DVMRP is a distance vector routing protocol. DVMRP routing information is carried inside of IGMP (IP protocol 2) packets. The protocol is based on forwarding packets: the router generates a routing table with the multicast group of which it has knowledge with corresponding distances. DVMRP operates via a reverse path flooding technique, sending a copy of a received packet out through each interface except the one at which the packet arrived.
For neighbor discovery
For route exchange
For pruning multicast delivery trees
For grafting multicast delivery trees
For acknowledging graft messages
For requesting neighbor list
For responding with neighbor list