[c-nsp] Implementing Unicast RPF multi-homed network

Seth Mattinen sethm at rollernet.us
Sat Jan 24 16:59:07 EST 2009


root net wrote:
> Hello,
> 
> I was wondering where the best place would be to implement Unicast RPF on a
> multi-homed network with full routes / filtered routes and private peering
> interconnects with local ISPs (small businesses)?  Currently we just use
> ACLs to do drop spoofing on our upstream interfaces.  I have been doing some
> reading and it says to implement at the edge not core unless you manually
> setup the routes. I would like to place this on the outside interface of
> each router connected to our upstreams and on the interface that is
> connected to each local ISP.  The problem is we are doing asymmetric routing
> at the edge/core b/c our links are not the same size.  So how can we
> accomplish this?  I think way to overcome would be to use BGP attributes
> using weight maybe?
> 
> Any thoughts and any other suggestions.  Would like to see what others are
> doing for this.

Use loose mode instead of strict.

~Seth


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