Editing Distance-vector routing protocol (section)

==Methodology==
Routers that use distance-vector protocol determine the distance between themselves and a destination. The best route for [[data]] through a [[data network]] is measured in terms of the numbers of [[Router (computing)|routers]] (hops) a packet has to pass through to reach its destination network. Additionally, some distance-vector protocols take into account other traffic information, such as [[network latency]]. To establish the best route, routers regularly exchange information with neighbouring routers, usually their [[routing table]], hop count for a destination network and possibly other traffic related information. Routers that implement distance-vector protocol rely purely on the information provided to them by other routers, and do not assess the [[network topology]].<ref>{{Cite book|title= Network+ Guide to Networks|url= https://archive.org/details/networkguidetone00dean_142|url-access= limited|author =Tamara Dean |publisher= Cengage Learning|year=2009 |isbn=  9781423902454|pages=[https://archive.org/details/networkguidetone00dean_142/page/n294 274]}}</ref>

Distance-vector protocols update the routing tables of routers and determine the route on which a packet will be sent by the ''next hop'' which is the exit interface of the router and the IP address of the interface of the receiving router. Distance is a measure of the cost to reach a certain node. The least cost route between any two nodes is the route with minimum distance.

Updates are performed periodically in a distance-vector protocol where all or part of a router's routing table is sent to all its neighbours that are configured to use the same distance-vector routing protocol. Once a router has this information it is able to amend its own routing table to reflect the changes and then inform its neighbours of the changes. This process has been described as ‘routing by rumour’ because routers are relying on the information they receive from other routers and cannot determine if the information is actually valid and true. There are a number of features which can be used to help with instability and inaccurate routing information.