RIP (Routing Information Protocol)
is a distance-vector routing protocol. It's been around for years and is no longer used very much. It's a protocol used by routing nodes to exchange network information. Each node that supports RIP advertises all the networks it knows about, typically every 30 seconds, using one or more broadcast packets. RIP can be used to route IP, IPX, and other protocols.
Routing tables are stored by each node supporting RIP. As advertisements from other RIP nodes are received, the routes to networks are added to the table. The route that gets stored is via the router that is closest, based on the number of hops away it is (the distance). It's simplest to think of a hop as another RIP router.
Routes can appear and disappear in a network as outages invariably happen. A RIP router will age out a route if it stops receiving advertisements for it from other RIP routers. This process can take several minutes, depending on the configuration, so RIP is not the most desirable routing protocol to use. High availability is not in it's vocabulary!