Distance-vector routing protocol

A distance-vector routing protocol is one of the two major classes of routing protocols used in packet-switched networks for computer communications, the other major class being the link-state protocol. A distance-vector routing protocol uses the Bellman-Ford algorithm to calculate paths.

Examples of distance-vector routing protocols include RIPv1 and 2 and IGRP. EGP and BGP are not pure distance-vector routing protocols but their concepts are the same. In many cases, EGP and BGP are considered DV (distance-vector) routing protocols.

A distance-vector routing protocol requires that a router informs its neighbors of topology changes periodically and, in some cases, when a change is detected in the topology of a network. Compared to link-state protocols, which requires a router to inform all the nodes in a network of topology changes, distance-vector routing protocols have less computational complexity and message overhead.

Reference:
http://en.wikipedia.org/wiki/Distance-vector_routing_protocol