- Cisco IOS NetFlow Overview
- Getting Started with Configuring Cisco IOS NetFlow and NetFlow Data Export
- Configuring NetFlow and NetFlow Data Export
- Configuring NetFlow Aggregation Caches
- Using NetFlow Filtering or Sampling to Select the Network Traffic to Track
- Configuring NetFlow BGP Next Hop Support for Accounting and Analysis
- Configuring MPLS Egress NetFlow Accounting and Analysis
- Configuring MPLS-aware NetFlow
- Configuring NetFlow Multicast Accounting
- Configuring SNMP and using the NetFlow MIB to Monitor NetFlow Data
- Configuring NetFlow Top Talkers using Cisco IOS CLI Commands or SNMP Commands
- NetFlow Layer 2 and Security Monitoring Exports
- NetFlow Reliable Export With SCTP
- Detecting and Analyzing Network Threats With NetFlow
- Index
Contents
- Getting Started with Configuring Cisco IOS NetFlow and NetFlow Data Export
- Finding Feature Information
- Prerequisites for Configuring NetFlow and NetFlow Data Export
- Restrictions for Configuring NetFlow and NetFlow Data Export
- NetFlow Data Capture
- NetFlow Data Export
- Information About Configuring NetFlow and NetFlow Data Export
- NetFlow Data Capture
- NetFlow Flows Key Fields
- NetFlow Data Export Using the Version 9 Export Format
- How to Configure NetFlow and NetFlow Data Export
- Configuring NetFlow and NetFlow Data Export Using the Version 9 Export Format
- Verifying That NetFlow Is Operational and View NetFlow Statistics
- Verifying That NetFlow Data Export Is Operational
- Configuration Examples for Configuring NetFlow and NetFlow Data Export
- Example Configuring Egress NetFlow Accounting
- Example Configuring NetFlow Subinterface Support
- Example Configuring NetFlow Multiple Export Destinations
- Example Configuring NetFlow and NetFlow Data Export Using the Version 9 Export Format
- Example Configuring NetFlow for Analyzing PPPoE Session Traffic
- Additional References
- Feature Information for Configuring NetFlow and NetFlow Data Export
- Glossary
Getting Started with Configuring Cisco IOS NetFlow and NetFlow Data Export
This module contains the minimum amount of information about and instructions necessary for configuring NetFlow to capture and export network traffic data. This module is intended to help you get started using NetFlow and NetFlow Data Export as quickly as possible. If you want more detailed information about this feature and instructions for configuring NetFlow and NetFlow Data Export, please refer to Configuring NetFlow and NetFlow Data Export.
NetFlow capture and export are performed independently on each internetworking device on which NetFlow is enabled. NetFlow need not be operational on each router in the network.
NetFlow is a Cisco IOS application that provides statistics on packets flowing through the router. NetFlow is emerging as a primary network accounting and security technology.
- Finding Feature Information
- Prerequisites for Configuring NetFlow and NetFlow Data Export
- Restrictions for Configuring NetFlow and NetFlow Data Export
- Information About Configuring NetFlow and NetFlow Data Export
- How to Configure NetFlow and NetFlow Data Export
- Configuration Examples for Configuring NetFlow and NetFlow Data Export
- Additional References
- Feature Information for Configuring NetFlow and NetFlow Data Export
- 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 at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Configuring NetFlow and NetFlow Data Export
Before you enable NetFlow:
Configure the router for IP routing.
Ensure that one of the following is enabled on your router, and on the interfaces that you want to configure NetFlow on: Cisco Express Forwarding (CEF), distributed CEF, or fast switching.
Understand the resources required on your router because NetFlow consumes additional memory and CPU resources.
Restrictions for Configuring NetFlow and NetFlow Data Export
NetFlow Data Capture
NetFlow consumes additional memory. If you have memory constraints, you might want to preset the size of the NetFlow cache so that it contains a smaller number of entries. The default cache size depends on the platform. For example, the default cache size for the Cisco 7500 router is 65536 (64K) entries.
