3Com 10014299 manual RIP Overview

28 CONFIGURING RIP

	This chapter covers the following topics:
	■	RIP Overview
	■	Configure RIP
	■ Displaying and Debugging RIP
	■ RIP - Unicast Configuration Example
	■	Troubleshooting RIP
RIP Overview	The Routing Information Protocol (RIP) is an interior gateway and dynamic routing
	protocol based on the Distance-Vector (D-V) routing algorithm. RIP uses User
	Datagram Protocol (UDP) packets to exchange routing information and adopts

hop count to measure the distance from the destination, called the routing cost. In RIP, a hop count that is equal to or larger than 16 is defined as infinity (the destination network or host is unreachable) so RIP is generally applied to medium-sized networks, such as a campus network. RIP is not designed for complicated and large-sized networks.

RIP has two versions, RIP-1 and RIP-2. RIP-2 supports simple text authentication and MD5 authentication, as well as the variable-length sub-net masks.

To improve performance and prevent route loops, RIP supports split-horizon, poisoned reverse using triggered update. This allows the importation of routes that are obtained by other routing protocols.

Each router that runs RIP manages a database that includes route items of all reachable routers on the network. A route item includes the following information.

■ Destination address: The address of the host or network.

■ Next-hop address: The address of the next router through which this route passes to get to the destination.

■ Interface: The interface where messages are forwarded.

■ Metric value: The overhead for the router to get to the destination. It is an integer ranging from 0 to16.

■ Timer: The last time the route item was modified.

■ Route tag: The tag indicates whether it is an internal routing protocol route or an external routing protocol route.