15 M ULTICASTING AND IGMPCOMMANDSOverview This section describes the Multicasting and related IGMP (Internet GroupManagement Protocol) commands accessible from the CLI. Multicast is acommunication pattern in which a host sends packets to a group of destinationhosts that have expressed interest in being members of certain groups. The majoradvantage of Multicast is that it is an efficient method for moving messages, andcan decrease the network load.IGMP is the communications protocol used by hosts to inform theirimmediately-neighboring routers that they are interested in receiving multicastmessages. By using IGMP, each node can become a member of one or moremulticast groups and receive the multicast packets sent to those groups. The IGMPis also used by the routers to periodically check whether the known groupmembers are still active.The following table identifies the Multicast and IGMP commands described in thischapter:Multicast CommandsSet Commandsset ip multicast heartbeat The set ip multicast heartbeat command configures multicast monitoring for aspecified multicast group or interface. The command has the followingparameters:interface group time Category CommandTypeCommand NameMulticast Set set ip multicast heartbeatset ip multicast proxy interface IGMP Set set ip igmp [eth:1|slot:x/port:y]Join join ip igmp Leave leave ip igmp List list ip igmpShow show ip igmp [eth:1|slot:x/port:y]