Memory Impact
During times of heavy traffic, the additional flows can fill up the global flow hash table. If you need to increase the size of the global flow hash table, increase the memory of the router.
Cisco IOS Releases 12.2(14)S, 12.0(22)S, or 12.2(15)T
If your router is running a version of Cisco IOS prior to releases 12.2(14)S, 12.0(22)S, or 12.2(15)T, the ip route-cache flow command is used to enable NetFlow on an interface.
If your router is running Cisco IOS release 12.2(14)S, 12.0(22)S, 12.2(15)T, or later, the ip flow ingress command is used to enable NetFlow on an interface.
Egress NetFlow Accounting in Cisco IOS 12.3T Releases, 12.3(11)T, or Later
The Egress NetFlow Accounting feature captures NetFlow statistics for IP traffic only. MPLS statistics are not captured. The MPLS Egress NetFlow Accounting feature can be used on a provider edge (PE) router to capture IP traffic flow information for egress IP packets that arrived at the router as MPLS packets and underwent label disposition.
Egress NetFlow accounting might adversely affect network performance because of the additional accounting-related computation that occurs in the traffic-forwarding path of the router.
Locally generated traffic (traffic that is generated by the router on which the Egress NetFlow Accounting feature is configured) is not counted as flow traffic for the Egress NetFlow Accounting feature.
 Note | In Cisco IOS 12.2S releases, egress NetFlow captures either IPv4 packets or MPLS packets as they leave the router. |
The Egress NetFlow Accounting feature counts CEF-switched packets only. Process-switched transit packets are not counted.
NetFlow Data Export
Restrictions for NetFlow Version 9 Data Export
Backward compatibility--Version 9 is not backward-compatible with Version 5 or Version 8. If you need Version 5 or Version 8, you must configure it.
Export bandwidth--Export bandwidth use increases for Version 9 (because of template flowsets) versus Version 5. The increase in bandwidth usage versus Version 5 varies with the frequency with which template flowsets are sent. The default is to resend templates every 20 packets, which has a bandwidth cost of about 4 percent. If necessary, you can lower the resend rate with the ip flow-export template refresh-rate packets command.
Performance impact--Version 9 slightly decreases overall performance, because generating and maintaining valid template flowsets require additional processing.
Information About Configuring NetFlow and NetFlow Data Export
NetFlow Data Capture
NetFlow captures data from ingress (incoming) and egress (outgoing) packets. NetFlow gathers statistics for the following ingress IP packets:
IP-to-IP packets
IP-to-Multiprotocol Label Switching (MPLS) packets
Frame Relay-terminated packets
ATM-terminated packets
NetFlow captures data for all egress (outgoing) packets through the use of the following features:
Egress NetFlow Accounting--NetFlow gathers statistics for all egress packets for IP traffic only.
NetFlow MPLS Egress--NetFlow gathers statistics for all egress MPLS-to-IP packets.
NetFlow Flows Key Fields
A network flow is identified as a unidirectional stream of packets between a given source and destination--both are defined by a network-layer IP address and by transport-layer source and destination port numbers. Specifically, a flow is identified as the combination of the following key fields:
Source IP address
Destination IP address
Source port number
Destination port number
Layer 3 protocol type
Type of service (ToS)
Input logical interface
These seven key fields define a unique flow. If a packet has one key field different from another packet, it is considered to belong to another flow. A flow might contain other accounting fields (such as the AS number in the NetFlow export Version 5 flow format) that depend on the export record version that you configure. Flows are stored in the NetFlow cache.
NetFlow Data Export Using the Version 9 Export Format
NetFlow Data Export format Version 9 is a flexible and extensible format, which provides the versatility needed for support of new fields and record types. This format accommodates new NetFlow-supported technologies such as Multicast, Multiprotocol Label Switching (MPLS), and Border Gateway Protocol (BGP) next hop. The Version 9 export format enables you to use the same version for main and aggregation caches, and the format is extendable, so you can use the same export format with future features.
