3Com 10014299 manual IP Routing Policy

31 CONFIGURING IP ROUTING POLICY

	This chapter covers the following topics:
	■ IP Routing Policy Overview
	■ Configure IP Routing Policy
	■ Displaying and Debugging IP Routing Policy
	■ Configuring IP Routing Policy
	■ Troubleshooting IP Routing Policy
IP Routing Policy	During the information exchange with a peer router, the routing protocol may
Overview	need to receive or distribute only part of the route information that complies with
	specific conditions; and to import only part of the route information learned by
	other protocols that satisfy the preset conditions. In addition, some attributes of
	the imported route information are set in order to satisfy the requirements of the
	protocol. The route strategy also provides measures for the routing protocol to
	implement these functions.
	The route strategy consists of a series of rules, classified into three types and used
	for route information filtering in route advertisement, route receiving, and route
	import. Since defining a strategy is similar to defining a group of filters that are
	used during receiving or advertising route information or before the route
	information exchange between different protocols, route strategy is also called
	route filtering.
	A common filter is the basis for route strategy implementation. The user defines
	some matching conditions as necessary, which are referred to when making the
	routing strategies. Apply these conditions to different objects such as the
	destination address of the routing information, and the router address publishing
	the routing information, to implement route information filtering.

A routing strategy provides five filters:

1Routing policy

2Access list

3Aspath-list

4Community-list

5Prefix-list

These filters serve as the reference for the protocols to work out routing strategies.