I don't think you've given all the details so it's hard to say, but do you have graceful-restart configured in bgp / NSF?
-Blake On Wed, Aug 7, 2013 at 1:27 PM, Drew Weaver <[email protected]> wrote: > Greetings, > > I am configuring BGP on an IOS XR 4.2.1 system and I have noticed that > even though the router immediately determines that a next hop is > unreachable it keeps the routes installed until BGP times out. > > Under normal circumstances 'show bgp nexthop ip.add.re.ss' looks like this: > > RIB Related Information > Gateway: reachable, non-Connected route, prefix length 32 > > When there is a connectivity failure between the two systems it almost > immediately changes to this: > > RIB Related Information > Gateway: unreachable, non-Connected route, prefix length 4 > > Why then, given that it knows it's no longer a valid nexthop would it > continue to route prefixes to it? > > Routing entry for 192.168.116.0/24 > Known via "bgp xxxxx", distance 200, metric 0, type internal > Installed Aug 7 22:08:15.809 for 00:12:09 > > It also continues to announce this route to upstream peers; again even > though it knows it can't reach the next hop. > > It does eventually stop doing this; but only after the normal BGP timeout > period (which I believe is 300 seconds). > > Is there a setting you need to enable so that if there is a RIB failure it > will immediately stop doing this? > > Thanks, > -Drew > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
