42 GMRP C ONFIGURATIONGMRP Overview GMRP (GARP Multicast Registration Protocol), based on GARP, is used formaintaining multicast registration information of the switch. All GMRP-capableswitches can receive multicast registration information from other switches,dynamically update local multicast registration information, and send their ownlocal multicast registration information to other switches. This informationswitching mechanism keeps consistency of the multicast information maintainedby every GMRP-supporting device in the same switching network.A host sends a GMRP Join message, if it is interested in joining a multicast group.After receiving the message, the switch adds the port on which the message wasreceived to the multicast group, and broadcasts the message throughout theVLAN where the receiving port resides. In this way, the multicast source in theVLAN gets aware of the existence of the multicast group member. When themulticast source sends multicast packets to a group, the switch only forwards thepackets to ports connected to the members of that group, thereby implementingLayer 2 multicast in the VLAN.Configuring GMRP The main tasks in GMRP configuration include:■ Enable GMRP globally■ Enable GMRP on a portGMRP must be enabled globally before it is enabled on a port.Enabling GMRP GloballyEnabling GMRP on thePortPerform the following configuration in Ethernet port view.Table 330 Enable GMRP globallyOperation Command DescriptionEnter system view system-view -Enable GMRP globally. gmrp RequiredDisabled by default.Table 331 Enable/Disable GMRP on the portOperation Command DescriptionEnter system view system-view -Enter Ethernet port view interface interface-typeinterface-number-Enable GMRP on the port gmrp RequiredDisabled by default.
