Cisco Systems 78-11741-02 manual BGP Peer Group Examples, IBGP Peer Group Example, IPC-345

Configuring BGP

BGP Configuration Examples

The following is a part of the configuration from the BGP speaker 200.200.200.205 from autonomous system 701 in the same example. Neighbor 171.69.232.56 is configured as a normal eBGP speaker from autonomous system 60000. The internal division of the autonomous system into multiple autonomous systems is not known to the peers external to the confederation.

router bgp 701

neighbor 171.69.232.56 remote-as 60000 neighbor 200.200.200.205 remote-as 701

For examples of how the BGP set-communityroute-map configuration command can be used with a confederation configuration, see the last two examples in the section“BGP Community with Route Maps Examples” in this chapter.

BGP Peer Group Examples

This section contains an iBGP peer group example and an eBGP peer group example.

iBGP Peer Group Example

The following example shows how the peer group named internal configures the members of the peer group to be iBGP neighbors. By definition, this is an iBGP peer group because the router bgp global configuration command and the neighbor remote-asrouter configuration command indicate the same autonomous system (in this case, autonomous system 100). All the peer group members use loopback 0 as the update source and use set-med as the outbound route map. The example also shows that, except for the neighbor at address 171.69.232.55, all the neighbors have filter list 2 as the inbound filter list.

router bgp 100

neighbor internal peer-group neighbor internal remote-as 100 neighbor internal update-source loopback 0 neighbor internal route-map set-med out neighbor internal filter-list 1 out neighbor internal filter-list 2 in neighbor 171.69.232.53 peer-group internal neighbor 171.69.232.54 peer-group internal neighbor 171.69.232.55 peer-group internal neighbor 171.69.232.55 filter-list 3 in

eBGP Peer Group Example

The following example shows how the peer group named external-peers is defined without the neighbor remote-asrouter configuration command, making it an eBGP peer group. Each member of the peer group is configured with its respective autonomous system number separately. Thus, the peer group consists of members from autonomous systems 200, 300, and 400. All the peer group members have set-metric route map as an outbound route map and filter list 99 as an outbound filter list. Except for neighbor 171.69.232.110, all have 101 as the inbound filter list.

router bgp 100

neighbor external-peers peer-group

neighbor external-peers route-map set-metric out neighbor external-peers filter-list 99 out neighbor external-peers filter-list 101 in neighbor 171.69.232.90 remote-as 200

neighbor 171.69.232.90 peer-group external-peers neighbor 171.69.232.100 remote-as 300

neighbor 171.69.232.100 peer-group external-peers neighbor 171.69.232.110 remote-as 400

Cisco IOS IP Configuration Guide

IPC-345