BGP errors

[M.Sultan]

Hello guys

I run BGP, some routers has routes and some others shows this log message, Please detail common errors occurs in BGP in reply.

*May 11 19:59:57.942: %BGP_SESSION-5-ADJCHANGE: neighbor 172.31.96.2 IPv4 Unicast topology
base removed from session Peer closed the session

Thank 

[Harold Ritter]

Hi @M.Sultan ,

What address family has been configured for BGP?

If ipv4 unicast, you can use "show bgp ipv4 unicast summary" to get the status of all the sessions and "show bgp ipv4 unicast neighbor x.x.x.x" to get the detailed status of a session in particular.

Regards, 

[David Ruess]

The message states the "Peer closed the session". So the peer didn't get something it needed from that router to keep the BGP session open. Lots of reasons can cause this. You need to log into the other router and check logs and configuration to see what the issue is.

-David

[paul driver]

Hello
The bgp peers lost their reachability to each other. possibly due to a physical issue (dropping/flapping) of an interface or losing ip reachability to each other peering address. ( route-recalculation. lost of route)