Huawei The Hello message for the Resource Reservation Protocol (RSVP) has been defined to establish and maintain basic signaling node adjacencies for Label Switching Routers (LSRs) participating in a Multiprotocol Label Switching (MPLS) traffic engineered (TE) network. The Hello message has been extended for use in Generalized MPLS (GMPLS) network for state recovery of control channel or nodal faults.