[c-nsp] Cisco ME3600X MPLS OSPF balanced LSP, non LSP drop packets

[Mark Tinka]

On 15/Sep/15 15:28, Brett . wrote:

> My network has a limited MPLS deployment currently. It is not enabled
> everywhere. The example I provided is a lab.

This could get interesting. Suggest you give this more thought, before
you start potentially blackholing traffic around your network.

>
> This not expected behavior and Cisco has confirmed for me that it is not.

Really - I find this interesting...

>
> Other Cisco platforms do not drop the traffic such as the ASR920.

So you have the very same topology and setup working fine on an ASR920?

>
> The ME3600X should not be dropping the packets, it should be dropping
> the mpls tag and then forwarding the packets as a normal routed packet
> according to the FIB.

Yes, but in you case, you have an ECMP destination, where one path is
MPLS-capable and the other isn't. I've never ran such a topology, but
something tells me "weird and strange" things will happen when you have
ECMP paths with different forwarding paradigms.

>
> MPLS services would fail on that path. But routing should not fail.

MPLS does fail - your packets are dropped because Vl2003 does not
support MPLS. The routing is working fine, however.

I think if you disable MPLS on Vl2003, or enable MPLS on Vl2004, things
should work. The asymmetric setup might present issues.

That said, I'd be keen to hear from you how this setup is working on an
ASR920.

Mark.