The value of vRtrPimNgIfNeighborGenId 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 vRtrPimNgIfNeighborGenId
is received from a neighbor, any old Hello information about that
neighbor is discarded and superseded by the information from the new
Hello message.