A protocol used to support IP Multicast. As users join or leave multicast groups, data is broadcast to each router in the internetwork. The routers prune out the users who do not want further transmissions.

Distance Vector Multicast Routing Protocol. The first protocol that was developed to support multicast routing is called Distance Vector Multicast Routing Protocol (DVMRP), described in RFC 1075. It is used extensively on the MBONE. The approach used by DVMRP is to assume initially that every host on the network is part of the multicast group. Multicast messages are transmitted over every possible router interface as they proceed across the network, forming a spanning tree to all possible members of the multicast group. DVMRP maintains a current image of the network topology using a distance-vector routing protocol such as the Routing Information Protocol RIP. The distance metric used for RIP and DVMRP is the number of hops in the path.

The Distance Vector Multicast Routing Protocol is used for the communication and distribution of multicast routing table information. It is based on the RIP protocol used in unicast routing.

Distance Vector Multicast Routing Protocol. Distributed multicast routing protocol that dynamically generates IP multicast delivery trees using a technique called reverse-path multicasting (RPM) to forward multicast traffic to downstream interfaces.