Route My World!

A CCNA/CCNP/CCIE Blog

BGP RIB Failure

Posted by Aragoen Celtdra on August 1st, 2011

While going through some BGP examples in Routing TCP/IP Volume II, I came across an issue where RIB failures continue to pop up in the show commands. To illustrate see the following topology I recreated from the book (pg 175, fig 3-6 on Routing TCP/IP II book)

sh ip bgp produces the following output with the “r>” indicating that there is a RIB failure in router Vail.

sh ip bgp rib-failure provides a clue as to what caused the RIB failure

Further troubleshooting shows why

Telluride is advertising prefixes 192.168.1.200/30, 192.168.50.0, and 192.168.75.0 via IBGP towards Vail. Vail, however, is also learning these same routes via OSPF through Aspen. As shown in the sh ip route output for one of the routes above, an OSPF advertisement has an AD of 110, whereas an IBGP advertisement has an AD of 200. Even though the routes are in Vail’s BGP table, the OSPF route is installed in the routing table because of lower administrative distance. BGP then throws a fit because he has the routes in his table and the router ignored him. ;-)

This is normal operation for BGP. In fact, even though Vail does not use the route via BGP it is not suppressed or thrown out. If you check the ip routing table in Taos, you’ll see that BGP is sending these same routes from Vail. So at least BGP is happy there

6 Responses to “BGP RIB Failure”

  1. Mirek BurnejkoNo Gravatar Says:

    Man I don’t see any updates from you. Where are you? :)

  2. Aragoen CeltdraNo Gravatar Says:

    Hehe. I’m around. ;-) I’ve just been very busy with work and 3 kids. I’ve been thinking about updating but just haven’t had the chance. 

  3. NajamNo Gravatar Says:

    Very interesting article and the website is focused and very well maintained. Thanks for the information and keep posting.

  4. J ThomasNo Gravatar Says:

    Hi Aragoen,
    Just came to this site from google now.  I am Preparing for CCNP now. Currently preparing BGP section.
    Thanks a lot for the tutorials.
    J Thomas.
     
     
     

  5. Adohen 77No Gravatar Says:

    Love the site.   Was just working a data center move with some as-path and prepends.  turned into a mess with some GIS connections.  redistribution in eigrp. 
     
     
     

  6. Lalit SharmaNo Gravatar Says:

    How to solve this issue…. i am getting this output and unable to ping the RIB failure networks.

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