[c-nsp] why are packets not following the more specific route - xr 4.1.2 (asr9k)

Saku Ytti saku at ytti.fi
Thu Aug 15 16:14:53 EDT 2013


On (2013-08-15 14:35 -0500), Aaron wrote:

> The next hop of those bh routes is an ip address on the distant end of a
> layer 2 segment which is connected to that border asr9k

Your popped label has L2 rewrite information, so no IP lookup is required.

In VRF you can force single label for whole VRF, which will mean that
you'll always do IP lookup. These are called 'aggregate label'.

In some platforms you can cause IP lookup to occur if you put egress ACL in
the egress interface, just make sure it does _something_ so it's not
optimized away.

Causing IP lookup in egress PE may have undesirable side-effects, such as
they break hub+spoke VRF topologies.
-- 
  ++ytti


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