3com DUA1750-2BAA01 Manual De Usuario

3Com Switch 8800 Configuration Guide 

Chapter 18  RIP Configuration

 

18-1 

Routing Information Protocol (RIP) is a relatively simple interior gateway protocol (IGP), 

which is mainly applied to small scale networks. 

It is easy to implement RIP. You can configure and maintain RIP more easily than OSPF 

and IS-IS, so RIP still has a wide application in actual networking. 

RIP is a kind of Distance-Vector (D-V) algorithm-based protocol and exchanges routing 

information via UDP packets. 

It employs Hop Count to measure the distance to the destination host, which is called 

Routing Cost. 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 value is an integer ranging 

from 0 to 15. The hop count equal to or exceeding 16 is defined as infinite, that is, the 

destination network or the host is unreachable. 

To improve the performance and avoid route loop, RIP supports Split Horizon and 

allows importing the routes discovered by other routing protocols. 

Each router running RIP manages a route database, which contains routing entries to 

all the reachable destinations in the network. These routing entries contain the 

following information: 

z 

Destination address: IP address of a host or a network. 

z 

Next hop address: The interface address of the next router that an IP packet will 

pass through for reaching the destination. 

z 

Output interface: The interface through which the IP packet should be forwarded. 

z 

Cost: The cost for the router to reach the destination, which should be an integer in 

the range of 0 to 16. 

z 

Timer: Duration from the last time that the routing entry is modified till now. The 

timer is reset to 0 whenever a routing entry is modified. 

In RFC1058, RIP is controlled by the following timers: Period update, Timeout and 

Garbage-Collection.