Table Of Contents
BGP Dynamic Update Peer-Groups
Information About BGP Dynamic Update Peer-Groups
BGP Update Generation and Dynamic Update Peer-Groups
BGP Dynamic Update Peer-Groups and BGP Configuration Using Peer Templates
BGP Dynamic Update Peer-Group Configuration
How to Monitor and Maintain BGP Dynamic Update Peer-Groups
Clearing BGP Update-Group Member Sessions
Troubleshooting and Processing BGP Update-Groups
Displaying BGP Update-Group Statistics
Displaying Information About the Processing of BGP Update-Groups
Configuration Examples for BGP Dynamic Update Peer-Groups
Clearing BGP Update-Group Member Sessions: Example
Troubleshooting the Processing of BGP Update-Groups: Example
Displaying BGP Update-Group Statistics: Example
Displaying Information About the Processing of BGP Update Groups: Example
BGP Dynamic Update Peer-Groups
The BGP Dynamic Update Peer-Groups feature introduces a new algorithm that dynamically calculates and optimizes update-groups of neighbors that share the same outbound policies and can share the same update messages. In previous versions of Cisco IOS software, Border Gateway Protocol (BGP) update messages were grouped together based on peer-group configurations. This method of grouping updates limited outbound policies and specific-session configurations. The BGP Dynamic Update Peer-Group feature separates update-group replication from peer-group configuration, which improves convergence time and flexibility of neighbor configuration.
Feature History for the BGP Dynamic Update Peer-Groups Feature
Finding Support Information for Platforms and Cisco IOS Software Images
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Contents
•Information About BGP Dynamic Update Peer-Groups
•How to Monitor and Maintain BGP Dynamic Update Peer-Groups
•Configuration Examples for BGP Dynamic Update Peer-Groups
Information About BGP Dynamic Update Peer-Groups
To support this feature, you must understand the following concepts:
•BGP Update Generation and Dynamic Update Peer-Groups
•BGP Dynamic Update Peer-Groups and BGP Configuration Using Peer Templates
•BGP Dynamic Update Peer-Group Configuration
BGP Update Generation and Dynamic Update Peer-Groups
In previous versions of Cisco IOS software, BGP update messages were grouped based on peer-group configurations. This method of grouping neighbors for BGP update message generation reduced the amount of system processing resources needed to process the routing table. This method, however, had the following limitations:
•All neighbors that shared the same peer-group configuration also had to share the same outbound routing policies.
•All neighbors had to belong to the same peer-group and address-family. Neighbors configured in different peer-groups cannot belong to different address-families.
These limitations existed to balance optimal update generation and replication against peer-group configuration. These limitations also caused the network operator to configure smaller peer-groups, which reduced the efficiency of update message generation.
The introduction of the BGP Dynamic Update Peer-Groups feature separates BGP update generation from peer-group configuration. The BGP Dynamic Update Peer-Groups feature introduces an algorithm that dynamically calculates BGP update-group membership based on outbound routing policies. This feature does not require any configuration by the network operator. Optimal BGP update message generation occurs automatically and independently. BGP neighbor configuration is no longer restricted by outbound routing policies, and update-groups can belong to different address families.
BGP Dynamic Update Peer-Groups and BGP Configuration Using Peer Templates
The BGP Dynamic Update Peer-Groups feature was introduced with the BGP Configuration Using Peer Templates feature. The BGP Dynamic Peer-Groups feature improves the performance of BGP update message generation. The BGP Configuration Using Peer Templates feature improves the flexibility of BGP neighbor configuration through the introduction of peer-policy and peer-session configuration templates. Peer-policy configuration templates are used to configure policy-related commands. Peer-session configuration templates are used for the configuration of general session commands. Peer configuration templates support inheritance and more robust and flexible configurations.
With the configuration of the BGP Configuration Using Templates feature and the support of the BGP Dynamic Update Peer-Groups features, the network operator no longer needs to configure peer-groups in BGP and can benefit from improved configuration flexibility and system performance. For more information about the BGP Configuration Using Templates feature, refer to the BGP Configuration Using Peer Templates document.
BGP Dynamic Update Peer-Group Configuration
The BGP Dynamic Update Peer-Group feature requires no configuration and occurs automatically. When a change to outbound policy occurs, the router automatically recalculates update-group memberships and applies the changes by triggering an outbound soft reset after a 1 minute timer expires. This behavior is designed to provide the network operator with time to change the configuration if a mistake is made. You can manually enable an outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command.
