Foundry Networks AR1216, AR3202 Configure policy aspath, Parameter Description, Syntax, Example

Foundry AR-Series Router User Guide

configure policy as_path

This command configures the autonomous system path filter for BGP.

AS path access lists are used for matching the AS path attribute in a BGP route. An AS path access list succeeds if any “permit” line in the list matches, or fails if any “deny” line matches. Matching proceeds sequentially and stops at the first match.

The regular expression parameter is an as path regular expression. (For regular expression syntax, see “AS Path Regular Expressions” on page 13-1.) Note that the regular expression must be enclosed in quotation marks. The AS number is the smallest element of a Foundry regular expression. It is an integer ranging from 0 to 65536; the Foundry regular expression matcher is AS number-based.

Any number of AS path access list lines may be declared. They are evaluated in the order declared. If neither permit nor deny is specified, the default is “permit.”

Parameter	Description
access_list	Access list number
	Range is 1 - 199.
number	Sequence to insert or delete from an existing AS path entry.
	Range is 0 - 65535.
action
deny	Deny AS path.
permit	Permit AS path.
regular_expression	Regular expression to match the AS paths.
	Enter a quoted string.
	Refer to “AS Path Regular Expressions” on page 13-1for more
	information about regular expressions.

syntax:

[ no ] policy as_path access_list < n > number < n > action < deny permit > regular_expression < “string” >

example:

Foundry-AR1208/configure#policy as_path 1 120 permit “100”

example:

Foundry-AR1208/configure#policy as_path 1 121 deny “.* 101 .*”

applicable systems:

All models.

3 - 2 © 2004 Foundry Networks, Inc. June 2004