iBGP Multi-Link Question

Answered Question

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


Correct Answer by Giuseppe Larosa about 8 years 8 months ago

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


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Giuseppe Larosa Mon, 09/08/2008 - 12:51
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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


Correct Answer
Giuseppe Larosa Mon, 09/08/2008 - 22:18
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  • Super Silver, 17500 points or more
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    Founding Member

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


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