Cisco IE-4000 Software Configuration Manual page 866

Configuring IP Unicast Routing
Configuring BGP
DETAILED STEPS
Command
1. configure terminal
2. ip community-list
community-list-number {permit |
deny} community-number
3. router bgp autonomous-system
4. neighbor {ip-address | peer-group
name} send-community
5. set comm-list list-num delete
6. exit
7. ip bgp-community new-format
8. end
9. show ip bgp community
10. copy running-config
startup-config
EXAMPLE
In the following example, a standard community list is configured that permits routes from network 10 in autonomous
system 50000:
Router(config)# ip community-list 1 permit 50000:10
In the following router configuration mode example, the router belongs to autonomous system 109 and is configured to
send the communities attribute to its neighbor at IP address 172.16.70.23:
Switch(config)# router bgp 109
Switch(config-router)# neighbor 172.16.70.23 send-community
In the following example, a router that uses the 32-bit number community format is upgraded to use the AA:NN format:
Switch(config)# ip bgp-community new-format
The following sample output shows how BGP community numbers are displayed when the ip bgp-community
new-format command is enabled:
Switch# show ip bgp 10.0.0.0
BGP routing table entry for 10.0.0.0/8, version 4
Paths: (2 available, best #2, table Default-IP-Routing-Table)
Advertised to non peer-group peers:
10.0.33.35
Purpose
Enter global configuration mode.
Create a community list, and assign it a number.

The community-list-number is an integer from 1 to 99 that
identifies one or more permit or deny groups of
communities.

The community-number is the number configured by a set
community route-map configuration command.
Enter BGP router configuration mode.
Specify that the COMMUNITIES attribute be sent to the
neighbor at this IP address.
(Optional) Remove communities from the community attribute
of an inbound or outbound update that match a standard or
extended community list specified by a route map.
Return to global configuration mode.
(Optional) Display and parse BGP communities in the format
AA:NN.
A BGP community is displayed in a two-part format 2 bytes
long. The Cisco default community format is in the format
NNAA. In the most recent RFC for BGP, a community takes the
form AA:NN, where the first part is the AS number and the
second part is a 2-byte number.
Return to privileged EXEC mode.
Verify the configuration.
(Optional) Save your entries in the configuration file.
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