router (DR) or pseudonode that represents a group of routers on the same interface. The network LSA advertises summary information to represent the group of routers on the network.

router LSA --The link-state advertisement that is generated by a router. The router LSA advertises routing information (connected routes) for the router.

Chapter 38. OSPFv2 Local RIB

With the OSPFv2 Local RIB feature, each OSPF protocol instance has its own local Routing Information Base (RIB). The OSPF local RIB serves as the primary state for OSPF SPF route computation. The global RIB is not updated with intermediate results during the SPF. Instead, the global RIB is updated only when routes are added, deleted, or changed, thereby reducing global RIB computation. This reduced update activity may result in fewer dropped packets.

This feature is enabled by default and does not need to be configured. This document describes some optional configuration tasks to modify how the global and local RIBs function, although it is recommended to keep the default settings.

- Finding Feature Information

- Prerequisites for OSPFv2 Local RIB

- Restrictions for OSPFv2 Local RIB

- Information About OSPFv2 Local RIB

- How to Configure the OSPFv2 Local RIB Feature

- Configuration Examples for the OSPFv2 Local RIB Feature

- Additional References

- Feature Information for the OSPFv2 Local RIB Feature

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv2 Local RIB

Before this feature is configured, the OSPF routing protocol must be configured.

Restrictions for OSPFv2 Local RIB

This feature is available only for IP Version 4 networks.

Information About OSPFv2 Local RIB

- Function of the OSPF Local RIB

Function of the OSPF Local RIB

A device that is running OSPFv2 maintains a local RIB in which it stores all routes to destinations that it has learned from its neighbors. At the end of each SPF, OSPF attempts to install the best (that is, the least-cost) routes to a destination present in the local RIB into the global IPv4 routing table. The global RIB will be updated only when routes are added, deleted, or changed. Routes in the local RIB and Forwarding Information Base (FIB) will not compute when intermediate results are computed during SPF, resulting in fewer dropped packets in some circumstances.

By default, OSPF installs discard routes to null0 for any area range (internal) or summary-address (external) prefixes that it advertises to other devices. Installation of a discard route can prevent routing loops in cases where portions of a summary do not have a more specific route in the RIB. Normally, internal discard routes are installed with an administrative distance of 110, while external discard routes have an administrative distance of 254.

There may be rare circumstances, however, when some other values are needed. For example, if one OSPF process installs a route that exactly matches an area range configured on another OSPF process, the internal discard routes for the second OSPF process could be given a higher (less desirable) administrative distance.

By default, the contents of the global RIB are used to compute inter-area summaries, NSSA translation, and forwarding addresses for type-5 and type-7 LSAs. Each of these functions can be configured to use the contents of the OSPF local RIB instead of the global RIB for their computation. Using the local RIB for the computation may be slightly faster in some circumstances, but because the local RIB has information for only a particular instance of OSPF, using it for the computation may yield incorrect results. Potential problems that may occur include routing loops and black-hole routes.

How to Configure the OSPFv2 Local RIB Feature

Although it is recommended to keep the default settings for the commands described in the following sections, it is optional to change the defaults settings. This section describes the following optional tasks:

- Changing the Default Local RIB Criteria

- Changing the Administrative Distance for Discard Routes

Changing the Default Local RIB Criteria

Note

It is recommended that you not change the default values because they are conservative and preserve the current global RIB behavior.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id [vrf vpn-name]

4.    local-rib-criteria [forwarding-address] [inter-area-summary] [nssa-translation]

5.    end

6.    show ip ospf process-id rib [redistribution] [network-prefix] [network-mask] [detail]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id [vrf vpn-name]

Example:

Device(config)# router ospf 23

Configures an OSPFv2 routing process and enters router configuration mode.

Step 4

local-rib-criteria [forwarding-address] [inter-area-summary] [nssa-translation]

Example:

Device(config-router)# local-rib-criteria forwarding-address

Specifies that the OSPF local RIB will be used for route validation.

Step 5

end

Example:

Device(config-router)# end

Returns to privileged EXEC mode.

Step 6

show ip ospf process-id rib [redistribution] [network-prefix] [network-mask] [detail]

Example:

Device# show ip ospf 23 rib

Displays information for the OSPF local RIB or locally redistributed routes.

Changing the Administrative Distance for Discard Routes

Note

It is recommended to keep the default settings, but you can follow the steps in this section to change the administrative distance for discard routes.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospf process-id [vrf vpn-name]

4.    discard-route [external [distance]] [internal [distance]]

5.    end

6.    show ip route [ip-address [mask] [longer-prefixes] | protocol [process-id] | list [access-list-number | access-list-name] | static download]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospf process-id [vrf vpn-name]

Example:

Device(config)# router ospf 23

Configures an OSPFv2 routing process and enters router configuration mode.

Step 4

discard-route [external [distance]] [internal [distance]]

Example:

Device(config-router)# discard-route external 150

Reinstalls either an external or internal discard route that was previously removed.

Note:
You can now specify the administrative distance for internal and external discard routes.

Step 5

end

Example:

Device(config-router)# end

Returns to privileged EXEC mode.

Step 6

show ip route [ip-address [mask] [longer-prefixes] | protocol [process-id] | list [access-list-number | access-list-name] | static download]

Example:

Device# show ip route ospf 23

Displays the current state of the routing table.

Note:
Entering the show ip route command will verify the changed administrative distance values for external and internal discard routes.

Examples

The sample output displayed for the show ip route command confirms that the administrative distance for the IP route 192.168.0.0 255.255.255.0 is 110.

Device# show ip route 192.168.0.0 255.255.255.0

Routing entry for 192.168.0.0/24
Known via "ospf 1", distance 110, metric 0, type intra area
Routing Descriptor Blocks:
* directly connected, via Null0
Route metric is 0, traffic share count is 1

- Troubleshooting Tips

Troubleshooting Tips

You can research the output from the debug ip ospf rib command to learn about the function of the local RIB and the interaction between the route redistribution process and the global RIB. For example, you can learn why the routes that OSPF placed in the global RIB are not the same ones that you anticipated.

Configuration Examples for the OSPFv2 Local RIB Feature

- Example: Changing the Default Local RIB Criteria

- Example: Changing the Administrative Distance for Discard Routes

Example: Changing the Default Local RIB Criteria

In the following example, the local-rib-criteria command is entered without any keywords to specify that the local RIB will be used as criteria for all of the following options: forwarding address, inter-area summary, and NSSA translation.

router ospf 1
router-id 10.0.0.6
local-rib-criteria

Example: Changing the Administrative Distance for Discard Routes

In the following example, the administrative distance for external and internal discard routes is set to 25 and 30, respectively.

router ospf 1
router-id 10.0.0.6
log-adjacency-changes
discard-route external 25 internal 30
area 4 range 10.2.0.0 255.255.0.0
summary-address 192.168.130.2 255.255.255.0
redistribute static subnets
network 192.168.129.2 0.255.255.255 area 0
network 192.168.130.12 0.255.255.255 area 0

The output from the show ip route command verifies that the administrative distance for the internal route 10.2.0.0/16 is set to 30.

