3Com 10014299 manual Configure RIP, Features is not subject to whether RIP has been enabled

414CHAPTER 28: CONFIGURING RIP

The procedure of running RIP can be described as follows:

1When a specific router is starting RIP for the first time, it broadcasts request messages to the neighbor routers. After receiving the request messages, the neighbor routers respond to the request and return response messages including local routing information.

2After receiving the response message, the router modifies the local routing table and sends triggered modified messages to the neighboring routers by broadcasting the route modification information. After receiving the triggered modified message, the neighboring routers forward them to their neighbors. After a series of triggered modification broadcasting, all routers can receive and maintain the latest routing information.

3At the same time, RIP broadcasts the local routing table to the neighbor routers every 30 seconds. The neighbor routers receive the message and maintain the local routes. Then they select the best route to broadcast the route modification information to their neighbor networks. In this way, the updated routing information can be globally effective. Also, RIP applies a timeout mechanism to dispose of an outdated route and to make sure that the route is real-time and effective.

Though RIP is widely used by most of the router manufacturers, it has limitations:

■It supports a very limited number of routers: RIP is only suitable to small autonomous systems, such as most campus networks and local networks with simple structure and high continuity.

■The route calculations depend on a fixed metric: RIP cannot update its metric in real time to adapt to network changes. The metric defined by an administrator remains constant until it is updated artificially.

■It may cost considerable network bandwidth to update its information: RIP broadcasts an update message every 30 seconds so it may cause low efficiency in a network with a lot of nodes.

Configure RIP	Begin all configuration tasks by first enabling the RIP routing process and
	associating a network with an RIP routing process, then configure other functional
	features related to RIP protocol. The task of configuring the interface-related
	features is not subject to whether RIP has been enabled.
	The original interface parameters become invalid after the RIP is closed.

Configuring RIP includes tasks described in the following sections:

■Enabling RIP

■Enabling RIP at the Specified Network

■Defining a Neighboring Router

■Specifying RIP Version

■Configuring Check Zero Field of RIP Version 1

■Specifying the Status of an Interface

■Disabling Host Routes

■Enabling Route Summarization for RIP Version 2

■Configuring RIP-2 Packet Authentication on the Interface