Cisco Cisco Packet Data Interworking Function (PDIF)
Routing
▀ BGP-4 Routing
▄ ASR 5500 System Administration Guide, StarOS Release 16
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Setting the Community Attribute
You set the BGP community attribute via a set community command in a route map.
config
context context_name
route-map map_name { deny | permit } sequence_number
set community [additive]{ internet | local-AS | no-advertise | no-export
| none | value AS-community_number AS-community_number AS-community_number ...}
| none | value AS-community_number AS-community_number AS-community_number ...}
{ internet | local-AS | no-advertise | no-export | none | value AS-
community_number AS-community_number AS-community_number ... }
community_number AS-community_number AS-community_number ... }
{ internet | local-AS | no-advertise | no-export | none | value AS-
community_number AS-community_number AS-community_number ... }
community_number AS-community_number AS-community_number ... }
The additive option allows you to enter multiple destinations and AS community numbers. For additional information,
see the Command Line Interface Reference.
see the Command Line Interface Reference.
Filtering via a BGP Community
To filter routes based on a BGP community, you configure a match clause in a route map. The command sequence
follows below.
follows below.
config
context context_name
route-map map_name { deny | permit } sequence_number
match community { named named_list | standard identifier }
BGP Extended Communities
Configuring a BGP Extended Community (Route Target)
A BGP extended community defines a route target. MPLS VPNs use a 64-bit Extended Community attribute called a
Route Target (RT). An RT enables distribution of reachability information to the correct information table.
Route Target (RT). An RT enables distribution of reachability information to the correct information table.
You configure a BGP extended community via a Context Configuration mode command.
config
context context_name
ip extcommunity-list { named named_list | standard identifier } { deny |
permit } rt rt_number rt_number rt_number ...
permit } rt rt_number rt_number rt_number ...
rt_number
specifies a Route Target as a string in AS:NN format, where AS = 2-byte AS-community hexadecimal
number and NN = 2-byte hexadecimal number (1 to 11 characters). You can add multiple route numbers to an IP
extcommunity list.
extcommunity list.