Cisco Cisco Packet Data Interworking Function (PDIF)
Routing
▀ BGP-4 Routing
▄ ASR 5000 System Administration Guide, StarOS Release 18
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Multiple extended community-list entries can be attached to an extended community-list by adding multiple permit or
deny clauses for various extended community strings. Up to 64 extended community-lists can be configured in a
context.
deny clauses for various extended community strings. Up to 64 extended community-lists can be configured in a
context.
Setting the Extended Community Attribute
You set the BGP extended community attribute via a set extcommunity command in a route map.
config
context context_name
route-map map_name { deny | permit } sequence_number
set extcommunity 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.
Filtering via a BGP Extended Community
To filter routes based on a BGP extended community (route target), you configure a match clause in a route map. The
command sequence follows below.
command sequence follows below.
config
context context_name
route-map map_name { deny | permit }
[no] match extcommunity { named named_list | standard identifier }
BGP Local Preference
The BGP local preference attribute is sent by BGP speaker only to IBGP peers. It is set in a route map via the following
command sequence:
command sequence:
config
context context_name
route-map map_name { deny | permit }
set local-preference pref_number
There is no match clause corresponding to local preference in the route-map because local-preference is directly used in
the route selection algorithm.
the route selection algorithm.