How to Configure NetFlow and NetFlow Data Export
- Configuring NetFlow and NetFlow Data Export Using the Version 9 Export Format
- Verifying That NetFlow Is Operational and View NetFlow Statistics
- Verifying That NetFlow Data Export Is Operational
Configuring NetFlow and NetFlow Data Export Using the Version 9 Export Format
Perform this task to configure NetFlow and NetFlow Data Export using the Version 9 export format.
1.
enable
2.
configure
terminal
3.
ip
flow-export
destination
{ip-address |
hostname}
udp-port
4. Repeat Step 3 once to configure a second NetFlow export destination.
5.
ip
flow-export
version
9
6.
interface
interface-type
interface-number
7.
ip
flow
{ingress |
egress}
8.
exit
9. Repeat Steps 6 through 8 to enable NetFlow on other interfaces
10.
end
DETAILED STEPS
Verifying That NetFlow Is Operational and View NetFlow Statistics
To verify that NetFlow is working properly, perform this optional task.
1.
show
ip
flow
interface
2.
show
ip
cache
flow
3.
show
ip
cache
verbose
flow
DETAILED STEPS
| Step 1 |
show
ip
flow
interface
Use this command to display the NetFlow configuration for an interface. The following is sample output from this command: Example: Router# show ip flow interface Ethernet0/0 ip flow ingress |
| Step 2 |
show
ip
cache
flow
Use this command to verify that NetFlow is operational and to display a summary of the NetFlow statistics. The following is sample output from this command: Example:
Router# show ip cache flow
IP packet size distribution (1103746 total packets):
1-32 64 96 128 160 192 224 256 288 320 352 384 416 448 480
.249 .694 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000
512 544 576 1024 1536 2048 2560 3072 3584 4096 4608
.000 .000 .027 .000 .027 .000 .000 .000 .000 .000 .000
IP Flow Switching Cache, 278544 bytes
35 active, 4061 inactive, 980 added
2921778 ager polls, 0 flow alloc failures
Active flows timeout in 30 minutes
Inactive flows timeout in 15 seconds
IP Sub Flow Cache, 21640 bytes
0 active, 1024 inactive, 0 added, 0 added to flow
0 alloc failures, 0 force free
1 chunk, 1 chunk added
last clearing of statistics never
Protocol Total Flows Packets Bytes Packets Active(Sec) Idle(Sec)
-------- Flows /Sec /Flow /Pkt /Sec /Flow /Flow
TCP-FTP 108 0.0 1133 40 2.4 1799.6 0.9
TCP-FTPD 108 0.0 1133 40 2.4 1799.6 0.9
TCP-WWW 54 0.0 1133 40 1.2 1799.6 0.8
TCP-SMTP 54 0.0 1133 40 1.2 1799.6 0.8
TCP-BGP 27 0.0 1133 40 0.6 1799.6 0.7
TCP-NNTP 27 0.0 1133 40 0.6 1799.6 0.7
TCP-other 297 0.0 1133 40 6.8 1799.7 0.8
UDP-TFTP 27 0.0 1133 28 0.6 1799.6 1.0
UDP-other 108 0.0 1417 28 3.1 1799.6 0.9
ICMP 135 0.0 1133 427 3.1 1799.6 0.8
Total: 945 0.0 1166 91 22.4 1799.6 0.8
SrcIf SrcIPaddress DstIf DstIPaddress Pr SrcP DstP Pkts
Et0/0 192.168.67.6 Et1/0.1 172.16.10.200 01 0000 0C01 51
Et0/0 10.10.18.1 Null 172.16.11.5 11 0043 0043 51
Et0/0 10.10.18.1 Null 172.16.11.5 11 0045 0045 51
Et0/0 10.234.53.1 Et1/0.1 172.16.10.2 01 0000 0800 51
Et0/0 10.10.19.1 Null 172.16.11.6 11 0044 0044 51
Et0/0 10.10.19.1 Null 172.16.11.6 11 00A2 00A2 51
Et0/0 192.168.87.200 Et1/0.1 172.16.10.2 06 0014 0014 50
Et0/0 192.168.87.200 Et1/0.1 172.16.10.2 06 0015 0015 52
.
