Routing Policy Application; Routing Policy Configuration Task List; Defining Filtering Lists; Prerequisites - 3Com MSR 50 Series Configuration Manual

Routing Policy
Application
Routing Policy
Configuration Task
List

Defining Filtering Lists

Prerequisites

Defining an IP-prefix List

Each node comprises a list of if-match and apply clauses. The if-match clauses
define the match criteria. The matching objects are some attributes of routing
information. The different if-match clauses on a node is in logical AND
relationship. Only when the matching conditions specified by all the if-match
clauses on the node are satisfied, can routing information pass the node. The
apply clauses specify the actions performed after the node is passed, concerning
the attribute settings for routing information.
The filter relation among different route policy nodes is logical OR. Once a node is
matched, the routing policy is passed and the packet will not go through the next
node.
A routing policy is applied in two ways:
When redistributing routes from other routing protocols, a routing protocol
■
accepts only routes passing the routing policy.
When receiving or advertising routing information, a routing protocol uses the
■
routing policy to filter routing information.
To configure a routing policy, perform the tasks described in the following
sections:
Task
"Defining Filtering Lists" on page
993
"Configuring a Routing Policy" on
page 996
Before configuring this task, you need to decide on:
IP-prefix list name
■
Matching address range
■
Extcommunity list sequence number
■
Define an IPv4 prefix list
Identified by name, each IPv4 prefix list can comprise multiple items. Each item
specifies a matching address range in the form of network prefix identified by
index number.
During matching, the system compares the route to each item identified by index
number in the ascending order. If one item matches, the route passes the IP-prefix
list, without needing to match against the next item.

Routing Policy Configuration Task List

"Defining an IP-prefix List" on page 993
"Defining an AS Path ACL" on page 995
"Defining a Community List" on page 995
"Defining an Extended Community List" on page 995
"Creating a Routing Policy" on page 996
"Defining if-match Clauses for the Routing Policy" on
page 996
"Defining apply Clauses for the Routing Policy" on page
998
993