Cisco® Router Configuration & Troubleshooting, Second Edition

Distance Vector—RIP

RIP is an older but still commonly used distance vector routing protocol. RIP uses broadcast UDP packets to pass routing information. The updates are sent every 30 seconds. If a router does not receive an update for 180 seconds, it marks all routes learned from that neighbor as unusable. If no updates are received for 240 seconds, all route entries learned from that neighbor are removed from the routing table. If a router receives an update for a route from the router that originally reported the route, the route is placed in a hold-down state. The route can remain in a hold-down state for a maximum of four times the update interval.

The only metric that RIP uses to determine the best path to a network is hop count. The ...