.
.
Et0/0 172.16.1.84 Et1/0.1 172.16.10.19 06 0087 0087 50
Et0/0 172.16.1.84 Et1/0.1 172.16.10.19 06 0050 0050 51
Et0/0 172.16.1.85 Et1/0.1 172.16.10.20 06 0089 0089 49
Et0/0 172.16.1.85 Et1/0.1 172.16.10.20 06 0050 0050 50
Et0/0 10.251.10.1 Et1/0.1 172.16.10.2 01 0000 0800 51
Et0/0 10.162.37.71 Null 172.16.11.3 06 027C 027C 49
|
| Step 3 |
show
ip
cache
verbose
flow
Use this command to verify that NetFlow is operational and to display a detailed summary of the NetFlow statistics. The following is sample output from this command: Example:
Router# show ip cache verbose flow
IP packet size distribution (1130681 total packets):
1-32 64 96 128 160 192 224 256 288 320 352 384 416 448 480
.249 .694 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000
512 544 576 1024 1536 2048 2560 3072 3584 4096 4608
.000 .000 .027 .000 .027 .000 .000 .000 .000 .000 .000
IP Flow Switching Cache, 278544 bytes
35 active, 4061 inactive, 980 added
2992518 ager polls, 0 flow alloc failures
Active flows timeout in 30 minutes
Inactive flows timeout in 15 seconds
IP Sub Flow Cache, 21640 bytes
0 active, 1024 inactive, 0 added, 0 added to flow
0 alloc failures, 0 force free
1 chunk, 1 chunk added
last clearing of statistics never
Protocol Total Flows Packets Bytes Packets Active(Sec) Idle(Sec)
-------- Flows /Sec /Flow /Pkt /Sec /Flow /Flow
TCP-FTP 108 0.0 1133 40 2.4 1799.6 0.9
TCP-FTPD 108 0.0 1133 40 2.4 1799.6 0.9
TCP-WWW 54 0.0 1133 40 1.2 1799.6 0.8
TCP-SMTP 54 0.0 1133 40 1.2 1799.6 0.8
TCP-BGP 27 0.0 1133 40 0.6 1799.6 0.7
TCP-NNTP 27 0.0 1133 40 0.6 1799.6 0.7
TCP-other 297 0.0 1133 40 6.6 1799.7 0.8
UDP-TFTP 27 0.0 1133 28 0.6 1799.6 1.0
UDP-other 108 0.0 1417 28 3.0 1799.6 0.9
ICMP 135 0.0 1133 427 3.0 1799.6 0.8
Total: 945 0.0 1166 91 21.9 1799.6 0.8
SrcIf SrcIPaddress DstIf DstIPaddress Pr TOS Flgs Pkts
Port Msk AS Port Msk AS NextHop B/Pk Active
Et0/0 192.168.67.6 Et1/0.1 172.16.10.200 01 00 10 799
0000 /0 0 0C01 /0 0 0.0.0.0 28 1258.1
Et0/0 10.10.18.1 Null 172.16.11.5 11 00 10 799
0043 /0 0 0043 /0 0 0.0.0.0 28 1258.0
Et0/0 10.10.18.1 Null 172.16.11.5 11 00 10 799
0045 /0 0 0045 /0 0 0.0.0.0 28 1258.0
Et0/0 10.234.53.1 Et1/0.1 172.16.10.2 01 00 10 799
0000 /0 0 0800 /0 0 0.0.0.0 28 1258.1
Et0/0 10.10.19.1 Null 172.16.11.6 11 00 10 799
0044 /0 0 0044 /0 0 0.0.0.0 28 1258.1
.
