[c-nsp] lsp ping between JNPR and Cisco

Marlon Duksa mduksa at gmail.com
Fri Dec 5 17:57:06 EST 2008

Our RSVP tunnel endpoints are JNPR boxes (M320) and a transit node is Cisco
(7600). When we try to initiate MPLS ping from JNPR to JNPR through Cisco,
the mpls ping fails.
The reason is that JNPR is always setting IP TTL as 1. Since the Cisco is a
penultimate node, it strips the label, decrement the IP TTL (to 0) and send
the packet to JNPR. JNPR discards it since the IP TTL is 0.

Does anyone know if there is any workaround to this?

It looks to me that the only option is to try to set the IP TTL in MPLS ping
from ingress JNPR to something > 0. Unfortunately there is no provision that
would allow us to do this.
On the other hand, Cisco won't honor 'no-ttl-decrement' statement on the
penultimate if MPLS TTL is greater then the IP TTL (which currently is since
JNPR MPLS TTL is set to 255).


More information about the cisco-nsp mailing list