Device# show ip route 10.2.0.0 255.255.0.0
Routing entry for 10.2.0.0/16
Known via "ospf 1", distance 30, metric 1, type intra area
Routing Descriptor Blocks:
* directly connected, via Null0
Route metric is 1, traffic share count is 1

The output from the show ip route command verifies that the administrative distance for the external route 192.168.130.2/24 is set to 25.

Device# show ip route 192.168.130.2 255.255.255.0
Routing entry for 192.168.130.2/24
Known via "ospf 1", distance 25, metric 20, type intra area
Routing Descriptor Blocks:
* directly connected, via Null0
Route metric is 20, traffic share count is 1

Additional References

The following sections provide references related to the OSPFv2 Local RIB feature.

Related Documents

Related Topic

Document Title

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

OSPF configuration tasks

"Configuring OSPF"

Standards

Standard

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

--

MIBs

MIB

MIBs Link

No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

RFCs

RFC

Title

None

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for the OSPFv2 Local RIB Feature

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for the OSPFv2 Local RIB Feature

Feature Name

Releases

Feature Information

OSPFv2 Local RIB

12.4(15)T

With the OSPFv2 Local RIB feature, each OSPF protocol instance has its own local Routing Information Base (RIB). The OSPF local RIB serves as the primary state for OSPF SPF route computation. The global RIB is not updated with intermediate results during the SPF. Instead, the global RIB is updated only when routes are added, deleted, or changed, thereby reducing global RIB computation. This reduced update activity may result in fewer dropped packets.

This feature is enabled by default and does not need to be configured. This document describes some optional configuration tasks to modify how the global and local RIBs function, although it is recommended to keep the default settings.

The following commands were introduced or modified: debug ip ospf rib, discard-route, local-rib-criteria, show ip ospf rib.

Chapter 39. OSPFv3 MIB

The OSPFv3 MIB feature enables remote monitoring and troubleshooting of Open Shortest Path First version 3 (OSPFv3) processes using standard Simple Network Management Protocol (SNMP) management workstations. The protocol information collected by the OSPFv3 MIB objects and trap objects can be used to derive statistics that helps monitor and improve overall network performance.

- Finding Feature Information

- Prerequisites for OSPFv3 MIB

- Restrictions for OSPFv3 MIB Support

- Additional References for OSPFv3 MIB

- Feature Information for OSPFv3 MIB

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for OSPFv3 MIB

- Ensure that Open Shortest Path First version 3 (OSPFv3) is configured on the device.

- Ensure that Simple Network Management Protocol (SNMP) is enabled on the device before notifications (traps) can be configured or before SNMP GET operations can be performed.

Restrictions for OSPFv3 MIB Support

- To monitor multiple Open Shortest Path First version 3 (OSPFv3) processes, each process must be associated with a Simple Network Management Protocol (SNMP) context.

- To monitor multiple VRFs, each VRF must be associated with an SNMP context.

OSPFv3 MIB

Open Shortest Path First version 3 (OSPFv3) is the IPv6 implementation of OSPF. The OSPFv3 MIB is documented in RFC 5643 and defines a MIB for managing OSPFv3 processes through Simple Network Management Protocol (SNMP).

Users can constantly monitor the changing state of an OSPF network by using MIB objects. The MIB objects gather information relating to protocol parameters and trap notification objects that can signal the occurrence of significant network events such as transition state changes.

OSPFv3 TRAP MIB

The ospfv3Notifications MIB object contains the OSPFv3 trap MIB objects that enable and disable OSPF traps in the Cisco IOS CLI. These OSPFv3 trap MIB objects are provided by the RFC 5643 standard OSPFv3 MIB.

Enabling Specific OSPFv3 Traps

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    snmp-serverhost {hostname | ip-address} [vrf vrf-name] [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] community-string [udp-port port] [notification-type]

4.    snmp-server enable traps ospfv3 errors [bad-packet] [config-error] [virt-bad-packet] [virt-config-error]

5.    snmp-server enable traps ospfv3 rate-limit seconds trap-number

6.    snmp-server enable traps ospfv3 state-change [if-state-change] [neighbor-restart-helper-status-change] [neighbor-state-change] [nssa-translator-status-change] [restart-status-change] [virtif-state-change] [virtneighbor-restart-helper-status-change] [virtneighbor-state-change]

7.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

snmp-serverhost {hostname | ip-address} [vrf vrf-name] [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] community-string [udp-port port] [notification-type]

Example:

Device(config)# snmp-server host 172.20.2.162 version 2c public ospfv3

Specifies a recipient (target host) for Simple Network Management Protocol (SNMP) notification operations.

- If the notification-type is not specified, all enabled notifications (traps or informs) are sent to the specified host.

- If you want to send only the Open Shortest Path First version 3 (OSPFv3) notifications to the specified host, you can use the optional ospfv3 keyword as the notification-types . Entering the ospfv3 keyword enables the ospfv3Notifications MIB object.

Step 4

snmp-server enable traps ospfv3 errors [bad-packet] [config-error] [virt-bad-packet] [virt-config-error]

Example:

Device(config)# snmp-server enable traps ospfv3 errors

Enables SNMP notifications for OSPFv3 errors.

Step 5

snmp-server enable traps ospfv3 rate-limit seconds trap-number

Example:

Device(config)# snmp-server enable traps ospfv3 rate-limit 20 20

Sets the rate limit for the number of SNMP OSPFv3 notifications that are sent in each OSPFv3 SNMP notification rate-limit window.

Step 6

snmp-server enable traps ospfv3 state-change [if-state-change] [neighbor-restart-helper-status-change] [neighbor-state-change] [nssa-translator-status-change] [restart-status-change] [virtif-state-change] [virtneighbor-restart-helper-status-change] [virtneighbor-state-change]

Example:

Device(config)# snmp-server enable traps ospfv3 state-change

Enables SNMP OSPFv3 notifications for OSPFv3 transition state changes.

Step 7

end

Example:

Device(config)# end

Exits global configuration mode and enters privileged EXEC mode.

Verifying OSPFv3 MIB Traps on the Device

SUMMARY STEPS

1.    enable

2.    show running-config [options]

DETAILED STEPS

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

show running-config [options]

Example:

Device# show running-config | include traps

Displays the contents of the currently running configuration file and includes information about enabled traps.

- Verifies which traps are enabled.

Example: Enabling and Verifying OSPFv3 MIB Traps

The following example shows how to enable all OSPFv3 error traps:

Device> enable
Device# configure terminal
Device(config)# snmp-server enable traps ospfv3 errors
Device(config)# end

The following example shows how to verify that the traps are enabled:

Device> enable
Device# show running-config | include traps

snmp-server enable traps ospfv3 errors

Additional References for OSPFv3 MIB

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

OSPF configuration tasks

“Configuring OSPF” module in IP Routing: OSPF Configuration Guide

Standards and RFCs

Standard

Title

RFC 5643

Management Information Base for OSPFv3

MIBs

MIB

MIBs Link

OSPFv3-MIB

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 MIB

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 MIB

Feature Name

Releases

Feature Information

OSPFv3 MIB

15.2(4)M

The OSPFv3 MIB feature enables remote monitoring and troubleshooting of OSPFv3 processes using standard SNMP management workstations.