.
.
Et0/0 172.16.1.84 Et1/0.1 172.16.10.19 06 00 00 799
0087 /0 0 0087 /0 0 0.0.0.0 40 1258.1
Et0/0 172.16.1.84 Et1/0.1 172.16.10.19 06 00 00 799
0050 /0 0 0050 /0 0 0.0.0.0 40 1258.0
Et0/0 172.16.1.85 Et1/0.1 172.16.10.20 06 00 00 798
0089 /0 0 0089 /0 0 0.0.0.0 40 1256.5
Et0/0 172.16.1.85 Et1/0.1 172.16.10.20 06 00 00 799
0050 /0 0 0050 /0 0 0.0.0.0 40 1258.0
Et0/0 10.251.10.1 Et1/0.1 172.16.10.2 01 00 10 799
0000 /0 0 0800 /0 0 0.0.0.0 1500 1258.1
Et0/0 10.162.37.71 Null 172.16.11.3 06 00 00 798
027C /0 0 027C /0 0 0.0.0.0 40 1256.4
|
Verifying That NetFlow Data Export Is Operational
To verify that NetFlow data export is operational and to view the statistics for NetFlow data export perform the step in this optional task.
1.
show
ip
flow
export
DETAILED STEPS
Use this command to display the statistics for the NetFlow data export, including statistics for the main cache and for all other enabled caches. The following is sample output from this command: Example: Router# show ip flow export Flow export v9 is enabled for main cache Exporting flows to 172.16.10.2 (99) Exporting using source interface Ethernet0/0 Version 9 flow records 0 flows exported in 0 udp datagrams 0 flows failed due to lack of export packet 0 export packets were sent up to process level 0 export packets were dropped due to no fib 0 export packets were dropped due to adjacency issues 0 export packets were dropped due to fragmentation failures 0 export packets were dropped due to encapsulation fixup failures |
Configuration Examples for Configuring NetFlow and NetFlow Data Export
- Example Configuring Egress NetFlow Accounting
- Example Configuring NetFlow Subinterface Support
- Example Configuring NetFlow Multiple Export Destinations
- Example Configuring NetFlow and NetFlow Data Export Using the Version 9 Export Format
- Example Configuring NetFlow for Analyzing PPPoE Session Traffic
Example Configuring Egress NetFlow Accounting
The following example shows how to configure Egress NetFlow Accounting:
configure terminal ! interface ethernet 0/0 ip flow egress !
Example Configuring NetFlow Subinterface Support
NetFlow Subinterface Support For Ingress (Received) Traffic On a Subinterface
configure terminal ! interface ethernet 0/0.1 ip flow ingress !
NetFlow SubInterface Support For Egress (Transmitted) Traffic On a Subinterface
configure terminal ! interface ethernet 1/0.1 ip flow egress !
Note | NetFlow performs additional checks for the status of each subinterface that requires more CPU processing time and bandwidth. If you have several subinterfaces configured and you want to configure NetFlow data capture on all of them, we recommend that you configure NetFlow on the main interface instead of on the individual subinterfaces. |
Example Configuring NetFlow Multiple Export Destinations
The following example shows how to configure NetFlow multiple export destinations:
configure terminal ! ip flow-export destination 10.10.10.10 9991 ip flow-export destination 172.16.10.2 9991 !
Note | You can configure a maximum of two export destinations for the main cache and for each aggregation cache. |
Example Configuring NetFlow and NetFlow Data Export Using the Version 9 Export Format
The following example shows how to configure NetFlow and NetFlow data export using the Version 9 export format:
configure terminal ! ip flow-export destination 10.10.10.10 9991 ip flow-export version 9 !
Example Configuring NetFlow for Analyzing PPPoE Session Traffic
If you want to obtain accurate NetFlow traffic statistics for PPPoE sessions, you must configure NetFlow on the virtual-template interface, not on the physical interface that is configured with VLAN encapsulation. For example, if you configure NetFlow on the physical interface that is configured for VLAN encapsulation as shown in the following configuration, the NetFlow traffic statistics will not be an accurate representation of the traffic on the PPPoE sessions.
