3Com 4510G - Route Policy Application; Route Policy Configuration Task List; Defining Filters; Prerequisites

6-2
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.
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:
Task
Defining Filters Defining an IP-prefix List
Creating a Route Policy
Defining if-match Clauses
Configuring a Route Policy
Defining apply Clauses
Defining Filters
Prerequisites
Before configuring this task, you need to decide on:
z IP-prefix list name
z Matching address range