[c-nsp] BGP Upstream in different interfaces.

[Michael Smith]

Hello:


> From: Alexandra Alvarado <aaaa at telconet.net>
> Date: Mon, 14 Feb 2005 02:11:41 -0500
> To: <cisco-nsp at puck.nether.net>, 'Alexandra Alvarado' <aaaa at telconet.net>
> Subject: [c-nsp] BGP Upstream in different interfaces.
> 
> Hello,
> 
>  
> 
> I have three ISP Provider for backup, and via BGP I have been configured
> three network group each one preferred for each provider and as backup for
> the others (adding as-path prepend), it works well for download  but for
> upstream all the traffic only goes for one preferred interface (local
> preference 120).
> 
>  
> 
> I would like to know if is possible to choose the upstream traffic by
> selected networks without applying "service policy" in the interface but by
> BGP in the neighbors?
> 
>  
> 

Sure.  Let's say you wanted to prefer AS701 out to Peer A and AS1239 out to
Peer B, everything else is equally balanced.

ip as-path access-list 2 permit .*
ip as-path access-list 5 permit _701_
ip as-path access-list 6 permit _1239_

route-map PEER-A-IN permit 5
match as-path 5
set local-preference 120

route-map PEER-A-IN permit 10
match as-path 2
set local-preference 100

route-map PEER-B-IN permit 5
match as-path 6
set local-preference 120

route-map PEER-B-IN permit 10
match as-path 2
set local-preference 100

router bgp xxx
neighbor peer.a.ip route-map PEER-A-IN in
neighbor peer.b.ip route-map PEER-B-IN in

The regexp in the access list above could certainly be refined.  You could
also add other AS to the existing as-path access-list above, or add a new
access-list and make it a different local-preference within the route-map.

Mike
-- 
Michael K. Smith               NoaNet
206.219.7116 (work)         866.662.6380 (NOC)
mksmith at noanet.net      http://www.noanet.net