Bgp Communities And Extended Communities - Cisco ASR 5000 Series Administration Manual

Routing
• The redistribution options are connected, ospf, rip, or static. Refer to the Border Gateway Protocol
• A maximum of 64 route-maps are supported per context.
• Save your configuration as described in the Verifying and Saving Your Configuration chapter.

BGP Communities and Extended Communities

Route filtering based on a BGP community or extended community (route target) is configured via CLI Route
Map Configuration mode commands.
BGP Communities
Configuring a BGP Community
A BGP community is a group of destinations that share some common attribute. Each destination can belong
to multiple communities. Autonomous system administrators define to which communities a destination
belongs.
You configure a BGP community via a Context Configuration mode command.
config
context context_name
ip community-list { named named_list | standard identifier } { deny | permit } { internet | local-AS
| no-advertise | no-export | value AS-community_number AS-community_number AS-community_number
...}
AS-community_number AS-community_number ...}
AS-community_number AS-community_number ...}
You can permit or deny the following BGP community destinations.
• internet – Advertise this route to the internet community, and any router that belongs to it.
• local-AS – Use in confederation scenarios to prevent sending packets outside the local autonomous
• no-advertise – Do not advertise this route to any BGP peer, internal or external.
• no-export – Do not advertise to external BGP (eBGP) peers. Keep this route within an AS.
• value AS-community_number – Specifies a community string in AS:NN format, where AS = 2-byte
You can enter multiple destinations and AS community numbers for each community. For additional
information, see the Command Line Interface Reference.
Multiple community-list entries can be attached to a community-list by adding multiple permit or deny clauses
for various community strings. Up to 64 community-lists can be configured in a context.
Configuration Mode Commands chapter of the Command Line Interface Reference for details on the
redistribute command.
{ internet | local-AS | no-advertise | no-export | value AS-community_number
{ internet | local-AS | no-advertise | no-export | value AS-community_number
system (AS).
AS-community hexadecimal number and NN = 2-byte hexadecimal number (1 to 11 characters).
BGP Communities and Extended Communities
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