Users Guide

1444 BGP
BGP Example
This example configures iBGP between two routers using the same AS and
each using their own loopback address as update-source.
Router A Configuration
On a router, a loopback interface is created and assigned an IP address. The
router ID is assigned (the same IPv4 address as the loopback interface) and
the IPv4 address of the neighbor (Router B IP address) is assigned. Finally, the
neighbor's update source is assigned to the local loopback interface. This
ensures that the adjacency will remain up, helping to avoid reconvergence
events.
console(config)#ip routing
console(config)#interface lo1
console(config-if-loopback1)#ip address 1.1.1.1 /31
console(config-if-loopback1)#exit
console(config)#router bgp 65001
console(config-router)#bgp router-id 1.1.1.1
console(config-router)#neighbor 1.1.1.3 remote-as 65001
console(config-router)#neighbor 1.1.1.3 update-source loopback 1
Router B Configuration
Router B is the mirror image of the Router A configuration shown above. The
steps are the same except the IP address of the local router and the neighbor
are reversed from the configuration above.
console(config)#ip routing
console(config)#interface lo1
console(config-if-loopback1)#ip address 1.1.1.3 /31
console(config-if-loopback1)#exit
console(config)#router bgp 65001
console(config-router)#bgp router-id 1.1.1.3
console(config-router)#neighbor 1.1.1.1 remote-as 65001
console(config-router)#neighbor 1.1.1.1 update-source loopback 1