Hi Nick,
Each stub network simply points a default route to you. Or you do a
"default-originate" on the eBGP peering to both stub networks. They don't
need to see the other /19 in their routing table - a default route is
sufficient. Simple solution... :-)
Check out
www.cisco.com/public/cons/seminars/NANOG23/BGP-Multihoming-Techniques.pdf
for a configuration example which solves this problem.
philip
--At 22:17 17/06/2002 +0800, Nick Kraal wrote: >We have a customer that has transit services from us. They have split their >network into two /19 and run BGP with us at two different locations. Each >/19 is actually for two seperate businesses; one a tier-2 ISP and the other >VoIP provider. Two physically sperate networks are also running the same ASN >and are to peer with each other via our network. There is no internal >interconnectivity between them or any IGP running. > >The problem lies in that to reach each other they need to 'transit' via our >network and according to BGP, one cannot announce back the client prefixes >learnt from the other network and vice versa as both of them are running the >same ASN. This is to prevent routing loops. > >In this case is there a method to overwrite this so that the first /19 >network will be able to reach the second /19 network via ours? > >Thanks in advance. > >-nick/
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:13:47 EDT