EIGRP Support for Route Map Filtering

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 available to allow flexibility in fine-tuning EIGRP network operations.

EIGRP 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 module of the Cisco IOS IP Routing: Protocol-Independent Configuration Guide .

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 command. 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.

The use of route maps to filter traffic is the same for both autonomous-system configurations and named configurations. See the Configuring EIGRP module for more information about autonomous system and named configurations.

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.

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 tag-value

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 filters inbound updates 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. 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 matches external routes from sources that match the 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.
Step 6	set tag tag-value Example: Router(config-route-map)# set tag 5	Sets a tag value on the route in the destination routing protocol when all the match criteria of a route map are met.
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 and enters router configuration mode.
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-router)# distribute-list route-map metric-range in	Filters networks received in updates.

SUMMARY STEPS

1.    enable

2.    configure terminal

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

4.    set metric bandwidth delay reliability loading mtu

5.    match ip route-source {access-list-number| access-list-name} [...access-list-number | ...access-list-name]

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

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

8.    set tag tag-value

9.    exit

10.    router eigrp virtual-instance-name

11.   Do one of the following:

12.    network ip-address [wildcard-mask]

13.    af-interface {default | interface-type interface-number}

14.    next-hop-self eigrp

15.    exit-af-interface

16.    topology {base | topology-name tid number}

17.    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	set metric bandwidth delay reliability loading mtu Example: Router(config-route-map)# set metric 10000 10 255 1 1500	(Optional) Sets the metric value for EIGRP in a route map.
Step 5	match ip route-source {access-list-number| access-list-name} [...access-list-number | ...access-list-name] Example: Router(config-route-map)# match ip route-source 5 80	Redistributes routes that have been advertised by routers and access servers at the address specified by the access lists.
Step 6	match metric {metric-value| external metric-value} [+- deviation-number] Example: Router(config-route-map)# match metric external 500 +- 100	Specifies a match clause that includes 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. 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 7	match source-protocol source-protocol [autonomous-system-number] Example: Router(config-route-map)# match source-protocol bgp 45000	Specifies a match clause that includes 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.
Step 8	set tag tag-value Example: Router(config-route-map)# set tag 5	Sets a tag value on the route in the destination routing protocol when all the match criteria of a route map are met.
Step 9	exit Example: Router(config-route-map)# exit	Exits route-map configuration mode and returns to global configuration mode.
Step 10	router eigrp virtual-instance-name Example: Router(config)# router eigrp virtual-name1	Configures the EIGRP routing process and enters router configuration mode.
Step 11	Do one of the following: address-family ipv4 [multicast] [unicast] [vrf vrf-name] autonomous-system autonomous-system-number address-family ipv6 [unicast] [vrf vrf-name] autonomous-system autonomous-system-number Example: Router(config-router)# address-family ipv4 autonomous-system 45000	Enters address family configuration mode to configure an EIGRP IPv4 or IPv6 routing instance.
Step 12	network ip-address [wildcard-mask] Example: Router(config-router-af)# network 172.16.0.0	Specifies a network for the EIGRP routing process.
Step 13	af-interface {default | interface-type interface-number} Example: Router(config-router-af)# af-interface default	Enters address family interface configuration mode to configure interface-specific EIGRP commands.
Step 14	next-hop-self eigrp Example: Router(config-router-af-interface)# next-hop-self eigrp	Enables EIGRP to advertise routes with the local outbound interface address as the next hop.
Step 15	exit-af-interface Example: Router(config-router-af-interface)# exit-af-interface	Exits address-family interface configuration mode.
Step 16	topology {base | topology-name tid number} Example: Router(config-router-af)# topology base	Configures an EIGRP process to route IP traffic under the specified topology instance and enters address family topology configuration mode.
Step 17	distribute-list route-map map-tag in Example: Router(config-router-af-topology)# distribute-list route-map metric-range in	Filters networks received in updates.