The following commands were introduced or modified: snmp-server host, snmp-server enable traps ospfv3 errors, snmp-server enable traps ospfv3 rate-limit, snmp-server enable traps ospfv3 state-change.

Chapter 40. TTL Security Support for OSPFv3 on IPv6

The Time To Live (TTL) Security Support for Open Shortest Path First version 3 (OSPFv3) on IPv6 feature increases protection against OSPFv3 denial of service attacks.

- Finding Feature Information

- Restrictions for TTL Security Support for OSPFv3 on IPv6

- Prerequisites for TTL Security Support for OSPFv3 on IPv6

- Information About TTL Security Support for OSPFv3 on IPv6

- How to Configure TTL Security Support for OSPFv3 on IPv6

- Configuration Examples for TTL Security Support for OSPFv3 on IPv6

- Additional References

- Feature Information for TTL Security Support for OSPFv3 on IPv6

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Restrictions for TTL Security Support for OSPFv3 on IPv6

- OSPFv3 TTL security can be configured for virtual and sham links only.

- OSPFv3 TTL security must be configured in IPv6 address family configuration mode (config-router-af). To enter IPv6 address family configuration mode you use the address-family ipv6 command.

- Sham links must not be configured on the default Virtual Routing and Forwarding (VRF).

Prerequisites for TTL Security Support for OSPFv3 on IPv6

The TTL Security Support for OSPFv3 on IPv6 feature is available only on platforms with OSPFv3 routing capabilities.

Information About TTL Security Support for OSPFv3 on IPv6

- OSPFv3 TTL Security Support for Virtual and Sham Links

OSPFv3 TTL Security Support for Virtual and Sham Links

In OSPFv3, all areas must be connected to a backbone area. If there is a break in backbone continuity, or the backbone is purposefully partitioned, you can establish a virtual link. The virtual link must be configured in the two devices you want to use to connect the partitioned backbone. The configuration information in each device consists of the other virtual endpoint (the other Area Border Router [ABR]) and the nonbackbone area that the two devices have in common (called the transit area.) Note that virtual links cannot be configured through stub areas. Sham links are similar to virtual links in many ways, but sham links are used in Layer 3 Multiprotocol Label Switching (MPLS) VPN networks to connect provider edge (PE) routers across the MPLS backbone.

Note

Multihop adjacencies such as virtual links and sham links use global IPv6 addresses that require you to configure TTL security to control the number of hops that a packet can travel.

If TTL security is enabled, OSPFv3 sends outgoing packets with an IP header TTL value of 255 and discards incoming packets that have TTL values less than the configurable threshold. Because each device that forwards an IP packet decreases the TTL value, packets received via a direct (one-hop) connection will have a value of 255. Packets that cross two hops will have a value of 254, and so on. The receive threshold is configured in terms of the maximum number of hops that a packet may have traveled. The value for this hop-count argument is a number from 1 to 254, with a default of 1.

To establish a virtual link or a sham link, use the area virtual-link or area sham-link cost commands respectively. To configure TTL security on a virtual link or a sham link, configure the ttl-security keyword and the hop-count argument in either command. Note that the hop-count argument value is mandatory in this case.

Note

OSPFv3 TTL Security can be configured for virtual and sham links only, and must be configured in address family configuration (config-router-af) mode for IPv6 address families.

How to Configure TTL Security Support for OSPFv3 on IPv6

- Configuring TTL Security Support on Virtual Links for OSPFv3 on IPv6

- Configuring TTL Security Support on Sham Links for OSPFv3 on IPv6

Configuring TTL Security Support on Virtual Links for OSPFv3 on IPv6

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    address-family ipv6 unicast vrf vrf-name

5.    area area-ID virtual-link router-id ttl-security hops hop-count

6.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables router configuration mode for the IPv4 or IPv6 address family.

Step 4

address-family ipv6 unicast vrf vrf-name

Example:

Device(config-router)# address-family ipv6 unicast vrf vrf1

Enters address family configuration mode for OSPFv3, specifies IPv6 unicast address prefixes, and specifies the name of the VRF instance to associate with subsequent address family configuration mode commands.

Step 5

area area-ID virtual-link router-id ttl-security hops hop-count

Example:

Device(config-router-af)# area 1 virtual-link 10.1.1.1 ttl-security hops 10

Defines an OSPFv3 virtual link and configures TTL security on the virtual link.

Step 6

end

Example:

Device(config-router-af)# end

(Optional) Returns to privileged EXEC mode.

Configuring TTL Security Support on Sham Links for OSPFv3 on IPv6

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    address-family ipv6 unicast vrf vrf-name

5.    area area-id sham-link source-address destination-address ttl-security hops hop-count

6.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

address-family ipv6 unicast vrf vrf-name

Example:

Device(config-router)# address-family ipv6 unicast vrf vrf1

Enters address family configuration mode for OSPFv3, specifies IPv6 unicast address prefixes, and specifies the name of the VRF instance to associate with subsequent address family configuration mode commands.

Step 5

area area-id sham-link source-address destination-address ttl-security hops hop-count

Example:

Device(config-router-af)# area 1 sham-link 2001:DB8:1::1 2001:DB8:0:A222::2 ttl-security hops 10

Defines an OSPFv3 sham link and configures TTL security on the sham link.

Step 6

end

Example:

Device(config-router-af)# end

(Optional) Returns to privileged EXEC mode.

Configuration Examples for TTL Security Support for OSPFv3 on IPv6

- Example: TTL Security Support on Virtual Links for OSPFv3 on IPv6

- Example: TTL Security Support on Sham Links for OSPFv3 on IPv6

Example: TTL Security Support on Virtual Links for OSPFv3 on IPv6

The following example shows how to configure TTL virtual link security:

Device> enable
Device# configure terminal
Device(config)# router ospfv3 1
Device(config-router)# address-family ipv6 unicast vrf vrf1
Device(config-router-af)# area 1 virtual-link 10.1.1.1 ttl-security hops 10
Device(config-router-af)# end
Device# show ospfv3 virtual-links
OSPFv3 1 address-family ipv6 (router-id 10.1.1.7)
Virtual Link OSPFv3_VL0 to router 10.1.1.2 is down
Interface ID 23, IPv6 address ::
Run as demand circuit
DoNotAge LSA allowed.
Transit area 1, Cost of using 65535
Transmit Delay is 1 sec, State DOWN,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Strict TTL checking enabled, up to 10 hops allowed

Example: TTL Security Support on Sham Links for OSPFv3 on IPv6

The following example shows how to configure TTL sham link security:

Device> enable
Device# configure terminal
Device(config)# router ospfv3 1
Device(config-router)# address-family ipv6 unicast vrf vrf1
Device(config-router-af)# area 1 sham-link 2001:DB8:1::1 2001:DB8:0:A222::2 ttl-security hops 10
Device(config-router-af)# end
Device#

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

IPv6 routing: OSPFv3

"IPv6 Routing: OSPFv3" module

MIBs

MIB

MIBs Link

No new or modified MIBs are supported, and support for existing MIBs has not been modified.

