04-17-2008 11:42 AM - edited 03-03-2019 09:36 PM
Hi,
Hopefully a simple eBGP question:
If I have 2 edge routers in an AS, and 2 edge routers in another AS is it best practices to have them in a square, or triangles?
By this I mean AS1 has router 1 and router 2 (running iBGP between them), and AS 2 has the same.
Is it best practice to have an eBGP peer between AS1 router 1 <-> AS2 router 1, and AS1 router 2 <-> AS2 router 2, or:
AS1 router 1 peering with AS2 router 1 and 2, and AS1 router 2 peering with AS2 router 1 and 2.
Either way, can somebody confirm the best practice and why?
Any help would be greatly appreciated.
04-18-2008 10:50 AM
Andy
if layer ONE allows for redundancy, meaning R1-AS1 has 2 different links to R1&R2-AS2 then I would fully mesh.
if not, there are still some benefits.
I would set up 3 session on each router.
in this case traffic outboud, would always exit via external AS. so R1-AS1 >> R1 or R2 -AS2 (Unless u have manipulated IBGP attributes).
why would I fully mesh ?
1-Redundancy.
2-less hops, by meshing. u are allowing BGP to use less hops which sometimes customers like to see (unless MPLS is used)
HTH
Sam
04-18-2008 01:38 PM
Sam,
Many thanks. I deployed with multiple eEBP peers i.e. each router has 2 x eBGP and 1 x iBGP for redundancy and found faster convergence.
Many thanks for your reply, it's good to get validation :-)
All the very best,
Andy
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