3-1
3 RIP Configuration
When configuring RIP, go to these sections for information you are interested in:
z RIP Overview
z RIP Configuration Task List
z RIP Configuration Example
z Troubleshooting RIP Configuration
The term router in this chapter refers to a router in a generic sense or an Ethernet switch running a
routing protocol.
RIP Overview
Routing information protocol (RIP) is a simple interior gateway protocol (IGP) suitable for small-sized
networks. RIP is not recommended in complicated large networks.
Basic Concepts
RIP
RIP is a distance-vector (D-V) algorithm–based protocol. It uses port 520 to exchange routing
information through UDP packets.
RIP uses hop count (also called routing cost) to measure the distance to a destination address. In RIP,
the hop count from a router to its directly connected network is 0, and that to a network which can be
reached through another router is 1, and so on. To restrict the time to converge, RIP prescribes that the
cost is an integer ranging from 0 and 15. The hop count equal to or exceeding 16 is defined as infinite;
that is, the destination network or host is unreachable. This limitation makes RIP not suitable for large
networks.
To improve performance and avoid routing loop, RIP supports split horizon. Besides, RIP can import
routes discovered by other routing protocols.
RIP routing database
Each RIP router has a routing table containing routing entries of all reachable destinations, and each
routing entry contains:
z Destination address: IP address of a host or network.
z Next hop: IP address of an interface on the adjacent router that IP packets should pass through to
reach the destination.