3Com Switch 7750 Configuration Guide Guide

276 CHAPTER 33: RIP CONFIGURATION
■ Timeout timer: If a RIP route is not updated (that is, the switch does not receive
any routing update packet from the neighbor) within the timeout time of this
timer, the route is considered unreachable.
■ Garbage-collection timer: An unreachable route will be completely deleted
from the routing table if no update packet for the route is received from the
neighbor before this timer times out.
RIP Startup and
Operation
The whole process of RIP startup and operation is as follows:
■ Once RIP is enabled on a router, the router broadcasts or multicasts a request
packet to its neighbors. Upon receiving the packet, each neighbor running RIP
answers a response packet containing its routing table information.
■ When this router receives a response packet, it modifies its local routing table
and sends an update triggering packet to the neighbor. Upon receiving the
update triggering packet, the neighbor sends the packet to all its neighbors.
After a series of update triggering processes, each router can get and keep the
updated routing information.
■ By default, RIP sends its routing table to its neighbors every 30 seconds. Upon
receiving the packets, the neighbors maintain their own routing tables and
select optimal routes, and then advertise update information to their respective
neighbors so as to make the updated routes known globally. Furthermore, RIP
uses the timeout mechanism to handle the timeout routes so as to ensure
real-time and valid routes.
RIP is commonly used by most IP router suppliers. It can be used in most campus
networks and the regional networks that are simple and less dispersive. For larger
and more complicated networks, RIP is not recommended.
Introduction to RIP
Configuration Tasks
Tabl e 195 RIP configuration tasks
Configuration Task Description Related section
Configuring Basic RIP
Functions
Enabling RIP globally
and on the interface
of a specified network
segment
Required
“Enabling RIP globally
and on the interface
of a specified network
segment”
Setting the RIP
operating status on
an interface
Optional
“Setting the RIP
operating status on
an interface”
Specifying the RIP
version on an
interface
Optional
“Specifying the RIP
version on an
interface”