GARP multicast registration protocol (GMRP)
GARPMulticast Registration Protocol (GMRP) is an IEEE 802.1p method for prioritizing multicast groups within the Generic Attribute Registration Protocol ( GARP).
The GMRP protocol is used to registergroup addresses in local networks. The end device that wants to receive certain multicast data streams registers with a Layer 2 switch for multicast applications by informing the switch of the corresponding attributes via GMRP data packets. In meshed network structures, the end device attributes are communicated to all switches that exchange this information with each other. GMRP includes group membership information and the multicast address of the group. It also indicates whether group members are currently active.
GMRP has the same frame structure as the GARP protocol, it is only identified as a GMPR protocol in the first data field, the protocol ID. The GMRP protocol was replaced by the MMRP protocol, Multiple MAC Registration Protocol (MMRP), in 2007.