! interface GigabitEthernet2/0/0.10 encapsulation dot1Q 10 ip flow egress pppoe enable
The following example shows how to configure egress NetFlow on a virtual template interface so that you can accurately analyze the packet size distribution statistics of the traffic that the router is sending to the end user over the PPoE session:
interface Virtual-Template 1 ip unnumbered ethernet 0 encapsulation ppp ip flow egress
The following display output from the show ip cache flow command shows that this PPPoE session traffic is comprised primarily of 1536-byte packets.
Router# show ip cache flow IP packet size distribution (11014160 total packets): 1-32 64 96 128 160 192 224 256 288 320 352 384 416 448 480 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 .000 512 544 576 1024 1536 2048 2560 3072 3584 4096 4608 .000 .000 .000 .000 .999 .000 .000 .000 .000 .000 .000
Additional References
Related Documents
|
Related Topic |
Document Title |
|---|---|
|
Cisco IOS commands |
|
|
Overview of Cisco IOS NetFlow |
Cisco IOS NetFlow Overview |
|
Tasks for configuring NetFlow to capture and export network traffic data |
Configuring NetFlow and NetFlow Data Export |
|
Tasks for configuring Configuring MPLS Aware NetFlow |
Configuring MPLS Aware NetFlow |
|
Tasks for configuring MPLS egress NetFlow accounting |
Configuring MPLS Egress NetFlow Accounting and Analysis |
|
Tasks for configuring NetFlow input filters |
Using NetFlow Filtering or Sampling to Select the Network Traffic to Track |
|
Tasks for configuring random sampled NetFlow |
Using NetFlow Filtering or Sampling to Select the Network Traffic to Track |
|
Tasks for configuring NetFlow aggregation caches |
Configuring NetFlow Aggregation Caches |
|
Tasks for configuring NetFlow BGP next hop support |
Configuring NetFlow BGP Next Hop Support for Accounting and Analysis |
|
Tasks for configuring NetFlow multicast support |
Configuring NetFlow Multicast Accounting |
|
Tasks for detecting and analyzing network threats with NetFlow |
Detecting and Analyzing Network Threats With NetFlow |
|
Tasks for configuring NetFlow Reliable Export With SCTP |
NetFlow Reliable Export With SCTP |
|
Tasks for configuring NetFlow Layer 2 and Security Monitoring Exports |
NetFlow Layer 2 and Security Monitoring Exports |
|
Tasks for configuring the SNMP NetFlow MIB |
Configuring SNMP and using the NetFlow MIB to Monitor NetFlow Data |
|
Tasks for configuring the NetFlow MIB and Top Talkers feature |
Configuring NetFlow Top Talkers using Cisco IOS CLI Commands or SNMP Commands |
|
Information for installing, starting, and configuring the CNS NetFlow Collection Engine |
|
|
Configuration commands for NetFlow |
Cisco IOS NetFlow Command Reference |
Standards
|
Standards |
Title |
|---|---|
|
No new or modified standards are supported , and support for existing standards has not been modified. |
-- |
MIBs
|
MIBs |
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: |
RFCs
|
RFCs |
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. |
Feature Information for Configuring NetFlow and NetFlow Data Export
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 Configuration Information |
|---|---|---|
|
Egress NetFlow Accounting |
12.3(11)T 15.0(1)S |
The Egress NetFlow Accounting feature allows NetFlow statistics to be gathered on egress traffic that is exiting the router. Previous versions of NetFlow allow statistics to be gathered only on ingress traffic that is entering the router. The following commands were introduced by this feature: ip flow egress and ip flow-egress input-interface. The following commands were modified by this feature: flow-sampler, match, show ip cache flow, show ip cache verbose flow, and show ip flow interface. |
|
NetFlow Multiple Export Destinations |
12.0(19)S 12.2(2)T 12.2(14)S 15.0(1)S |
The NetFlow Multiple Export Destinations feature enables configuration of multiple destinations of the NetFlow data. The following commands were modified by this feature: ip flow-aggregation cache, ip flow-export destination, and show ip flow export. |
|
NetFlow Subinterface Support |
12.0(22)S 12.2(14)S 12.2(15)T |
