[c-nsp] Label still appearing in traceroute after disabling ttl propagation

[John Neiberger]

W
e're running into an interesting problem. We have a simple lab setup like
this:

CE1 -- PE1 --- P1 --- P2 --- PE2 --- CE2

We have "mpls ip-ttl-propagate disable" on all PE and P routers, but if we
trace from CE1 to CE2, we still see an MPLS label coming from the PE2
router. If we trace CE2 to CE1, we see a label on the hop from P1 to PE1.

If we have ttl propagation completely disabled, why would we still see the
label and P-to-PE link in the path?

All P and PE routers are IOS XR running 4.1.0.

Thanks,
John