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

Click Here

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for TTL Security Support for OSPFv3 on IPv6

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

TTL Security Support for OSPFv3 on IPv6

Feature Name

Software Releases

Feature Information

TTL Security Support for OSPFv3 on IPv6

Cisco IOS Release 15.3(1)T

The TTL Security Support for OSPFv3 on IPv6 feature increases protection against OSPFv3 denial of service attacks.

The following commands were introduced or modified by this feature: area sham-link, area virtual-link.

Chapter 41. OSPFv3 VRF-Lite/PE-CE

The OSPFv3 VRF-Lite/PE-CE feature adds Open Shortest Path First version 3 (OSPFv3) support for nondefault VPN routing and forwarding (VRF) instances. OSPFv3 can be used as a provider-edge-customer-edge (PE-CE) routing protocol as specified in RFC 6565, OSPFv3 as a Provider Edge to Customer Edge (PE-CE) Routing Protocol. OSPFv3 in a nondefault VRF instance supports routing of IPv4 and IPv6 address families.

- Finding Feature Information

- Restrictions for OSPFv3 VRF-Lite/PE-CE

- Additional References for OSPFv3 VRF-Lite/PE-CE

- Feature Information for OSPFv3 VRF-Lite/PE-CE

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Restrictions for OSPFv3 VRF-Lite/PE-CE

In Cisco IOS Release 15.2(2)S and later releases, OSPFv3 interface commands in the ipv6 ospf format are no longer supported in VRF interface configuration mode. You must configure them in the new format, ospfv3.

The ospfv3 commands can have one of following formats:

- ospfv3 —Applies to all OSPFv3 processes and address families on a given interface.

- ospfv3 process-id —Applies to an OSPFv3 process with the configured process ID and to both IPv4 and IPv6 address families.

- ospfv3 process-id address-family-ID —Applies to an OSPFv3 process with the configured process ID and the configured address family.

More specific commands take precedence over less specific commands, as shown in the following descending order:

1. Commands that specify a process ID and an address family.

2. Commands that specify only a process ID.

3. Commands that specify neither a process ID nor an address family.

In Cisco IOS Release 15.2(2)S and later releases, you cannot use the ipv6 ospf router process-id command to configure OSPFv3 VRF instances. You must configure the router ospfv3 process-id command in global configuration mode and specify the address family for the configured VRF in router configuration mode.

Support for OSPFv3 VRF-Lite and PE-CE

Open Shortest Path First version 3 (OSPFv3) operates in nondefault VPN routing and forwarding (VRF) instances for both IPv6 and IPv4 address families and, transports the routes across a Border Gateway Protocol (BGP) or a Multiprotocol Label Switching (MPLS) backbone. On the provider edge (PE) device, customer routes are installed together by OSPFv3 and BGP in a common VRF or address family and each protocol is configured to redistribute the routes of the other. BGP combines the prefixes redistributed into it with a route-distinguisher value defined for the VRF and advertises them to other MPLS-BGP speakers in the same autonomous system using the VPNv4 or VPNv6 address family as appropriate.

The OSPFv3 route selection algorithm prefers intra-area routes across the back-door link over inter-area routes through the MPLS backbone. Sham-links are a type of virtual link across the MPLS backbone that connect OSPFv3 instances on different PEs. OSPFv3 instances tunnel protocol packets through the backbone and form adjacencies. Because OSPFv3 considers the sham-link as an intra-area connection, sham-link serves as a valid alternative to an intra-area back-door link.

Domain IDs are used to determine whether the routes are internal or external. They describe the administrative domain of the OSPFv3 instance from which the route originates. Every PE has a 48-bit primary domain ID (which may be NULL) and zero or more secondary domain IDs.

Configuring a VRF in an IPv6 Address Family for OSPFv3

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    vrf definition vrf-name

4.    rd route-distinguisher

5.    exit

6.    router ospfv3 [process-id]

7.    address-family ipv6 [unicast] [vrf vrf-name]

8.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

vrf definition vrf-name

Example:

Device(config)# vrf definition vrfsample

Configures a VRF routing table and enters VRF configuration mode.

Step 4

rd route-distinguisher

Example:

Device(config-vrf)# rd 10:1

Creates routing and forwarding tables for a VRF.

Step 5

exit

Example:

Device(config-vrf)# exit

Exists VRF configuration mode and returns to global configuration mode.

Step 6

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 2

Configures an OSPF routing process and enters router configuration mode.

Step 7

address-family ipv6 [unicast] [vrf vrf-name]

Example:

Device(config-router)# address-family ipv6 unicast vrf vrfsample

Configures an instance of the OSPFv3 process in the VRF routing table for the IPv6 address family and enters router address family configuration mode.

Step 8

end

Example:

Device(config-router-af)# end

Exists router address family configuration mode and returns to privileged EXEC mode.

Enabling an OSPFv3 IPv6 Address Family on a VRF Interface

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    vrf forwarding vrf-name [downstream vrf-name2]

5.    ipv6 enable

6.    ospfv3 process-id {ipv4 | ipv6} area area-id [instance instance-id]

7.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device# enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface Serial6/0

Specifies an interface type and number and enters interface configuration mode.

Step 4

vrf forwarding vrf-name [downstream vrf-name2]

Example:

Device(config-if)# vrf forwarding v1

Associates an interface with a VRF.

Step 5

ipv6 enable

Example:

Device(config-if)# ipv6 enable

Enables IPv6 processing on the interface that is associated with the VRF.

Step 6

ospfv3 process-id {ipv4 | ipv6} area area-id [instance instance-id]

Example:

Device(config-if)# ospfv3 1 ipv6 area 0

Enables the OSPFv3 IPv6 address family on the VRF interface.

Step 7

end

Example:

Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Configuring a Sham-Link for OSPFv3 PE-CE

Before You Begin

The OSPFv3 PE-CE feature supports direct forwarding on Border Gateway Protocol (BGP) routes.

Before you configure a sham-link, you must create a Multiprotocol Label Switching (MPLS) backbone, configure a device as an MPLS VPN PE device, and configure OSPFv3 as the provider-edge-customer-edge (PE-CE) protocol in a virtual routing and forwarding (VRF) instance.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface loopback interface-number

4.    description string

5.    vrf forwarding vrf-name

6.    ipv6 address ipv6-address/prefix-length

7.    ipv6 enable

8.    end

9.    router ospfv3 process-id

10.    address-family {ipv4 | ipv6} [unicast | multicast] [vrf vrf-name]

11.    redistribute process-id [options]

12.    area area-id sham-link source-address destination-address [cost number] [ttl-security hops hop-count]

13.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface loopback interface-number

Example:

Device(config)# interface loopback 0

Creates a loopback interface to be used as an endpoint of the sham-link on a provider edge device and enters interface configuration mode.

