Configuring Source IP Address Update

Source IP Address to a Remote Peer displays an example of a Source IP address to remote peer configuration. Router 1 configures the loop-back source address 3.3.3.3 on Router 3 as its neighbor. Router 3 configures the loop-back source address 1.1.1.1 on Router 1 as its neighbor. When the outgoing interface on Router 3 for the initial route fails, because the loop-back source address 3.3.3.3 is still operational, the BGP message for this route is not discarded, but rather uses the new route after BGP reconverges.

Source IP Address to a Remote Peer

Router 1

System(su-config)->router bgp 10
System(su-config-bgp)->bgp router-id 1.1.1.1
System(su-config-bgp)->neighbor 3.3.3.3 remote-as 10
System(su-config-bgp)->neighbor 3.3.3.3 update-source 1.1.1.1

Router 3

System(su-config)->router bgp 10
System(su-config-bgp)->bgp router-id 3.3.3.3
System(su-config-bgp)->neighbor 1.1.1.1 remote-as 10
System(su-config-bgp)->neighbor 1.1.1.1 update-source 3.3.3.3

Configuring Source IP Address to the Peer Update describes how to configure the source IP address to the remote peer.

Configuring Source IP Address to the Peer Update

Step	Task	Command(s)
1	In BGP configuration mode, specify the neighbor this update source IP address will be applied to.	neighbor ip-address remote-as as-num
2	In BGP configuration mode, specify the update source IP address for this neighbor.	neighbor ip-address update-source source-addr