Configure Extcommunity-List

Configuration Condition

None

Configure an Extcommunity-List

An extended community list (Extcommunity-list) filters BGP routes based on the extended community properties. The quality and usage method of an extended community list (Extcommunity-list) are the same as a standard community list. The major difference is that extended community properties are mainly used in a Multi Protocol Label Switching (MPLS) Layer 3 Virtual Private Network (L3VPN), so an Extcommunity list is also mainly used in an MPLS L3VPN.

Two types of Extcommunity-lists are available: standard Extcommunity-list and extended Extcommunity-list. The standard Extcommunity-list filters BGP routes based on Router Target and Site or Origin properties. An extended Extcommunity-list filters BGP routes with community properties based on a regular expression.

An Extcommunity-list contains multiple entries, and the entries are in the OR relation. When a route tries to match an Extcommunity-list, it checks the entries following the sequence of configuration. Once the route matches an entry, it passes the filtration of the Extcommunity-list. For the use of a regular expression in configuring an extended Extcommunity-list, refer to "Configure an AS-PATH List".

Table 15-6 Configure an extcommunity-list