[c-nsp] URPF MAC check

[Dobbins, Roland]

On Nov 23, 2012, at 10:26 PM, Gert Doering wrote:

> BGP routing is *not* symmetric.  Please repeat this 100 times.

They understand that.  What's actually being discussed is some combination of layer-2 and layer-3 policy enforcement.  The uRPF thing is a red herring; static policies (probably matching the prefix-list filtering applied to a given peering session) would work, there's no need for dynamism.

The DDoS thing is a red herring, too - existing telemetry mechanisms allow traceback.  The main potential benefit something like this would be to prevent traffic dumping in a shared-interconnect-medium IX environment, along with some corner-cases like the one Saku described.

-----------------------------------------------------------------------
Roland Dobbins <rdobbins at arbor.net> // <http://www.arbornetworks.com>

	  Luck is the residue of opportunity and design.

		       -- John Milton