This is the index into the cienaCesmplsTunnelPathTable identifying which explicit-route hop list this dynamic tunnel is constrained to follow when RSVP-TE signals it, rather than letting the protocol pick a path purely by IGP metrics. An admin traces this index to the specific path table entry to see exactly which hops this tunnel is forced through, useful when the tunnel's actual signaled route doesn't match what pure shortest-path routing would have chosen. For example, path index 4 pointing to the path named via-secondary-core-router explains why this tunnel takes a longer route than the IGP-shortest path would otherwise suggest.