Step 4

description string

Example:

Device(config-if)# description Sham-link endpoint

Provides a description of the interface to help you track its status.

Step 5

vrf forwarding vrf-name

Example:

Device(config-if)# vrf forwarding vrf1

Associates the loopback interface with a VRF.

Step 6

ipv6 address ipv6-address/prefix-length

Example:

Device(config-if)# ipv6 address 2001:DB8:0:ABCD::1/48

Configures an IPv6 address of the loopback interface on a provider edge device.

Step 7

ipv6 enable

Example:

Device(config-if)# ipv6 enable

Enables IPv6 processing on the loopback interface.

Step 8

end

Example:

Device# end

Exits interface configuration mode and returns to global configuration mode.

Step 9

router ospfv3 process-id

Example:

Device(config)# router ospfv3 1

Enters router configuration mode.

Step 10

address-family {ipv4 | ipv6} [unicast | multicast] [vrf vrf-name]

Example:

Device(config-router)# address-family ipv6 unicast vrf vrf1

Enters IPv6 address family configuration mode for OSPFv3.

Step 11

redistribute process-id [options]

Example:

Device(config-router-af)# redistribute bgp 2

Redistributes IPv6 routes from the specified source BGP routing domain into the specified destination routing domain.
Note:
PE-CE redistribution is always from BGP.

Step 12

area area-id sham-link source-address destination-address [cost number] [ttl-security hops hop-count]

Example:

Device(config-router-af)# area 0 sham-link 2001:DB8:0:ABCD::1 2001:DB8:0:ABCD::2 cost 100

Enables the sham-link and specifies its source and destination addresses.

Step 13

end

Example:

Device(config-router-af)# end

Exits address family configuration mode and returns to privileged EXEC mode.

Configuring a Domain ID for an OSPFv3 PE-CE

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    vrf definition vrf-name

4.    rd route-distinguisher

5.    exit

6.    router ospfv3 [process-id]

7.    address-family ipv6 [unicast] [vrf vrf-name]

8.    domain-id type type value hex-value

9.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

vrf definition vrf-name

Example:

Device(config)# vrf definition vrfsample

Configures a VRF routing table and enters VRF configuration mode.

Step 4

rd route-distinguisher

Example:

Device(config-vrf)# rd 10:1

Creates routing and forwarding tables for a VRF.

Step 5

exit

Example:

Device(config-vrf)# exit

Exists VRF configuration mode and returns to global configuration mode.

Step 6

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 2

Enters router configuration mode.

Step 7

address-family ipv6 [unicast] [vrf vrf-name]

Example:

Device(config-router)# address-family ipv6 unicast vrf vrfsample

Configures an instance of the OSPFv3 process in the VRF routing table for the IPv6 address family and enters address family configuration mode..

Step 8

domain-id type type value hex-value

Example:

Device(config-router-af)# domain-id type 0205 value 800EFFFF12AB

Configures the BGP domain ID.

- The value for type can be 0005, 0105, 0205, or 8005.

- The value for value is an arbitrary 48-bit number encoded as 12 hexadecimal digits.

Step 9

end

Example:

Device(config-router-af)# end

Exists router address family mode and returns to privileged EXEC mode.

Configuring VRF-Lite Capability for OSPFv3

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    vrf definition vrf-name

4.    rd route-distinguisher

5.    exit

6.    router ospfv3 [process-id]

7.    address-family ipv6 [unicast] [vrf vrf-name]

8.    capability vrf-lite

9.    end

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

vrf definition vrf-name

Example:

Device(config)# vrf definition vrfsample

Configures a VRF routing table and enters VRF configuration mode.

Step 4

rd route-distinguisher

Example:

Device(config-vrf)# rd 10:1

Creates routing and forwarding tables for a VRF.

Step 5

exit

Example:

Device(config-vrf)# exit

Exists VRF configuration mode and returns to global configuration mode.

Step 6

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 2

Enables router configuration mode for the IPv4 or IPv6 address family.

Step 7

address-family ipv6 [unicast] [vrf vrf-name]

Example:

Device(config-router)# address-family ipv6 unicast vrf vrfsample

Configures an instance of the OSPFv3 process in the VRF routing table for the IPv6 address family and enters address family configuration mode.

Step 8

capability vrf-lite

Example:

Device(config-router-af)# capability vrf-lite

Applies the multi-VRF capability to the OSPF process.

Step 9

end

Example:

Device(config-router-af)# end

Exists router address family mode and returns to privileged EXEC mode.

Example: Configuring a Provider Edge Device to Provide IPv6 and IPv4 Routing

The following example shows how to configure a provider edge (PE) device to provide IPv6 and IPv4 routing for a user on VRF “v1” and IPv6 routing for a user on VRF “v2”:

vrf definition v1
rd 1:1
route-target export 100:1
route-target import 100:1
!
address-family ipv4
exit-address-family
!
address-family ipv6
exit-address-family
!
vrf definition v2
rd 2:2
route-target export 200:2
route-target import 200:2
!
address-family ipv6
exit-address-family
!
interface Loopback1
vrf forwarding v1
ipv6 address 2001:DB8:0:ABCD::1/48
!
interface Serial5/0
vrf forwarding v2
no ip address
ipv6 address 2001:DB8:0:ABCD::3/48
ospfv3 1 ipv6 area 1
!
interface Serial6/0
vrf forwarding v1
ip address 10.0.0.1 255.255.255.0
ipv6 enable
ospfv3 1 ipv6 area 0
ospfv3 1 ipv4 area 10.1.1.1
!
router ospfv3
!
log-adjacency-changes detail
!
address-family ipv4 unicast vrf v1
router-id 10.2.2.2
redistribute bgp 1
exit-address-family
!
address-family ipv6 unicast vrf v1
router-id 2001:DB8:1::1
domain-id type 0205 value 111111222222
area 0 sham-link 2001:DB8:0:ABCD::5 2001:DB8:0:ABCD::7
redistribute bgp 1
exit-address-family
address-family ipv6 unicast vrf v2
router-id 2001:DB8:1::3
redistribute bgp 1
exit
!
router bgp 1
bgp router-id 10.3.3.3
no bgp default ipv4-unicast
neighbor 10.0.0.4 remote-as 1
neighbor 10.0.0.4 update-source-Loopback0
!
address-family ipv4
exit-address-family
!
address-family vpnv4
neighbor 10.0.0.4
neighbor 10.0.0.4 send-community extended
exit-address-family
!
address-family vpnv6
neighbor 10.0.0.4 activate
neighbor 10.0.0.4 send-community extended
exit-address-family
!
address-family ipv4 vrf v1
redistribute ospfv3 1
exit-address-family
!
address-family ipv6 vrf v1
redistribute ospf 1
exit-address-family
!
address-family ipv6 vrf v2
redistribute ospf 1
exit-address-family
!

