Overview of RIP

The Routing Information Protocol (RIP) applies to small and simply structured networks. RIP is a routing protocol based on the distance vector and uses hop counts to measure distances to destinations. There are two RIP versions: RIP-1 and RIP-2.

Definition

RIP is a simple Interior Gateway Protocol (IGP) and works based on the Distance-Vector (DV) algorithm. It exchanges routing information using User Datagram Protocol (UDP) packets. RIP uses port 520.

To prevent routing loops:

RIP employs Hop Count (HC) to measure distances to destinations. The distance is called the metric value. RIP defines that the default HC from a router to its directly connected network is 0, and the HC from a router to a reachable network through another router is 1, and so on. This means that the HC is equal to the number of routers passed from the local network to the destination network. To speed up route convergence, RIP defines the HC as an integer that ranges from 0 to 15. The HC equal to or greater than 16 is defined as infinity, which indicates that the destination network or the host is unreachable. RIP does not apply to large networks.
RIP supports split horizon and poison reverse.

Objective

As an earliest IGP, RIP is used in small and simply structured networks such as campus networks and regional networks. Unlike static routes, RIP automatically adapts to network topology changes.

Implementing RIP is simple. Configuring and maintaining RIP are easier than the Open Shortest Path First (OSPF) and Intermediate System-to-Intermediate System (IS-IS) protocols. Therefore, RIP is widely used.