Enterasys Networks X-PeditionTM manual Configuring BGP Route Maps

Configuring BGP Route Maps

•Show BGP peer group data: show ip bgp peer-group

•Show routes matching regular AS path expressions: show ip bgp regexp

•Show summary BGP neighbor status: show ip bgp summary

Configuring BGP Route Maps

The following example illustrates the use of a route map to modify inbound data from a neighbor. Any route received from 192.168.10.1 matching the filter values set in AS ACL 110 will be permitted with its weight set to 55 and its local preference set to 60. Note the use of regular expressions.

XSR(config)#router bgp 1

XSR(config-router)#neighbor 192.168.10.1 route-map 55 in

XSR(config-router)#neighbor 192.168.10.1 remote-as 1

XSR(config-router)#route-map 55 permit 5

XSR(config-route-map)#match as-path 110

XSR(config-route-map)#set local-preference 60

XSR(config-route-map)#set weight 55

XSR(config-route-map)#ip as-path access-list 110 permit ^650$

XSR(config-route-map)#ip as-path access-list 110 permit ^700

In the following example, route map 99 marks all paths originating from AS 57 with a MED metric attribute of 99. The second permit clause is needed so that routes not matching AS path list 1 will all be relayed to neighbor 192.168.10.1.

XSR(config)#router bgp 1

XSR(config-router)#neighbor 192.168.10.1 route-map 99 out

XSR(config)#exit

XSR(config)#ip as-path access-list 1 permit ^57_

XSR(config)#ip as-path access-list 2 permit .*

XSR(config)#router bgp 1

XSR(config-router)#route-map 99 permit 5

XSR(config-route-map)#match as-path 1

XSR(config-route-map)#set metric 99

XSR(config-route-map)#route-map 99 permit 10

XSR(config-route-map)#match as-path 2

BGP correctly does not accept any AS path not matching the match clause of the route map. This means that you will not set the metric and the XSR will not accept the route. But, you can configure the router to accept AS paths not matched in the match clause of the route map command by using multiple maps of the same name, some without accompanying set commands.

XSR(config-router)#route-map 44 permit 8

XSR(config-route-map)#match as-path 1

XSR(config-route-map)#set local-preference 3

XSR(config-route-map)#route-map 44 permit 12

XSR(config-route-map)#match as-path 2

In the following example, route map 77 is assigned to outgoing updates for neighbor 192.168.57.4. Route map 77 will prepend AS path 100 to routes that pass ACL 12. The remaining route map configuration allows other routes to be advertised.

XSR(config)#router bgp 33

XSR(config-router)#network 230.57.10.0

XSR(config-router)#network 231.57.10.0

6-22 Configuring the Border Gateway Protocol