The NetFlow Subinterface Support feature provides the ability to enable NetFlow on a per-subinterface basis. The following command was introduced by this feature: ip flow ingress. The following command was modified by this feature: show ip interface. |
|
NetFlow v9 Export Format |
12.0(24)S 12.2(18)S 12.2(27)SBC 12.2(18)SXF 12.3(1) 15.0(1)S |
The NetFlow v9 Export Format is flexible and extensible, which provides the versatility needed to support new fields and record types. This format accommodates new NetFlow-supported technologies such as Multicast, MPLS, NAT, and BGP next hop. The following commands were modified by this feature: debug ip flow export, export, ip flow-export, and show ip flow export. |
Glossary
AS --autonomous system. A collection of networks under a common administration sharing a common routing strategy. Autonomous systems are subdivided by areas. An autonomous system must be assigned a unique 16-bit number by the Internet Assigned Numbers Authority (IANA).
CEF --Cisco Express Forwarding. Layer 3 IP switching technology that optimizes network performance and scalability for networks with large and dynamic traffic patterns.
BGP --Border Gateway Protocol. An interdomain routing protocol that replaces Exterior Gateway Protocol (EGP). A BGP system exchanges reachability information with other BGP systems. BGP is defined by RFC 1163.
BGP next hop --IP address of the next hop to be used by a router to reach a certain destination.
dCEF --distributed Cisco Express Forwarding. A type of CEF switching in which line cards (such as Versatile Interface Processor (VIP) line cards) maintain identical copies of the forwarding information base (FIB) and adjacency tables. The line cards perform the express forwarding between port adapters; this relieves the Route Switch Processor of involvement in the switching operation.
export packet --Type of packet built by a device (for example, a router) with NetFlow services enabled that is addressed to another device (for example, the NetFlow Collection Engine). The packet contains NetFlow statistics. The other device processes the packet (parses, aggregates, and stores information on IP flows).
fast switching --Cisco feature in which a route cache is used to expedite packet switching through a router.
flow --A set of packets with the same source IP address, destination IP address, protocol, source/destination ports, and type-of-service, and the same interface on which the flow is monitored. Ingress flows are associated with the input interface, and egress flows are associated with the output interface.
MPLS --Multiprotocol Label Switching. An emerging industry standard for the forwarding of packets along a normally routed path (sometimes called MPLS hop-by-hop forwarding).
NetFlow --A Cisco IOS application that provides statistics on packets flowing through the router. It is emerging as a primary network accounting and security technology.
NetFlow Aggregation --A NetFlow feature that lets you summarize NetFlow export data on an IOS router before the data is exported to a NetFlow data collection system such as the NetFlow Collection Engine. This feature lowers bandwidth requirements for NetFlow export data and reduces platform requirements for NetFlow data collection devices.
NetFlow Collection Engine (formerly NetFlow FlowCollector)--Cisco application that is used with NetFlow on Cisco routers and Catalyst series switches. The NetFlow Collection Engine collects packets from the router that is running NetFlow and decodes, aggregates, and stores them. You can generate reports on various aggregations that can be set up on the NetFlow Collection Engine.
NetFlow v9 --NetFlow export format Version 9. A flexible and extensible means for carrying NetFlow records from a network node to a collector. NetFlow Version 9 has definable record types and is self-describing for easier NetFlow Collection Engine configuration.
RP --Route Processor. A processor module in the Cisco 7000 series routers that contains the CPU, system software, and most of the memory components that are used in the router. Sometimes called a Supervisory Processor.