Foundry Networks AR3202-CL - Manual (Page 25)

Foundry AR-Series Router User Guide
3 - 2 © 2004 Foundry Networks, Inc. June 2004
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
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.
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 13-1 for more
information about regular expressions.