Example: Configuring a Provider Edge Device for VRF-Lite

vrf definition v1
rd 1:1
!
address-family ipv4
exit-address-family
!
address-family ipv6
exit-address-family
!
vrf definition v2
rd 2:2
!
address-family ipv6
exit-address-family
!
interface FastEthernet0/0
no ip address
!
interface FastEthernet0/0.100
encapsulation dot1Q 100
vrf forwarding v1
ip address 192.168.1.1 255.255.255.0
ipv6 enable
ospfv3 1 ipv6 area 0
ospfv3 1 ipv4 area 0
!
interface FastEthernet0/0.200
encapsulation dot1Q 200
vrf forwarding v2
ipv6 enable
ospfv3 1 ipv6 area 0
!
interface FastEthernet0/1
rf forwarding v1
ip address 10.1.1.1 255.255.255.0
ipv6 enable
ospfv3 1 ipv6 area 1
ospfv3 1 ipv4 area 0
no keepalive
!
interface FastEthernet0/2
vrf forwarding v2
no ip address
ipv6 address 2001:DB8:1::1
ipv6 enable
ospfv3 1 ipv6 area 1
!
router ospfv3 1
!
address-family ipv6 unicast vrf v2
router-id 192.168.2.1
capability vrf-lite
exit-address-family
!
address-family ipv4 unicast vrf v1
router-id 192.168.1.4
capability vrf-lite
exit-address-family
!
address-family ipv6 unicast vrf v1
router-id 192.168.1.1
capability vrf-lite
exit-address-family
!

Additional References for OSPFv3 VRF-Lite/PE-CE

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

RFCs

RFC

Title

RFC 5838

Support of Address Families in OSPFv3

RFC 6565

OSPFv3 as a Provider Edge to Customer Edge (PE-CE) Routing Protocol

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 VRF-Lite/PE-CE

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 VRF-Lite/PE-CE

Feature Name

Releases

Feature Information

OSPFv3 VRF-Lite/PE-CE

The OSPFv3 VRF-Lite/PE-CE feature adds OSPFv3 support for nondefault VRF instances.

The following commands were introduced or modified: area sham-link (OSPFv3), capability vrf-lite (OSPFv3).

Chapter 42. Graceful Shutdown Support for OSPFv3

This feature provides the ability to temporarily shut down an Open Shortest Path First version 3 (OSPFv3) process or interface in the least disruptive manner, and to notify its neighbors that it is going away. A graceful shutdown of a protocol can be initiated on all OSPFv3 interfaces or on a specific interface.

- Finding Feature Information

- Additional References for Graceful Shutdown Support for OSPFv3

- Feature Information for Graceful Shutdown Support for OSPFv3

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

OSPFv3 Graceful Shutdown

The Graceful Shutdown for OSPFv3 feature provides the ability to temporarily shut down the OSPFv3 protocol in the least disruptive manner and to notify its neighbors that it is going away. All traffic that has another path through the network will be directed to that alternate path. A graceful shutdown of the OSPFv3 protocol can be initiated using the shutdown command in router configuration mode or in address family configuration mode.

This feature also provides the ability to shut down OSPFv3 on a specific interface. In this case, OSPFv3 will not advertise the interface or form adjacencies over it; however, all of the OSPFv3 interface configuration will be retained. To initiate a graceful shutdown of an interface, use the ipv6 ospf shutdown or the ospfv3 shutdown command in interface configuration mode.

Configuring Graceful Shutdown of the OSPFv3 Process

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    Do one of the following:

- ipv6 router ospf process-id

- router ospfv3 process-id

4.    shutdown

5.    end

6.    Do one of the following:

- show ipv6 ospf [process-id]

- show ospfv3 [process-id]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

Do one of the following:

- ipv6 router ospf process-id

- router ospfv3 process-id

Example:

Device(config)# ipv6 router ospf 1

Example:

Device(config)# router ospfv3 101

Enables OSPFv3 routing and enters router configuration mode.

Step 4

shutdown

Example:

Device(config-router)# shutdown

Shuts down the selected interface.

Step 5

end

Example:

Device(config-router)# end

Returns to privileged EXEC mode.

Step 6

Do one of the following:

- show ipv6 ospf [process-id]

- show ospfv3 [process-id]

Example:

Device# show ipv6 ospf

Example:

Device# show ospfv3

(Optional) Displays general information about OSPFv3 routing processes.

Configuring Graceful Shutdown of the OSPFv3 Process in Address-Family Configuration Mode

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 [process-id]

4.    address-family ipv6 unicast [vrf vrf-name]

5.    shutdown

6.    end

7.    show ospfv3 [process-id]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id]

Example:

Device(config)# router ospfv3 1

Enables router configuration mode for the IPv6 address family.

Step 4

address-family ipv6 unicast [vrf vrf-name]

Example:

Device(config-router)#address-family ipv6

Enters IPv6 address family configuration mode for OSPFv3.

Step 5

shutdown

Example:

Device(config-router-af)# shutdown

Shuts down the selected interface.

Step 6

end

Example:

Device(config-router-af)# end

Returns to privileged EXEC mode.

Step 7

show ospfv3 [process-id]

Example:

Device# show ospfv3

(Optional) Displays general information about OSPFv3 routing processes.

Configuring OSPFv3 Graceful Shutdown of the OSPFv3 Interface

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    Do one of the following:

- ipv6 ospf shutdown

- ospfv3 shutdown

5.    end

6.    show ospfv3 process-id area-id address-family [ vrf {vrf-name | * }] interface [type number] [brief]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface GigabitEthernet

Configures an interface type and number and enters interface configuration mode.

Step 4

Do one of the following:

- ipv6 ospf shutdown

- ospfv3 shutdown

Example:

Device(config-if)# ipv6 ospf shutdown

Example:

Device(config-if)# ospfv3 process-id ipv6 shutdown

Initiates an OSPFv3 protocol graceful shutdown at the interface level.

- When the ipv6 ospf shutdown interface command is entered, the interface on which it is configured sends a link-state update advising its neighbors that is going down, which allows those neighbors to begin routing OSPFv3 traffic around this device.

Step 5

end

Example:

Device(config-if)# end

Returns to privileged EXEC mode.

Step 6

show ospfv3 process-id area-id address-family [ vrf {vrf-name | * }] interface [type number] [brief]

Example:

Device# show ospfv3 1 interface

(Optional) Displays OSPFv3-related interface information.

Example: Configuring Graceful Shutdown of the OSPFv3 Process

The following example shows how to configure graceful shutdown of the OSPFv3 process in IPv6 router OSPF configuration mode configuration mode:

ipv6 router ospf 6
router-id 10.10.10.10
shutdown

The following example shows how to configure graceful shutdown of the OSPFv3 process in router OSPFv3 configuration mode:

!
router ospfv3 1
shutdown
!
address-family ipv6 unicast
exit-address-family

The following example shows how to configure graceful shutdown of the OSPFv3 process in address-family configuration mode:

!
router ospfv3 1
!
address-family ipv6 unicast
shutdown
exit-address-family

Example: Configuring Graceful Shutdown of the OSPFv3 Interface

The following example shows how to configure graceful shutdown of the OSPFv3 interface using the ipv6 ospf shutdown command:

!
interface Serial2/1
no ip address
ipv6 enable
ipv6 ospf 6 area 0
ipv6 ospf shutdown
serial restart-delay 0
end

The following example shows how to configure graceful shutdown of the OSPFv3 interface using the ospfv3 shutdown command:

!
interface Serial2/0
ip address 10.10.10.10 255.255.255.0
ip ospf 1 area 0
ipv6 enable
ospfv3 shutdown
ospfv3 1 ipv6 area 0
serial restart-delay 0
end

Additional References for Graceful Shutdown Support for OSPFv3

Related Documents

Related Topic

Document Title

Configuring OSPF

“Configuring OSPF”

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for Graceful Shutdown Support for OSPFv3

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for Graceful Shutdown Support for OSPFv3

Feature Name

Releases

Feature Information

Graceful Shutdown Support for OSPFv3

15.3(2)T

This feature provides the ability to temporarily shut down an Open Shortest Path First version 3 (OSPFv3) process or interface in the least disruptive manner, and to notify its neighbors that it is going away.