Note In Cisco IOS Release 12.0(25)S, 12.3(2)T, and prior releases the update group recalculation delay timer is set to 3 minutes.
For the best optimization of BGP update-group generation, we recommend that the network operator keeps outbound routing policy the same for neighbors that have similar outbound policies. This feature introduces new commands for monitoring and maintaining BGP update-groups. For more information about the new commands, see the section "How to Monitor and Maintain BGP Dynamic Update Peer-Groups."
How to Monitor and Maintain BGP Dynamic Update Peer-Groups
This section contains the following procedures:
•Clearing BGP Update-Group Member Sessions (optional)
•Troubleshooting the Processing of BGP Update-Groups: Example (optional)
•Displaying BGP Update-Group Statistics: Example (optional)
•Displaying BGP Update-Group Statistics: Example(optional)
Clearing BGP Update-Group Member Sessions
Perform this task to clear BGP update-group member sessions:
SUMMARY STEPS
1. enable
2. clear ip bgp update-group [index-group | ip-address]
DETAILED STEPS
Troubleshooting and Processing BGP Update-Groups
Perform this task to troubleshoot the processing of BGP update-groups:
SUMMARY STEPS
1. enable
2. debug ip bgp groups [index-group | ip-address]
DETAILED STEPS
Displaying BGP Update-Group Statistics
Perform this task to display BGP update-group statistics:
SUMMARY STEPS
1. enable
2. show ip bgp replication [index-group | ip-address]
DETAILED STEPS
Displaying Information About the Processing of BGP Update-Groups
Perform this task to display information related to the processing of BGP update-groups.
SUMMARY STEPS
1. enable
2. show ip bgp update-group [index-group | ip-address] [summary]
DETAILED STEPS
Configuration Examples for BGP Dynamic Update Peer-Groups
The following examples illustrate the configuration and verification of this feature:
•Clearing BGP Update-Group Member Sessions: Example
•Troubleshooting the Processing of BGP Update-Groups: Example
•Displaying BGP Update-Group Statistics: Example
•Displaying Information About the Processing of BGP Update Groups: Example
Clearing BGP Update-Group Member Sessions: Example
The following example clears the membership of neighbor 10.0.0.1 from an update-group:
Router#
clear ip bgp update-group 10.0.0.1Troubleshooting the Processing of BGP Update-Groups: Example
The following example output from the debug ip bgp groups command shows the recalculation of update-groups after the clear ip bgp groups command was issued:
Router# debug ip bgp groups
5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.5 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.5 flags 0x0 cap 0x0 and updgrp 2 fl05w4d: BGP-DYN(0): Update-group 2 flags 0x0 cap 0x0 policies same as 10.4.9.5 fl05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.8 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.8 flags 0x0 cap 0x0 and updgrp 2 fl05w4d: BGP-DYN(0): Update-group 2 flags 0x0 cap 0x0 policies same as 10.4.9.8 fl05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.21 Down User reset5w4d: BGP-DYN(0): Comparing neighbor 10.4.9.21 flags 0x0 cap 0x0 and updgrp 1 f05w4d: BGP-DYN(0): Update-group 1 flags 0x0 cap 0x0 policies same as 10.4.9.21 f05w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.5 Up5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.21 Up5w4d: %BGP-5-ADJCHANGE: neighbor 10.4.9.8 UpDisplaying BGP Update-Group Statistics: Example
The following sample output from the show ip bgp replication command shows update-group replication information for all for neighbors:
Router# show ip bgp replicationBGP Total Messages Formatted/Enqueued : 0/0Index Type Members Leader MsgFmt MsgRepl Csize Qsize1 internal 1 10.4.9.21 0 0 0 02 internal 2 10.4.9.5 0 0 0 0
Displaying Information About the Processing of BGP Update Groups: Example
The following sample output from the show ip bgp update-group command shows update-group information for all neighbors:
Router# show ip bgp update-groupBGP version 4 update-group 1, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Route map for outgoing advertisements is COST1Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 1 member:10.4.9.21BGP version 4 update-group 2, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 2 members:10.4.9.5 10.4.9.8
Where to Go Next
For information about the BGP Configuration Using Peer Templates feature, refer to the BGP Configuration Using Peer Templates document.
Additional References
The following sections provide references related to the BGP Dynamic Update Peer-Group feature.
Related Documents
Related Topic Document TitleBGP commands
Cisco IOS Release 12.0 Network Protocols Command Reference, Part 1
Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols, Release 12.2
Cisco IOS IP Command Reference, Volume 2 of 4: Routing Protocols, Release 12.3T
BGP configuration tasks
Cisco IOS Release 12.0 Network Protocols Configuration Guide, Part 1
Cisco IOS IP Configuration Guide, Release 12.3T
BGP peer template configuration tasks
Standards
Standards TitleNo new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
RFCs TitleNo new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents new commands only.
