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.
By default, no matching is performed.
Tabl e 101 Defining If-match Conditions
Operation Command
Match the destination address of the routing
information
if-match { acl | ip-prefix }
Cancel the matched destination address of the
routing information set by the ACL
undo if-match [ acl acl-number |
ip-prefix ip-prefix-name ]
Match the next-hop interface of the routing
information
if-match interface {
interface-type interface-number }
Cancel the matched next-hop interface of the
routing information
undo if-match interface
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
information set by the address prefix list
undo if-match ip next-hop [
ip-prefix ip-prefix-name ]
Match the tag domain of the routing
information
if-match tag value
Cancel the tag domain of the matched
routing information
undo if-match tag