Allied Telesis VERSION 5.4.3-2.6, BGP4 manual Set as-path Route Map, Prepend

BGP and BGP4+ Commands

set as-path (Route Map)

Use this command to add an AS path set clause to a route map entry.

When a BGP update message matches the route map entry, the device prepends the specified Autonomous System Number (ASN) or ASNs to the update’s AS path attribute.

The AS path attribute is a list of the autonomous systems through which the announcement for the prefix has passed. As prefixes pass between autonomous systems, each autonomous system adds its ASN to the beginning of the list. This means that the AS path attribute can be used to make routing decisions.

Use the no variant of this command to remove the set clause.

Syntax set as-path prepend <1-65535> [<1-65535>]...

no set as-path prepend [<1-65535> [<1-65535>]...]

Parameter Description

prepend Prepends the autonomous system path.

<1-65535>The number to prepend to the AS path. If you specify multiple ASNs, separate them with spaces.

Mode Route-map mode

Usage Use the set as-pathcommand to specify an autonomous system path. By specifying the length of the AS-Path, the device influences the best path selection by a neighbor. Use the prepend parameter with this command to prepend an AS path string to routes increasing the AS path length.

This command is valid for BGP update messages only.

Example To use entry 3 of the route map called myroute to prepend ASN 8 and 24 to the AS path of matching update messages, use the commands:

awplus# configure terminal awplus(config)# route-map myroute permit 3

awplus(config-route-map)# set as-path prepend 8 24

Related Commands match as-path (Route Map) route-map (Route Map) show route-map (Route Map)

	Software Reference Supplement for SwitchBlade® x8112, x908, x900 and x610 Series Switches
C613-50032-01 REV D	AlliedWare PlusTM Operating System - Software Version 5.4.3-2.6	3.203