The Distance Vector algorithm sets distance as a metric based on the number of hops. Bandwidth or delay would also be theoretically possible as metrics, but are rarely implemented in practice. In principle, all routers are considered equal and are not differentiated with regard to their position in the overall network. The underlying router topology has a completely flat structure. The distance- vector algorithm, also called the Bellman-Ford algorithm after the developer of such a method, uses distributed computation, with each router sending its complete routing table to all other routers when a change is noticed and/or at intervals.
Since when such a network is put into operation or when a router is inserted, it does not know its direct neighbors, it relies on the information from the neighboring routers. Based on the information about the links and the hops or costs, the router can build its routing table. Typical DVA protocols are the well-known Routing Information Protocol( RIP), Gateway to Gateway Protocol( GGP), Interior Gateway Protocol( IGRP) and Enhanced Interior Gateway Protocol( EIGRP).