ADTRAN 5000 Series local-as <as-number>

Command Reference Guide BGP Neighbor Configuration Command Set

local-as <as-number>

Use the local-as command to specify an autonomous system (AS) number for the unit to use when commu-

nicating with this BGP neighbor. Use the no form of this command to return to default settings.

Syntax Description

<as-number>

Specifies the AS number to use when communicating with this neighbor. Must be

different than the AS number for this router and the peer router. Only valid for

eBGP connections. Range is 0 to 65,535.

Default Values

By default, no local AS number is define d. The router’s BGP AS number is used.

Applicable Platforms

This command applies to the NetVanta 300, 1000R, 2000, 3000, 4000, and 5000 and Total Access 900

Series units.

Command History

Release 9.3 Command was introduced.

Functional Notes

This command substitutes a different AS number to be used for communicating with this BGP neighbor.

(other than the on e th e ro ut er is actua lly a me m be r of ). T his ca n be use d to satisfy network desig ns

requiring a customer to appear as one AS n umber when communicating with one internet service provider

(ISP) and another when communicating with another ISP.

Usage Examples

The following example configure s this BGP neighbor’s AS number to be 300:

(config)#router bgp-neighbor 192.22.73.101

(config-bgp-neighbor)#local-as 300

Technology Review

This router appear s (to the pe er router) to be in the AS sp ecified with the local-as command. Therefore all

routes learned fr om th e p eer h ave th is nu mbe r p repen de d to th e AS path. In netwo rk adver t ise ments from

routers using the local-as command, the router’s true AS number (the number specified using the router

bgp as-number command) is prepended to the AS path attribute, and the local-AS (the number specified

in the neighbor local-as command) is prepended to the AS path attr ibute. This makes it appear that the

path to the network is first through the local-AS, and then through the true AS. To further illustrate, consider

the following example network.