Table Of Contents
Prerequisites for NetFlow MPLS Aggregation
Restrictions for NetFlow MPLS Aggregation
Information About NetFlow MPLS Aggregation
How to Configure NetFlow MPLS Aggregation
Configuring NetFlow MPLS Aggregation
Verifying NetFlow MPLS Aggregation
Configuration Example for NetFlow MPLS Aggregation
Configuring NetFlow MPLS Aggregation: Example
ip flow-cache mpls label-positions
Feature Information for NetFlow MPLS Aggregation
NetFlow MPLS Aggregation
First Published: December 4th, 2006Last Updated: December 4th, 2006Cisco IOS NetFlow is a Cisco IOS application that provides statistics on packets flowing through a router. Cisco IOS NetFlow is the standard for acquiring IP operational data from IP networks. Cisco IOS NetFlow provides network and security monitoring, network planning, traffic analysis, and IP accounting.
The NetFlow MPLS Aggregation feature helps you configure a lightweight version of NetFlow that captures high-level Multi Protocol Label Switching (MPLS) provider edge-provider edge (PE-to-PE) Traffic statistics for your network. The phrase "MPLS PE-to-PE traffic statistics" is often abbreviated as "MPLS-PET".
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Contents
•Prerequisites for NetFlow MPLS Aggregation
•Restrictions for NetFlow MPLS Aggregation
•Information About NetFlow MPLS Aggregation
•How to Configure NetFlow MPLS Aggregation
•Configuration Example for NetFlow MPLS Aggregation
•Feature Information for NetFlow MPLS Aggregation
Prerequisites for NetFlow MPLS Aggregation
The following prerequisites must be met before you configure the NetFlow MPLS Aggregation feature:
•The router must be configured for IP routing.
•One of the following must be enabled on your router and on the interfaces on which you want to configure NetFlow: Cisco Express Forwarding (CEF) or distributed CEF.
Restrictions for NetFlow MPLS Aggregation
The following restrictions apply to configuring the NetFlow MPLS Aggregation feature:
•This feature is intended for use on an MPLS PE node.
•Cisco 10K—If you have egress NetFlow configured and you configure NetFlow MPLS Aggregation, the parallel express forwarding (PXF) is changed to MPLS-PET NetFlow, and all NetFlow egress records will become MPLS-PET egress NetFlow records.
•Cisco 10K—NetFlow will not capture actual MPLS labels in the aggregation cache. The value in the MPLS labels field will be set to zero.
•Cisco 10K—The MPLS-PET records go directly to the aggregation cache, bypassing the main cache.
Information About NetFlow MPLS Aggregation
The NetFlow MPLS Aggregation feature allows you to generate a PE-to-PE traffic matrix with a minimal impact on the processing capabilities of your router. The data captured by the NetFlow MPLS Aggregation feture is similar to the data captured by Traffic Matrix Statistics (TMS). Cisco has discontinued TMS support in 12.2S. If you want to generate a PE-to-PE traffic matrix on a router running Cisco IOS Release 12.2S, you must use the NetFlow MPLS Aggregation feature.
The NetFlow MPLS Aggregation feature limits the impact on the processing capabilities of your router because it requires only the following information from the traffic that is analyzed by NetFlow:
•The interface on which the flow traffic is received on
•The exit point of the flow traffic from the MPLS cloud, such as the BGP next hop
•EXP bits from the imposed MPLS top label post switching
•The packet and byte counts for the flow
How to Configure NetFlow MPLS Aggregation
The tasks in this section explain how to configure and verify the NetFlow MPLS Aggregation feature:
•Configuring NetFlow MPLS Aggregation
•Verifying NetFlow MPLS Aggregation
Configuring NetFlow MPLS Aggregation
SUMMARY STEPS
1. enable
2. configure terminal
3. ip flow-cache mpls label-positions [label-position-1 [label-position-2 [label-position-3]]] exp-bgp-prefix-fields
4. ip flow-export version 9 bgp-nexthop
5. ip flow-aggregation cache exp-bgp-prefix
6. export version 9
7. export destination {ip-address | hostname} port-number
8. enabled
9. exit
10. interface interface-number interface-type
11. ip flow {ingress | egress}
12. end
DETAILED STEPS
Verifying NetFlow MPLS Aggregation
SUMMARY STEPS
1. enable
2. show ip cache verbose flow aggregation exp-bgp-prefix
DETAILED STEPS
Step 1 enable
Enters privileged EXEC mode.
Router> enable
Step 2 show ip cache verbose flow aggregation exp-bgp-prefix
Displays the MPLS-PET traffic matrix from the exp-bgp-prefix aggregation cache.
