Filters; Route Policy Application; Route Policy Configuration Task List - 3Com 4500G Family Configuration Manual

Filters

There are six types of filters: ACL, IP prefix list, and route policy.
ACL
ACL involves IPv4 ACL and IPv6 ACL. An ACL is configured to match the destinations or next hops of
routing information.
For ACL configuration, refer to ACL configuration in the Security Volume.
IP prefix list
IP prefix list involves IPv4 and IPv6 prefix list.
An IP prefix list is configured to match the destination address of routing information. Moreover, you can
use the gateway option to allow only routing information from certain routers to be received. For
gateway option information, refer to RIP Commands in the IP Routing Volume.
An IP prefix list, identified by name, can comprise multiple items. Each item, identified by an index
number, can specify a prefix range to match. An item with a smaller index number is matched first. If one
item is matched, the IP prefix list is passed, and the packet will not go to the next item.
Route policy
A route policy is used to match routing information and modify the attributes of permitted routes. It can
reference the above mentioned filters to define its own match criteria.
A route policy can comprise multiple nodes, which are in logic OR relationship. Each route policy node
is a match unit, and a node with a smaller number is matched first. Once a node is matched, the route
policy is passed and the packet will not go to the next node.
A route policy node comprises a set of if-match and apply clauses.
The if-match clauses define the match criteria. The matching objects are some attributes of routing
information. The if-match clauses of a route policy node is in logical AND relationship. That is, a
packet must match all the if-match clauses of the node to pass it.
The apply clauses of the node specify the actions to be taken on the permitted packets, such as
route attribute modification.
Follow these guidelines for configuring if-match and apply clauses.
If you want to implement route filtering only, you do not need to configure apply clauses.
If you do not configure any if-match clauses for a permit-mode node, the node permits all routes to
pass.
Configure a permit-mode node containing no if-match or apply clauses behind multiple
deny-mode nodes to allow unmatched routes to pass.

Route Policy Application

A route policy is applied on a router to filter routes when they are received, advertised or redistributed
and to modify some attributes of permitted routes.

Route Policy Configuration Task List

Complete the following tasks to configure a route policy:
1-2