IP Routing Policy 101

The permit argument specifies that if a route satisfies all the if-match clauses of a node, the route passes the filtering of the node, and the apply clauses for the node are executed without taking the test of the next node. If a route does not satisfy all the if-match clauses of a node, however, the route takes the test of the next node.

The deny argument specifies that the apply clauses are not executed. If a route satisfies all the if-match clauses of the node, the node denies the route and the route does not take the test of the next node. If a route does not satisfy all the if-match clauses of the node, however, the route takes the test of the next node.

The router tests the route against the nodes in the route policy in sequence, once a node is matched, the route policy filtering is passed.

By default, the route policy is not defined.

If multiple nodes are defined in a route policy, at least one of them should be in permit mode. Apply the route policy to filter routing information. If the routing information does not match any node, the route policy denies the routing information. If all the nodes in the route policy are in deny mode, all routing information will be denied by the route policy.

Defining If-match Clauses for a Route Policy

The if-match clauses define the matching rules that the routing information must satisfy to pass the route policy. The matching objects are attributes of the routing information.

Perform the following configurations in route policy view.

Table 101 Defining If-match Conditions

Operation

Command

 

 

Match the destination address of the routing

if-match { acl ip-prefix }

information

 

Cancel the matched destination address of the

undo if-match [ acl acl-number

routing information set by the ACL

ip-prefixip-prefix-name ]

Match the next-hop interface of the routing

if-match interface {

information

interface-type interface-number }

Cancel the matched next-hop interface of the

undo if-match interface

routing information

 

Match the next-hop of the routing information

if-match ip next-hop { acl acl-number ip-prefix ip-prefix-name }

Cancel the matched next-hop of the routing

undo if-match ip next-hop [

information set by the address prefix list

ip-prefixip-prefix-name ]

Match the tag domain of the routing

if-match tag value

information

 

Cancel the tag domain of the matched

undo if-match tag

routing information

 

 

 

By default, no matching is performed.

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