0

Routers announce to their iBGP peers, the Best routes for each networks it has in its database

Is it possible, to announce additionally to the Best route, also all the Valid routes to the iBGP peers ?

1
  • 1
    An iBGP router cannot announce iBGP-learned prefixes to iBGP peers. That is why iBGP requires a full mesh or a mitigation (route reflectors or confederations). – Ron Maupin Jun 7 at 19:16
2

This is possible. There is a feature called additional-paths advertise|install which is an enhancement to the BGP protocol, but it must be supported by both parties. Also check the BGP PIC feature.

Check This paper for further reference

1
  • The router can advertise up to 3 additional paths, not all valid routes – Ron Trunk Jun 7 at 19:31
2

A Cisco router can install multiple paths into the RIB using the maximum-paths command. This will allow the router to 'load share' among the paths.

However, the router will only advertise the best path to its peers, regardless of how many paths are in the RIB.

2
  • Not entirely accurate statement. Maximum-paths is the amount of paths that can be taken into RIB/FIB for a given prefix, but this is different. Many vendors have support for additional-paths nowadays, which can achieve what is asked in the question. – Danail Petrov Jun 7 at 19:28
  • 1
    Yes, I was just reviewing that as you wrote this. Thanks for the tip. – Ron Trunk Jun 7 at 19:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.