From: Mark Salmon (masalmon@xxxxxxxxx)
Date: Fri Mar 02 2001 - 13:28:18 GMT-3
No, that will not work as if one of the links go down, (say on r1), then r2 wil
l
not send to r1 via IBGP the routes it learned from its EBGP peer.
"David T. Absalom" wrote:
> I believe you could use a outgoing route map for the ebgp sessions on r1 and
> r2 to only allow local routes be advertised, i.e.
>
> ip as-patch access-list 1 permit ^$
>
> route-map notransit permit 10
> match as-path 1
>
> This would only allow routes from AS1100 to be advertised via ebgp.
>
> Hope this helps...
>
> dave
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Mark Salmon
> Sent: Friday, March 02, 2001 9:42 AM
> To: ccielab@groupstudy.com
> Subject: BGP problem
>
> I have a BGP issue I want to bring to the group.
>
> as500 --------ebgp------as600
> | |
> | |
> ebgp ebgp
> | |
> | |
> r1:as1100--------ibgp-----r2:as1100
>
> I need r1 to use as500 exclusively as its exit and entrance as well as
> r2 must use as600 exclusively as its entrance and exit. However, if the
> links between r1 and as500 is lost, it must reroute through r2 to
> as600. The same applies to r2. No load balancing is necessary. That
> is not the problem, I am OK with setting up local preferences etc.
>
> The problem is, I do not want as1100 to be a transit as for Internet
> routes.
>
> My idea is to use community lists and no export option from r1 to as500
> as well as r2 to as600. I used ip as-path access lists and that is
> where the problem starts. I do not see the as1100 routes on as500 or
> as600 routers
>
> Here is my config on one router (it is virtually identical on the other
> router):
>
> . router bgp 1100
> network 192.168.1.0
> network 192.168.3.0
> neighbor 192.168.2.2 remote-as 1100
> neighbor 192.168.25.2 remote-as 500
> neighbor 192.168.25.2 send-community
> neighbor 192.168.25.2 route-map nointernet out
> !
> ip classless
> ip as-path access-list 1 permit _1100_
>
> route-map nointernet permit 10
> match as-path 1
> set community no-export
>
> --
>
> Mark Salmon
> Network Support Engineer - SBC OP HQ
> Cisco Systems Inc
> 8735 W. Higgins Road Suite 300
> Chicago IL 60631
> Phone:773-695-8235
> Pager:800-365-4578
> email: masalmon@cisco.com
> Empowering The Internet Generation.
>
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