Routing Policy Configuration Task List 417
order of node sequence number. Once a node is matched, the routing policy is
passed and the packet will not go through the next node.
Each 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 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 to be performed after the node is passed,
concerning the attribute settings for routing information.
Routing Policy
Application
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.
Routing Policy
Configuration Task
List
Complete the following tasks to configure a routing policy:
Defining Filtering Lists
Prerequisites Before configuring this task, you need to decide on:
■ IP-prefix list name
■ Matching address range
■ Extcommunity list sequence number
Defining 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.
Follow these steps to define an IPv4 prefix list:
Task
“Defining Filtering Lists” on page
417
“Defining an IPv4 prefix List” on page 417
“Defining an AS Path List” on page 418
“Defining a Community List” on page 418
“Defining an Extended Community List” on page 419
“Configuring a Routing Policy” on
page 419
“Creating a Routing Policy” on page 419
“Defining if-match Clauses for the Routing Policy” on
page 420
“Defining apply Clauses for the Routing Policy” on page
421
To Next Page
Loading...
