BGP Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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Removal of link-bandwidth extended community to iBGP peers

Updated: February 28, 2026

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Overview

Explains the removal of link-bandwidth extended community to iBGP peers to minimize exposure of DMZ community parameters and enable proportional traffic distribution over multiple iBGP paths.

The removal of link-bandwidth extended community to iBGP peers is a feature that:

  • minimizes the risk of exposing DMZ link-bandwidth community parameters to network zones where they are not recognized or necessary

  • allows BGP to send traffic over multiple internal BGP (iBGP) learned paths, and

  • sends traffic proportional to the bandwidth of the links used to exit the autonomous system.

Table 1. Feature History Table

Feature Name

Release Information

Feature Description

Removal of Link-Bandwidth Extended Community to iBGP Peers

 Release 7.3.2

The demilitarized zone (DMZ) link-bandwidth extended community allows BGP to send traffic over multiple internal BGP (iBGP) learned paths. The traffic that is sent is proportional to the bandwidth of the links that are used to exit the autonomous system. By default, iBGP propagates DMZ link-bandwidth community. This feature minimizes the risk of exposure of the community parameters, which are used to control the routing policy in the service provider network, to networks zones where they are not recognized or not required.

By default, iBGP propagates DMZ link-bandwidth community. This feature minimizes the risk of exposing community parameters, which control the routing policy in the service provider network, to network zones where they are not recognized or required.

Configure route policy to remove extended communities

Configure a route policy to remove extended communities.

This task provides examples of how to configure route policies to remove extended communities, either all of them or specific ones.

Procedure

1.

Choose one of these steps to configure a route policy to remove extended communities

  • Configure a route policy to delete all extended communities.

    Router(config)# route-policy dmz_del_all 
Router(config-rpl)# delete extcommunity bandwidth all
Router(config-rpl)# pass
Router(config-rpl)# end-policy

  • Configure a route policy to delete only the extended communities that match an extended community mentioned in a list.

    Router(config)# route-policy dmz_CE1_del_non_match
Router(config-rpl)# if destination in (10.9.9.9/32) then 
Router(config-rpl-if)# delete extcommunity bandwidth in (10:7000) 
Router(config-rpl-if)# endif
Router(config-rpl)# pass
Router(config-rpl)# end-policy

  • Configure a route policy to delete all extended communities using parameters.

    Router(config)# route-policy dmz_del_param2($a,$b) 
Router(config-rpl)# if destination in (10.9.9.9/32) then
Router(config-rpl-if)# delete extcommunity bandwidth in ($a:$b)
Router(config-rpl-if)# endif 
Router(config-rpl)# pass 
Router(config-rpl)# end-policy
2.

Run show bgp command to confirm the BGP routing table entries and extended community attributes.

Example:

Router# show bgp 10.9.9.9/32

BGP routing table entry for 10.9.9.9/32
Versions:
Process bRIB/RIB SendTblVer
Speaker 15 15
Last Modified: Aug 27 13:06:45.000 for 00:08:21
Paths: (3 available, best #1)
Advertised IPv4 Unicast paths to peers (in unique update groups):
13.13.13.5
Path #1: Received by speaker 0
Advertised IPv4 Unicast paths to peers (in unique update groups):
13.13.13.5
10
10.10.10.1 from 10.10.10.1 (192.168.0.1)
Origin incomplete, metric 0, localpref 100, valid, external, best, group-best, multipath
Received Path ID 0, Local Path ID 1, version 15
Extended community: LB:10:48
Origin-AS validity: (disabled)
Path #2: Received by speaker 0
Not advertised to any peer
10
11.11.11.3 from 11.11.11.3 (192.168.0.3)
Origin incomplete, metric 0, localpref 100, valid, external, multipath
Received Path ID 0, Local Path ID 0, version 0
Extended community: LB:10:48
Origin-AS validity: (disabled)
Path #3: Received by speaker 0
Not advertised to any peer
10
12.12.12.4 from 12.12.12.4 (192.168.0.4)
Origin incomplete, metric 0, localpref 100, valid, external, multipath
Received Path ID 0, Local Path ID 0, version 0
Extended community: LB:10:48
Origin-AS validity: (disabled)

22:35 30-09-2021