Cisco IOS IP Routing Protocols Configuration Guide, Release 12.2SR - EIGRP Support for Route Map Filtering [Cisco IOS Software Releases 12.2 SR]

Table Of Contents

EIGRP Support for Route Map Filtering

Contents

Information About EIGRP Support for Route Map Filtering

EIGRP Route Map Support

How to Configure EIGRP Support for Route Map Filtering

Configuring EIGRP Metrics Using a Route Map

Verifying EIGRP Metrics

Configuration Examples for EIGRP Support for Route Map Filtering

Configuring EIGRP Metrics Using a Route Map: Examples

Additional References

Related Documents

Technical Assistance

Command Reference

Feature Information for EIGRP Support for Route Map Filtering

EIGRP Support for Route Map Filtering

First Published: May 17, 2004

Last Updated: May 2, 2008

The EIGRP Support for Route Map Filtering feature enables Enhanced Interior Gateway Routing Protocol (EIGRP) to interoperate with other protocols by filtering inbound and outbound traffic based on complex route map options. In addition to the existing route map facility, several extended filtering options are introduced to provide EIGRP-specific match choices.

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Contents

•Information About EIGRP Support for Route Map Filtering

•How to Configure EIGRP Support for Route Map Filtering

•Configuration Examples for EIGRP Support for Route Map Filtering

•Additional References

•Command Reference

•Feature Information for EIGRP Support for Route Map Filtering

Information About EIGRP Support for Route Map Filtering

To implement EIGRP route map filtering, you should understand the following concept:

•EIGRP Route Map Support

EIGRP Route Map Support

EIGRP support for route map filtering enables EIGRP to interoperate with other protocols by filtering inbound and outbound traffic based on route map options. Additional EIGRP-specific match choices are introduced to allow flexibility in fine-tuning EIGRP network operations.

EIGRP now supports the route map filtering capability that exists for other routing protocols to filter routes being redistributed into their protocol. For more details about understanding and configuring route maps, see the Enabling Policy Routing section of the "Configuring IP Routing Protocol-Independent Features" chapter of the Cisco IOS IP Routing Protocols Configuration Guide.

New match options allow EIGRP to filter internal and external routes based on source protocols, to match a metric against a range, and to match on an external protocol metric.

EIGRP can be configured to filter traffic using a route map and the redistribute or distribute-list commands. Using a route map with the redistribute command allows routes that are redistributed from the routing table to be filtered with a route map before being admitted into an EIGRP topology table. Routes that are dynamically received from, or advertised to, EIGRP peers can be filtered by adding a route map option to the distribute-list command.

A route map may be configured with both the redistribute and the distribute-list commands in the same routing process. When a route map is used with a distribute-list command that is configured for inbound or outbound filtering, route packets that are learned from or advertised to EIGRP peers can be processed with the route map to provide better control of route selection during the route exchange process. Redistribution serves as a mechanism to import routes into the EIGRP topology table from a routing table. A route map configured with the redistribute command adds flexibility to the redistribution capability and results in a more specific redistributed route selection.

In summary, demands for EIGRP to interoperate with other protocols and flexibility in fine-tuning network operation necessitate the capability to filter traffic using a route map.

How to Configure EIGRP Support for Route Map Filtering

This section contains the following tasks:

•Configuring EIGRP Metrics Using a Route Map (required)

•Verifying EIGRP Metrics (optional)

Configuring EIGRP Metrics Using a Route Map

Perform this task configure EIGRP metrics using a route map. In the Detailed Steps below, the EIGRP metrics used for filtering are configured within a route map. The first match clause defines EIGRP routes that contain an external protocol metric between 400 and 600 inclusive; the second match clause defines EIGRP external routes that match a source protocol of BGP and the autonomous system 45000. When the two match clauses are true, a tag value of the destination routing protocol is set to 5. This route map can be used with the distribute-list command, see the "Configuring EIGRP Metrics Using a Route Map: Examples" section for an example configuration.

SUMMARY STEPS

1. enable

2. configure terminal

3. route-map map-tag [permit | deny] [sequence-number]

4. match metric {metric-value | external metric-value} [+- deviation-number]

5. match source-protocol source-protocol [autonomous-system-number]

6. set tag source-protocol [autonomous-system-number]

7. exit

8. router eigrp as-number

9. network ip-address

10. distribute-list route-map map-tag in

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 metric_range

Enters route-map configuration mode.

Step 4

match metric {metric-value | external metric-value} [+- deviation-number]
Example:

Router(config-route-map)# match metric external 500 +- 100

Specifies a match clause that redistributes EIGRP routes that match an internal or external protocol metric.

•metric-value—Internal protocol metric, which can be an EIGRP five-part metric. The range is from 1 to 4294967295.

•external—External protocol metric. The range is from 1 to 4294967295.

•+- deviation-number—(Optional) Represents a standard deviation. The deviation can be any number. There is no default.

•In this example, EIGRP routes that contain an external protocol metric between 400 and 600 inclusive are redistributed.

Note When you specify a metric deviation with the + and - keywords, the router will match any metric that falls inclusively in that range.

Note The external protocol metric is not the same as the EIGRP assigned route metric which is a figure computed from EIGRP vectorized metric components (delay, bandwidth, reliability, load, and MTU).

Step 5

match source-protocol source-protocol [autonomous-system-number]
Example:

Router(config-route-map)# match source-protocol bgp 45000

Specifies a match clause that redistributes EIGRP external routes that match a source protocol.

