The value of tmnxPimSnpgIfNbrGenId indicates a randomly generated
32-bit value that is regenerated each time PIM forwarding is
started or restarted on the interface, including when the router
itself restarts. When a Hello message with a new
tmnxPimSnpgIfNbrGenId is received from a neighbor, any old Hello
information about that neighbor is discarded and superseded by the
information from the new Hello message.