BGP Question

Unanswered Question
Mar 22nd, 2008

Hi Guys,

While going through the BGP chapters and docs it is mentioned that if u r a transit AS then run IBGP in full-mesh in u r AS to have better control of the routes.

Can anyone explain me why..?

Thanks in Advance.



I have this problem too.
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Richard Burts Sat, 03/22/2008 - 08:16


There are probably several things that are reasons for this, but probably the most important reason for the requirement for full mesh is that a router running BGP will learn some prefixes from an IBGP neighbor and will not advertise those prefixes to another IBGP neighbor.

Perhaps a simple example may help. Think of an AS with 3 routers running BGP - rtrA. rtrB, and rtrC. So rtrB will learn some prefixes from rtrA. rtrB will not advertise those prefixes to rtrC. To learn those prfixes rtrC will need to peer with rtrA.




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