DVMRP (Distance Vector Multicast Routing Protocol) is the oldest routing protocol that has been used to support multicast data transmission over networks. The protocol sends multicast data in the form of unicast packets that are reassembled into multicast data at the destination.
DVMRP can run over various types of networks, including Ethernet local area networks (LANs). It can even run through routers that are not multicast-capable. It has been considered as an intermediate solution while "real" multicast Internet Protocol (IP) routing evolves.