Routing Information Protocol

aliases:

A distance-vector routing protocol.

RIP only considers a single metric: the next hop router. It chooses paths based on the minimum hop distance to the destination router. Even while it's no longer widely deployed, it's used to compare it's basic algorithmic approach to more modern, complex routing protocols.

RIP sends regular updates (about every 30 seconds) to neighboring routers about it's entire routing database. It also sends updates when triggered by a network topology change. When receiving a routing update from a neighbor, RIP checks the hop count, updating it's own routing table if the hop count is lower than the one it already has stored. It then increments the hop count, and sets the neighbor as the next hop to the newly discovered networks.

RIP typically sets the maximum hop count as 15 to avoid looping. However, this limits the size of networks that use RIP to 15 as well, since routers that have a hop count of 16 or more are undiscoverable by RIP.\