Uniquely identifies a particular instance of a
tunnel between a pair of ingress and egress LSRs.
It is the object identifies multiple instances of
tunnels for the purposes of backup and parallel
tunnels. When the MPLS signaling protocol is
rsvp(2), this value equals to the LSP ID
of the Sender Template object. When the signaling
protocol is crldp(3), there is no equivalent
signaling object. Reference to MPLS-TE-STD-MIB.