3Com 10014298 manual IP Prefix, Defining a Route Policy, Permit deny node, Undo route-policy

100CHAPTER 5: IP ROUTING PROTOCOL OPERATION

Configuring an IP Routing Policy

A basic ACL is usually used for routing information filtering. When the user defines the ACL, the user defines the range of an IP address, subnet for the destination network segment address, or the next-hop address of the routing information. If an advanced ACL is used, perform the matching operation by the specified source address range. Layer-2 ACLs

IP Prefix

The function of the ip-prefix is similar to that of the acl, but it is more flexible and easier for users to understand. When the ip-prefix is applied to routing information filtering, its matching objects are the destination address information, and the domain of the routing information. In addition, in the ip-prefix, you can specify the gateway options and require it to receive only the routing information distributed by certain routers.

An ip-prefix is identified by the ip-prefix name. Each ip-prefix can include multiple list items, and each list item can specify the match range of the network prefix forms, and is identified with a index-number. The index-number designates the matching check sequence in the ip-prefix.

During the matching, the router checks list items identified by the sequence-number in ascending order. Once a single list item meets the condition, it means that it has passed the ip-prefix filtering and does not enter the testing of the next list item.

Configuring a routing policy includes tasks described in the following sections:

■Defining a Route Policy

■Defining If-match Clauses for a Route Policy

■Defining Apply Clauses for a Route Policy

■Importing Routing Information Discovered by Other Routing Protocols

■Defining IP Prefix

■Configuring for Filtering Received Routes

■Configuring for Filtering Distributed Routes

■Displaying and Debugging the Routing Policy

Defining a Route Policy

A route policy can include multiple nodes. Each node is a unit for the matching operation. The nodes are tested again by sequence-number.

Perform the following configurations in system view.

Table 100 Defining a Route Policy

Operation	Command
Enter Route policy view	route-policyroute-policy-name {
	permit deny } node {
	node-number }
Remove the specified route-policy	undo route-policy
	route-policy-name [ permit deny
	node node-number ]