A graceful shutdown of a protocol can be initiated on all OSPFv3 interfaces or on a specific interface.

The following commands were introduced:

- ipv6 ospf shutdown

- ospfv3 shutdown

- shutdown (router ospfv3)

Chapter 43. Prefix Suppression Support for OSPFv3

This feature enables Open Shortest Path First version 3 (OSPFv3) to hide the IPv4 and IPv6 prefixes of connected networks from link-state advertisements (LSAs). When OSPFv3 is deployed in large networks, limiting the number of IPv4 and IPv6 prefixes that are carried in the OSPFv3 LSAs can speed up OSPFv3 convergence.

This feature can also be utilized to enhance the security of an OSPFv3 network by allowing the network administrator to prevent IP routing toward internal nodes.

- Finding Feature Information

- Prerequisites for Prefix Suppression Support for OSPFv3

- Additional References for Prefix Suppression Support for OSPFv3

- Feature Information for Prefix Suppression Support for OSPFv3

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

Prerequisites for Prefix Suppression Support for OSPFv3

Before you can use the mechanism to exclude IPv4 and IPv6 prefixes from LSAs, the OSPFv3 routing protocol must be configured.

OSPFv3 Prefix Suppression Support

The OSPFv3 Prefix Suppression Support feature allows you to hide IPv4 and IPv6 prefixes that are configured on interfaces running OSPFv3.

In OSPFv3, addressing semantics have been removed from the OSPF protocol packets and the main LSA types, leaving a network-protocol-independent core. This means that Router-LSAs and network-LSAs no longer contain network addresses, but simply express topology information. The process of hiding prefixes is simpler in OSPFv3 and suppressed prefixes are simply removed from the intra-area-prefix-LSA. Prefixes are also propagated in OSPFv3 via link LSAs

The OSPFv3 Prefix Suppression feature provides a number of benefits.The exclusion of certain prefixes from adverstisements means that there is more memory available for LSA storage, bandwidth and buffers for LSA flooding, and CPU cycles for origination and flooding of LSAs and for SPF computation. Prefixes are also filtered from link LSAs. A device only filters locally configured prefixes, not prefixes learnt via link LSAs. In addition, security has been improved by reducing the possiblity of remote attack with the hiding of transit-only networks.

Globally Suppress IPv4 and IPv6 Prefix Advertisements by Configuring the OSPFv3 Process

You can reduce OSPFv3 convergence time by configuring the OSPFv3 process on a device to prevent the advertisement of all IPv4 and IPv6 prefixes by using the prefix-suppression command in router configuration mode or address-family configuration mode.

Note

Prefixes that are associated with loopbacks, secondary IP addresses, and passive interfaces are not suppressed by the router mode or the address-family configuration commands because typical network designs require prefixes to remain reachable.

Suppress IPv4 and IPv6 Prefix Advertisements on a Per-Interface Basis

You can explicitly configure an OSPFv3 interface not to advertise its IP network to its neighbors by using the ipv6 ospf prefix-suppression command or the ospfv3 prefix-suppression command in interface configuration mode.

Note

If you have globally suppressed IPv4 and IPv6 prefixes from connected IP networks by configuring the prefix-suppression router configuration command, the interface configuration command takes precedence over the router configuration command.

Configuring Prefix Suppression Support of the OSPFv3 Process

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 process-id [vrf vpn-name]

4.    prefix-suppression

5.    end

6.    show ospfv3

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 process-id [vrf vpn-name]

Example:

Device(config)# router ospfv3 23

Configures an OSPFv3 routing process and enters router configuration mode.

Step 4

prefix-suppression

Example:

Device(config-router)# prefix-suppression

Prevents OSPFv3 from advertising all IPv4 and IPv6 prefixes, except prefixes that are associated with loopbacks, secondary IP addresses, and passive interfaces.

Step 5

end

Example:

Device(config-router)# end

Returns to privileged EXEC mode.

Step 6

show ospfv3

Example:

Device# show ospfv3

Displays general information about OSPFv3 routing processes.

Note:
Use this command to verify that IPv4 and IPv6 prefix suppression has been enabled.

Configuring Prefix Suppression Support of the OSPFv3 Process in Address-Family Configuration Mode

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 process-id [vrf vpn-name]

4.    address-family ipv6 unicast

5.    prefix-suppression

6.    end

7.    show ospfv3

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 process-id [vrf vpn-name]

Example:

Device(config)# router ospfv3 23

Configures an OSPFv3 routing process and enters router configuration mode.

Step 4

address-family ipv6 unicast

Example:

Device(config-router)# address-family ipv6 unicast

Enters IPv6 address family configuration mode for OSPFv3.

Step 5

prefix-suppression

Example:

Device(config-router-af)# prefix-suppression

Prevents OSPFv3 from advertising all IPv4 and IPv6 prefixes, except prefixes that are associated with loopbacks, secondary IP addresses, and passive interfaces.

Step 6

end

Example:

Device(config-router-af)# end

Returns to privileged EXEC mode.

Step 7

show ospfv3

Example:

Device# show ospfv3

Displays general information about OSPFv3 routing processes.

Note:
Use this command to verify that IPv4 and IPv6 prefix suppression has been enabled.

Configuring Prefix Suppression Support on a Per-Interface Basis

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    Do one of the following:

- ipv6 ospf prefix-suppression [disable]

- ospfv3 prefix-suppression disable

5.    end

6.    show ospfv3 interface

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:

Device(config)# interface serial 0/0

Configures an interface type and enters interface configuration mode.

Step 4

Do one of the following:

- ipv6 ospf prefix-suppression [disable]

- ospfv3 prefix-suppression disable

Example:

Device(config-if)# ipv6 ospf prefix-suppression

Example:

Device(config-if)# ospfv3 1 prefix-suppression disable

Prevents OSPFv3 from advertising IPv4 and IPv6 prefixes that belong to a specific interface, except those that are associated with secondary IP addresses.

- When you enter the ipv6 ospf prefix-suppression command or the ospfv3 prefix-suppression command in interface configuration mode, it takes precedence over the prefix-suppression command that is entered in router configuration mode.

Step 5

end

Example:

Device(config-if)# end

Returns to privileged EXEC mode.