New Commands
clear ip bgp update-group
To reset Border Gateway Protocol (BGP) connections for all the members of a BGP update group, use the clear ip bgp update-group command in privileged EXEC mode.
Syntax Without Address Family Syntax
clear ip bgp update-group [index-group | neighbor-address]
Syntax With Address Family Syntax
clear ip bgp [all | ipv4 {multicast | mdt | unicast} | ipv6 {multicast | unicast} | vpnv4 unicast | vpnv6 unicast] update-group [index-group | neighbor-address]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear ip bgp update-group command is used to clear BGP update group member sessions. If no keywords or arguments are specified, entering this command will recalculate all update groups. Specific index numbers for update groups and information about update-group membership is displayed in the output of the show ip bgp update-group and debug ip bgp groups commands.
When a change to outbound policy occurs, the BGP routing process will automatically recalculate update-group memberships and apply changes by triggering an outbound soft reset after a 1-minute timer expires. This behavior is designed to provide the network operator with time to change the configuration before the soft reset is initiated. You can immediately initiate the outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command or immediately initiate a hard reset by entering the clear ip bgp ip-address command.
Note In Cisco IOS Release 12.0(25)S, 12.3(2)T, and prior releases, the update group recalculation delay timer is set to 3 minutes.
Examples
In the following example, the membership of the 10.0.0.1 peer is cleared from an update group:
Router#
clear ip bgp update-group 10.0.0.1In the following example, update-group information for all peers in the index 1 update group is cleared:
Router#
clear ip bgp update-group 1In the following example, update-group information for all MDT address family session peers in the index 6 update group is cleared:
Router#
clear ip bgp ipv4 mdt update-group 6Related Commands
debug ip bgp updates
To display information about the processing of Border Gateway Protocol (BGP) updates, use the debug ip bgp updates command in privileged EXEC mode. To disable the display of BGP update information, use the no form of this command.
debug ip bgp updates [access-list | expanded-access-list] [in | out] [events]
no debug ip bgp updates [access-list | expanded-access-list] [in | out] [events]
Syntax Description
Command Modes
Privileged EXEC
Command History
Examples
In the following sample output, the output shows that the BGP session was cleared between neighbor 10.4.9.21 and the local router 10.4.9.4. There are no field description tables for this command because the debugging output from this command depends on the subsequent commands that are entered.
Router# debug ip bgp updates5w2d: %SYS-5-CONFIG_I: Configured from console by console5w2d: BGP: 10.4.9.21 went from Idle to Active5w2d: BGP: 10.4.9.21 open active, delay 7032ms5w2d: BGP: 10.4.9.21 open active, local address 10.4.9.45w2d: BGP: 10.4.9.21 went from Active to OpenSent5w2d: BGP: 10.4.9.21 sending OPEN, version 4, my as: 1015w2d: BGP: 10.4.9.21 send message type 1, length (incl. header) 455w2d: BGP: 10.4.9.21 rcv message type 1, length (excl. header) 265w2d: BGP: 10.4.9.21 rcv OPEN, version 45w2d: BGP: 10.4.9.21 rcv OPEN w/ OPTION parameter len: 165w2d: BGP: 10.4.9.21 rcvd OPEN w/ optional parameter type 2 (Capability) len 65w2d: BGP: 10.4.9.21 OPEN has CAPABILITY code: 1, length 45w2d: BGP: 10.4.9.21 OPEN has MP_EXT CAP for afi/safi: 1/15w2d: BGP: 10.4.9.21 rcvd OPEN w/ optional parameter type 2 (Capability) len 25w2d: BGP: 10.4.9.21 OPEN has CAPABILITY code: 128, length 05w2d: BGP: 10.4.9.21 OPEN has ROUTE-REFRESH capability(old) for all address-fams5w2d: BGP: 10.4.9.21 rcvd OPEN w/ optional parameter type 2 (Capability) len 25w2d: BGP: 10.4.9.21 OPEN has CAPABILITY code: 2, length 05w2d: BGP: 10.4.9.21 OPEN has ROUTE-REFRESH capability for all address-families5w2d: BGP: 10.4.9.21 went from OpenSent to OpenConfirm5w2d: BGP: 10.4.9.21 went from OpenConfirm to Established5w2d: %BGP-5-ADJCHANGE: neighbor 10.4.9.21 Up5w2d: BGP(0): 10.4.9.21 computing updates, afi 0, neighbor version 0, table ver05w2d: BGP(0): 10.4.9.21 update run completed, afi 0, ran for 0ms, neighbor vers15w2d: BGP(0): 10.4.9.21 initial update completedIn the following sample, the output shows that the local router is sending updates with the cost community:
