iBGP Multi-Link Question

[jcartier]

I'm in a scenario where I have two routers, configured with two loopbacks, connected together via two links. I'm in the process of transitioning from one loopback to the other and I was wondering if there are any caveats to having two sessions up...one BGP session to the first lookback (existing), then another BGP session up to the second loopback (new).

I don't believe their should be any issues with this...and I don't see any documentation suggesting otherwise...just thought I'd ask to be certain :-)

ROUTER1============ROUTER2

Lo1:10.1.1.1/32 Lo1:10.1.2.1/32

Lo2:10.1.1.2/32 Lo2:10.1.2.2/32

[Giuseppe Larosa]

Hello Jeff,

your understanding is correct: you can setup the second iBGP session that uses the loop2 on both routers.

Some issues can arise if redistributing ospf into/from BGP: it has been noticed that is necessary to have OSPF router-id = BGP router-id

If there isn't any redistribution of BGP or into BGP it should be a smooth transition.

Hope to help

Giuseppe

[jcartier]

The OSPF router-ids were changed prior to this upcoming change...thus the router-ids will be the source loopbacks for BGP. No problems then? :)

THanks!

[Giuseppe Larosa · Accepted solution]

Hello Jeff,

I think you shouldn't have any problem in this migration to loop2 iBGP endpoints.

It should be better if iBGP next-hop = OSPF router-id it is more safe it will pass the sync test (if sync is not disabled).

Hope to help

Giuseppe