Step 6

show ospfv3 interface

Example:

Device# show ospfv3 interface

Displays OSPFv3-related interface information.

Note:
Use this command to verify that IPv4 and IPv6 prefix suppression has been enabled for a specific interface.

Troubleshooting IPv4 and IPv6 Prefix Suppression

SUMMARY STEPS

1.    enable

2.    debug ospfv3 lsa-generation

3.    debug condition interface interface-type interface-number [dlci dlci] [vc {vci | vpi | vci}]

4.    show debugging

5.    show logging [slot slot-number | summary]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

debug ospfv3 lsa-generation

Example:

Device# debug ospfv3 lsa-generation

Displays informations about each OSPFv3 LSA that is generated.

Step 3

debug condition interface interface-type interface-number [dlci dlci] [vc {vci | vpi | vci}]

Example:

Device# debug condition interface serial 0/0

Limits output for some debug commands on the basis of the interface or virtual circuit.

Step 4

show debugging

Example:

Device# show debugging

Displays information about the types of debugging that are enabled for your device.

Step 5

show logging [slot slot-number | summary]

Example:

Device# show logging

Displays the state of syslog and the contents of the standard system logging buffer.

Example: Configuring Prefix Suppression Support for OSPFv3

The following example shows how to configure prefix suppression support for OSPFv3 in router configuration mode:

router ospfv3 1
prefix-suppression
!
address-family ipv6 unicast
router-id 0.0.0.6
exit-address-family

The following example shows how to configure prefix suppression support for OSPFv3 in address-family configuration mode:

router ospfv3 1
!
address-family ipv6 unicast
router-id 10.0.0.6
prefix-suppression
exit-address-family

The following example shows how to configure prefix suppression support for OSPFv3 in interface configuration mode:

interface Ethernet0/0
ip address 10.0.0.1 255.255.255.0
ipv6 address 2001:201::201/64
ipv6 enable
ospfv3 prefix-suppression
ospfv3 1 ipv4 area 0
ospfv3 1 ipv6 area 0
end

Additional References for Prefix Suppression Support for OSPFv3

Related Documents

Related Topic

Document Title

Configuring OSPF

“Configuring OSPF”

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for Prefix Suppression Support for OSPFv3

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for Prefix Suppression Support for OSPFv3

Feature Name

Releases

Feature Information

Prefix Suppression Support for OSPFv3

This feature enables Open Shortest Path First version 3 (OSPFv3) to hide the IPv4 and IPv6 prefixes of connected networks from link-state advertisements (LSAs).

This feature can also be used to enhance the security of an OSPFv3 network by allowing the network administrator to prevent IP routing toward internal nodes.

The following commands were introduced or modified:

- ipv6 ospf prefix-suppression

- ospfv3 prefix-suppression

- prefix-suppression (OSPFv3)

Chapter 44. OSPFv3 ABR Type 3 LSA Filtering

This feature extends the ability of an Area Border Router (ABR) that is running the Open Shortest Path First version 3 (OSPFv3) protocol to filter type 3 link-state advertisements (LSAs) that are sent between different OSPFv3 areas. This feature allows only packets with specified prefixes to be sent from one area to another area and restricts all packets with other prefixes. This type of area filtering can be applied out of a specific OSPFv3 area, into a specific OSPFv3 area, or into and out of the same OSPFv3 areas at the same time.

- Finding Feature Information

- OSPFv3 ABR Type 3 LSA Filtering

- Additional References for OSPFv3 ABR Type 3 LSA Filtering

- Feature Information for OSPFv3 ABR Type 3 LSA Filtering

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to Click Here . An account on Cisco.com is not required.

OSPFv3 ABR Type 3 LSA Filtering

Only type 3 LSAs that originate from an ABR are filtered.

Area Filter Support

OSPFv3 area filters allow the filtering of inter-area prefix LSAs on the ABRs. The filter, based on IPv6 prefix lists, can be applied in both directions. In the “in” direction, it filters out the LSAs coming from all other areas when sending the inter-area prefix LSAs into the specified area. In the “out” direction, it filters out the inter-area prefix LSAs generated for the specified area.

The Area Filter Support feature gives the administrator improved control of route distribution between OSPFv3 areas.

Configuring Area Filter Support for OSPFv3

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router ospfv3 process-id

4.    area area-id filter-list prefix prefix-list-name {in | out}

5.    end

6.    ipv6 prefix-list list-name [seq seq-number] {deny ipv6-prefix/prefix-length | permit ipv6-prefix/prefix-length | description text} [ge ge-value] [le le-value]

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

- Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 process-id

Example:

Device(config)# router ospfv3 1

Configures the router to run an OSPFv3 process.

Step 4

area area-id filter-list prefix prefix-list-name {in | out}

Example:

Device(config-router)# area 1 filter-list prefix test_ipv6 out

Configures the router to filter interarea routes out of the specified area.

Step 5

end

Example:

Device(config-router)# end

Returns to global configuration mode.

Step 6

ipv6 prefix-list list-name [seq seq-number] {deny ipv6-prefix/prefix-length | permit ipv6-prefix/prefix-length | description text} [ge ge-value] [le le-value]

Example:

Device(config)# ipv6 prefix-list test_ipv6 seq 5 permit 2011::1/128

Creates a prefix list with the name specified for the list-name argument.

Example: Area Filter Support for OSPFv3

The following example shows how to configure Area Filter Support for OSPFv3:

router ospfv3 1
!
address-family ipv4 unicast
area 2 filter-list prefix test_ipv4 in
exit-address-family
!
address-family ipv6 unicast
area 2 filter-list prefix test_ipv6 in
exit-address-family
!
ip prefix-list test_ipv4 seq 5 permit 2.2.2.2/32
!
!
ipv6 prefix-list test_ipv6 seq 5 deny 2011::1/128

Additional References for OSPFv3 ABR Type 3 LSA Filtering

Related Documents

Related Topic

Document Title

Configuring OSPF

“Configuring OSPF”

OSPF commands

Cisco IOS IP Routing: OSPF Command Reference

Cisco IOS master command list, all releases

Cisco IOS Master Command List, All Releases

Standards

Standard

Title

No new or modified standards are supported and support for existing standards has not been modified.

—

RFCs

RFC

Title

No new or modified RFCs are supported and support for existing RFCs has not been modified.

—

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

Click Here

Feature Information for OSPFv3 ABR Type 3 LSA Filtering

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.

Feature Information for OSPFv3 ABR Type 3 LSA Filtering

Feature Name

Releases

Feature Information

OSPFv3 ABR Type 3 LSA Filtering

15.3(1)S

15.2(1)E

The OSPFv3 ABR Type 3 LSA Filtering feature extends the ability of an ABR that is running the OSPFv3 protocol to filter type 3 LSAs that are sent between different OSPFv3 areas. This feature allows only packets with specified prefixes to be sent from one area to another area and restricts all packets with other prefixes. This type of area filtering can be applied out of a specific OSPFv3 area, into a specific OSPFv3 area, or into and out of the same OSPFv3 areas at the same time.