Router# show ip cache verbose flow aggregation exp-bgp-prefix
IP Flow Switching Cache, 278544 bytes1 active, 4095 inactive, 4 added97 ager polls, 0 flow alloc failuresActive flows timeout in 30 minutesInactive flows timeout in 15 secondsIP Sub Flow Cache, 17032 bytes1 active, 1023 inactive, 4 added, 4 added to flow0 alloc failures, 0 force free1 chunk, 1 chunk addedSrc If BGP Nexthop Label MPLS EXP Flows Pkts B/Pk ActiveGi4/0/0.102 10.40.40.40 0 0 1 5 100 0.0
Configuration Example for NetFlow MPLS Aggregation
This section provides the following example for configuring the NetFlow MPLS Aggregation feature:
•Configuring NetFlow MPLS Aggregation: Example
Configuring NetFlow MPLS Aggregation: Example
The following example shows how to configure the NetFlow MPLS Aggregation feature.
This example uses the following parameters for the exp-bgp-prefix aggregation cache:
•Cache size: 2046
•Inactive timeout: 200 seconds
•Active timeout: 45 minutes
•Export destination IP address and UDP port number: 172.16.10.2 99
!ip flow-cache mpls label-positions 1 2 exp-bgp-prefix-fields!ip flow-export version 9 bgp-nexthop!ip flow-aggregation cache exp-bgp-prefix!export version 9export destination 172.16.10.2 99cache entries 2046cache timeout inactive 200cache timeout active 45enabledexitinterface fastethernet 2/1/2ip flow ingressend!Additional References
The following sections provide references related to the NetFlow MPLS Aggregation feature.
Related Documents
Related Topic Document TitleCisco IOS NetFlow configuration
Cisco IOS NetFlow Configuration Guide, Release 12.4
Cisco IOS NetFlow commands
Cisco IOS NetFlow Command Reference, Release 12.2SB
Standards
Standard TitleNo new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature
—
MIBs
RFCs
RFC 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 modified commands only.
•ip flow-cache mpls label-positions
ip flow-cache mpls label-positions
To enable Multiprotocol Label Switching (MPLS)-Aware NetFlow, use the ip flow-cache mpls label-positions command in global configuration mode. To disable MPLS-aware NetFlow, use the no form of this command.
ip flow-cache mpls label-positions [label-position-1 [label-position-2 [label-position-3]]] [[exp-bgp-prefix-fields] [no-ip-fields]] [mpls-length]
no ip flow-cache mpls label-positions
Syntax Description
Defaults
MPLS-Aware NetFlow is not enabled.
Command Modes
Global configuration
Command History
Usage Guidelines
You must have NetFlow accounting configured on your router before you can use this command.
Use this command to configure the NetFlow MPLS Aggregation feature on a label switch router (LSR) and to specify labels of interest in the incoming label stack. Label positions are counted from the top of the stack, starting with 1. The position of the top label is 1, the position of the second label is 2, and so forth.
With NetFlow MPLS Aggregation enabled on the router, NetFlow collects data for incoming IP packets and for incoming MPLS packets on all interfaces where NetFlow is enabled in full or in sampled mode.
Caution When you enter the ip flow-cache mpls label-positions command on a Cisco 12000 Series Internet Router, NetFlow will stop collecting data for incoming IP packets on any Engine 4P line cards installed in the router on which NetFlow is enabled in full or in sampled mode. Engine 4P line cards in a Cisco 12000 Series Internet Router do not support NetFlow data collection of incoming IP packets and MPLS packets concurrently.
Tip NetFlow MPLS Aggregation is enabled in global configuration mode. NetFlow is enabled per interface.
Examples
The following example shows how to configure NetFlow MPLS Aggregation to capture the first (top), third, and fifth label:
Router(config)# ip flow-cache mpls label-positions 1 3 5The following example shows how to configure NetFlow MPLS Aggregation to capture only MPLS flow information (no IP-related flow fields) and the length that represents the sum of the MPLS packet payload length and the MPLS label stack length:
Router(config)# ip flow-cache mpls label-positions no-ip-fields mpls-lengthThe following example shows how to configure MPLS PE-to-PE Traffic Statistics for Netflow:
Router(config)# ip flow-cache mpls label-positions 1 2 exp-bgp-prefix-fieldsRelated Commands
Feature Information for NetFlow MPLS Aggregation
Table 1 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For details on when support for a specific command was introduced, see the command reference documentation.
For information on a feature in this technology that is not documented here, see the "Cisco IOS NetFlow Features Roadmap" module.
Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. 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.
Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.
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