MPLS VPN load sharing when multihoming

Unanswered Question
Feb 27th, 2007

Any one know of best practices for outbound load balancing when multihoming to 2 different service providers in an mpls vpn.

I have referred to this document (http://www.cisco.com/warp/public/459/40.html) which states the only way to do this is by assigning metrics/weights to a certain range of prefixes learned from one provider, hence load sharing.

Turning up bgp multipath on the CE would be optimal but since AS PATHs are different the best path selection will be different. Could we possibly turn of best path selection for AS paths (bgp bestpath as-path ignore) and make multipath work? Would that install 2 routes for the same prefix in the RIB?

Thanks

Ariful Huq

I have this problem too.
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smalkeric Mon, 03/05/2007 - 13:34

Yes you can turn off best path selection for AS path and have multipath work. For a route to be populated in routing table BGP has various metrics for its selection. AS path is one of the metrics it uses for best route selection, so I dont think there should be any problem with it.

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