Bgp Suppress-inactive

[Jonn cos]

Hi all experts.

I was viewing the purpose of this command came around this link

http://blog.zakir.net/index.php?/archives/20-BGP-suppress-inactive.html

"That's what the “bgp suppress-inactive” command do. It  supresses the advertisement of BGP inactive/rib-failure route. Now here  is a gotcha. BGP doesn't always supress inactive/rib-failure routes. It  supresses the rib-failure routes only if the next-hop of BGP rib-failure  route is different from the next-hop of same route currently installed  in the routing table."

I just wanted to know that, i didnt see the above point in any cisco doc. When i tested it in lab, the point was 100% correct. Can someone help me to find where this point is listed in cisco docs ? or any more insight about this particular behaviour.

thanks

[hbruyere · Accepted solution]

Hello!

The intention of the suppress-inactive command is indeed to advertise rib-failure routes only when IGP and BGP nexthop are matching.

And it is also true that the command reference is not very explicit about this.

If you are looking for a more 'official' statement regarding this command, you can refer to the release notes of the following bug, which was actually fixing

a problem where rib-failure routes with BGP and IGP nexthop mismatch were still advertised:

CSCdx26714

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCdx26714

Symptom :

  If the prefix get Rib-Failre when installing into bgp table because of 
  there is already has a prefix in the routing table with a prefered admin 
  distance (like already learnd by ospf), then this prefix should not be 
  advertised to other bgp peers unless the next-hop is the same as the prefix
  in the ip routing table.
  But the behavior is that even if the next-hop is the same, this prefix still
  does not advertise to it's bgp peers.

Regards,

Herve

[Jonn cos]

Really really thanks alot !!!!