Router# debug ip bgp updates out*Mar 15 01:41:23.515:BGP(0):10.0.0.5 computing updates, afi 0, neighbor version 0, table version 64, starting at 0.0.0.0*Mar 15 01:41:23.515:BGP(0):10.0.0.5 send UPDATE (format) 0.0.0.0/0, next 10.0.0.2, metric 0, path , extended community Cost:igp:1:100*Mar 15 01:41:23.515:BGP(0):10.0.0.5 send UPDATE (format) 10.2.2.0/24, next 10.20.20.10, metric 0, path 10, extended community Cost:igp:8:22*Mar 15 01:41:23.515:BGP(0):10.0.0.5 send UPDATE (format) 10.13.13.0/24, next 10.0.0.8, metric 0, pathIn the following sample, the output shows that the local router is receiving updates with the cost community:
Router# debug ip bgp updates in*Jan 6 01:27:09.111:BGP(2):10.0.0.8 rcvd UPDATE w/ attr:nexthop 10.0.0.8, origin ?, localpref 100, metric 0, path 10, extended community RT:100:1 Cost:igp:10:10 Cost:igp:11:11show ip bgp update-group
To display information about BGP update groups, use the show ip bgp update-group command in user EXEC or privileged EXEC mode.
show ip bgp update-group [index-group | ip-address] [summary]
Syntax Description
Command Modes
User EXEC
Privileged EXECCommand History
Usage Guidelines
Use this command to display information about BGP update groups. When a change to BGP outbound policy occurs, the router automatically recalculates update group memberships and applies the changes by triggering an outbound soft reset after a 1-minute timer expires. This behavior is designed to provide the network operator with time to change the configuration if a mistake is made. You can manually enable an outbound soft reset before the timer expires by entering the clear ip bgp ip-address soft out command.
Note In Cisco IOS Release 12.0(25)S, 12.3(2)T, and prior releases the update group recalculation delay timer is set to 3 minutes.
Examples
The following sample output from the show ip bgp update-group command shows update group information for all neighbors:
Router# show ip bgp update-groupBGP version 4 update-group 1, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Route map for outgoing advertisements is COST1Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 1 member:10.4.9.21BGP version 4 update-group 2, internal, Address Family: IPv4 UnicastBGP Update version : 0, messages 0/0Update messages formatted 0, replicated 0Number of NLRIs in the update sent: max 0, min 0Minimum time between advertisement runs is 5 secondsHas 2 members:10.4.9.5 10.4.9.8Table 1 describes the significant fields shown in the display.
The following sample output from the show ip bgp update-group command shows a summary of update-group information for the 10.4.9.8 neighbor:
Router# show ip bgp update-group 10.4.9.8 summary
Summary for Update-group 2 :------------------------------BGP router identifier 10.4.9.4, local AS number 101BGP table version is 1, main routing table version 1Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd10.4.9.5 4 101 35 35 1 0 0 00:26:22 010.4.9.8 4 101 39 39 1 0 0 00:26:21 0Table 2 describes the significant fields shown in the display.
Related Commands
Glossary
dynamic peer-group—Another name for an update-group.
peer-group—A group of neighbors, calculated at configuration time, that share the same outbound policies and can be replicated in the same updates.
peer-policy template—Peer policy templates are used to used group and apply the configuration of commands that are applied within specific address-families and NLRI configuration mode.
peer-session template—Peer session templates are used to group and apply the configuration of general session commands that are common to all address-family and Network Layer Reachability Information (NLRI) configuration modes.
peer-template—A configuration pattern that can be applied to neighbors that share common policies. Peer templates are reusable and support inheritance, allowing the network operator to group and apply distinct neighbor configurations for BGP neighbors that share common policies, and define very complex configuration patterns through the ability of a peer template to inherit configurations from other peer templates. There are two types of peer templates: "policy-templates" and "session-templates."
update-group—Like a peer-group, an update-group is a group of neighbors, calculated at configuration time, that share the same outbound policies and can be replicated in the same updates. However, update-groups are calculated dynamically and are not restricted by outbound policies.
Note Refer to Internetworking Terms and Acronyms for terms not included in this glossary.
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