•source-protocol—Protocol to match. The valid keywords are bgp, connected, eigrp, isis, ospf, rip, and static. There is no default.

•autonomous-system-number—(Optional) Autonomous system number. The autonomous-system-number argument is not applicable to the connected, static, and rip keywords. The range is from 1 to 65535. There is no default.

•In this example, EIGRP external routes that match a source protocol of BGP and the autonomous system 45000.

Step 6

set tag tag-value
Example:

Router(config-route-map)# set tag 5

Sets a tag value of the destination routing protocol when all the match criteria of a route map are met.

•In this example, the tag value of the destination routing protocol is set to 5.

Step 7

exit
Example:

Router(config-route-map)# exit

Exits route map configuration mode and returns to global configuration mode.

Step 8

router eigrp as-number
Example:

Router(config)# router eigrp 1

Configures the EIGRP routing process.

Step 9

network ip-address
Example:

Router(config-router)# network 172.16.0.0

Specifies a network for the EIGRP routing process.

Step 10

distribute-list route-map map-tag in
Example:

Router(config)# distribute-list route-map metric_range in

Filters networks received in updates.

•This example uses a route map to filter the networks. The route map named "metric_range" was identified in Step 3 above.

Verifying EIGRP Metrics

To verify that both the EIGRP metric and the external protocol metrics have been configured, perform the following step.

SUMMARY STEPS

1. enable

2. show ip eigrp topology [autonomous-system-number | ip-address [mask]] [active | all-links | detail-links | pending | summary | zero-successors]

DETAILED STEPS

Step 1 enable

Enables privileged EXEC mode. Enter your password if prompted.
Router# enable
Step 2 show ip eigrp topology [autonomous-system-number | ip-address [mask]] [active | all-links | detail-links | pending | summary | zero-successors]

Use this command to display the internal EIGRP metrics for a specified IP address, for example:
Router# show ip eigrp topology 172.16.1.0/24
IP-EIGRP (AS 45000): Topology entry for 172.16.1.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 2169856
  Routing Descriptor Blocks:
  0.0.0.0 (Serial4/0), from Connected, Send flag is 0x0
      Composite metric is (2169856/0), Route is Internal
      Vector metric:
        Minimum bandwidth is 1544 Kbit
        Total delay is 20000 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 0
In the following example, the external EIGRP metrics for a specified IP address are displayed:
Router# show ip eigrp topology 192.168.1.0/24
IP-EIGRP (AS 45000): Topology entry for 192.168.1.0/24
  State is Passive, Query origin flag is 1, 1 Successor(s), FD is 2169856
  Routing Descriptor Blocks:
  0.0.0.0 (Serial4/0), from Connected, Send flag is 0x0
      Composite metric is (2169856/0), Route is External
      Vector metric:
        Minimum bandwidth is 1544 Kbit
        Total delay is 20000 microseconds
        Reliability is 255/255
        Load is 1/255
        Minimum MTU is 1500
        Hop count is 1
        External data:
        Originating router is 10.89.245.1 
        AS number of route is 0
        External protocol is Connected, external metric is 0
        Administrator tag is 0 (0x00000000)
Configuration Examples for EIGRP Support for Route Map Filtering

This section contains the following configuration example:

•Configuring EIGRP Metrics Using a Route Map: Examples

Configuring EIGRP Metrics Using a Route Map: Examples

The following example shows how to configure a route map to match an EIGRP external protocol metric route with an allowable deviation of 100, a source protocol of BGP, and an autonomous system 45000. When the two match clauses are true, the tag value of the destination routing protocol is set to 5. The route map is used to distribute incoming packets for an EIGRP process.
route-map metric_range
 match metric external 500 +- 100
 match source-protocol bgp 45000
 set tag 5
!
router eigrp 1
 network 172.16.0.0
 distribute-list route-map metric_range in
The following example shows how to configure a route map to match EIGRP routes with a metric of 110, 200, or an inclusive range of 700 to 800. When the match clause is true, the tag value of the destination routing protocol is set to 10. The route map is used to redistribute EIGRP packets.
route-map metric_eigrp
 match metric 110 200 750 +- 50
 set tag 10
!
router eigrp 1
 network 172.21.1.0/24
 redistribute eigrp route-map metric_eigrp
Additional References

The following sections provide references related to the EIGRP Support for Route Map Filtering feature.

Related Documents

Related Topic

Document Title

EIGRP overview and configuration

"Configuring EIGRP" module

IP routing commands including syntax, usage guidelines, and examples

Cisco IOS IP Routing Protocols Command Reference

Technical Assistance

Description

Link

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http://www.cisco.com/techsupport

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS IP Routing Protocols Command Reference at http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

•match metric (IP)

•match source-protocol

•show ip eigrp topology

Feature Information for EIGRP Support for Route Map Filtering

Table 1 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

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.

Table 1 Feature Information for EIGRP Support for Route Map Filtering

Feature Name

Releases

Feature Information

EIGRP Support for Route Map Filtering

12.2(33)SRA
12.2(33)SXH
12.3(8)T

The EIGRP Support for Route Map Filtering feature enables EIGRP to interoperate with other protocols by filtering inbound and outbound traffic based on complex route map options. In addition to the existing route map facility, several extended filtering options are introduced to provide EIGRP-specific match choices.

The following commands were introduced or modified by this feature: match metric (IP), match source-protocol, show ip eigrp topology.

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