[c-nsp] mpls on RR ?

[Oliver Boehmer (oboehmer)]

> Let me rephrase my question>
> if RR not in forwarding path, is there a reason for MPLS on RR

no, not really. 
I've seen one SP doing it so they can run the "same" config/features on
RRs compared to PEs and save on testing, and there is one tiny benefit:
If you run the same MTU on all core links (including the RR links),
PMTUD on the RR will figure out the "right" MSS without relying on
frag-needed from the upstream MPLS node as the RR already pushes a
label, instead of the upstream P node. But that's not a big argument,
IMHO. I would not enable LDP/MPLS on the RR - KISS.. 

Just make extra-sure that RRs will never be in the forwarding path, ISIS
OL-bit or max-metric should be enabled..

	oli