[c-nsp] MPLS over GRE

Gregoire Huet gregoire.huet at ip-max.net
Tue Nov 25 16:27:44 EST 2014


Hello,

A tunnel, on a DMVPN hub on a 7600/3BXL [1], doesn't get MPLS tagged 
packets flowing in.

MPLS traceroute shows a DownStream Map mismatch at the tunnel entrance hop,
followed by looping packets until TTL 30 on the same IP.

   0 10.0.52.22 MRU 9050 [Labels: 712848 Exp: 0]
L 1 10.0.55.32 MRU 9064 [Labels: 28 Exp: 7] 24 ms
L 2 10.0.52.30 MRU 1480 [Labels: implicit-null Exp: 0] 200 ms
D 3 10.0.54.3 4 ms
f 4 10.0.54.3 0 ms
f 5 10.0.54.3 4 ms
f 6 10.0.54.3 0 ms
....

There is one way to have packets accepted inside the tunnel the 'in' 
way: it's to perform
'no mls mpls tunnel-recir' and then 'mls mpls tunnel-recir'. At that 
point, the packets flow
for about 2 seconds, and stop.

MPLS packets have no problem to get out of the tunnel (they enter it on 
the remote,
which is a 7206).

So, i really suspect a CEF entry problem, although that the entries look 
"good".
It seems that i don't have many ways to interact with the entries.

Any way to help me solve the issue is of course very welcome.

Thank you
Best regards,

Gregoire

[1] 7604 / WS-SUP720-3BXL - WS-X6704-10GE/WS-X6748-GE-TX/WS-X6516A-GBIC 
/ 15.1(3)S1





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