OSPF to BGP redistribution issue

[dariopalermo]

Hi guys,

I'm trying to fix this situation:

Router P (provider) has to link, one to Router A (10G) and the other to Router B (1G). On both links there is an OSPF router 50 set up to publish routers from the providers to the internal routers. Router A and B exchange routes via BGP.

I want to have the router A path (10G) in the routing table of both routers.

To make this happen I tried to  put distance, on router B, 255 in the router ospf 50 config to make the router prefer the bgp received route from router A over the ospf route received by router P.

This works until router A stop publishing the routes... at that moment router B puts into it's routing tables the ospf received routes and that is just fine... but when router A lino to router P goes back online router B sticks with the ospf routes.

Any suggestion? Thanks.

Bye, Dario

[rishrapsody1]

Can you please share ospf and bgp config of both router A and router B.

Also, please share 'show ip route <prefix>' and 'show ip bgp <prefix>' on router B for destination network.

[rishrapsody1]

seems like you have ospf to bgp redistribution enabled on router B as well.
IGP when redistributed to BGP sets weight has 36768 and thus will not let other path to get preferred.
Option is to set higher wieght for router A on router B. i.e neighbor <router A ip> weight 40000

[Jon Marshall]

Are you redistributing OSPF into BGP ? 

If so check the weight values in the BGP routing table on router B when it has taken over. 

Jon

[dariopalermo]

Sorry for the delay guys, and thanks for replying.

The issue was related to the "order of events": when switch B did the redistribuition into BGP of the incriminated route before receiving it from router A, it discarded the latter.

The solution was to make router A and B neighbors in the OSPF 50 area (I connected the 2 over a new p2p link).

Bye,

Dario