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Configuring the Extended Communities Attribute

To configure extended communities, include the community statement:




community name {
invert-match;
members [ community-ids ]; 
}

You can include this statement at the following hierarchy levels:

[edit policy-options]
[edit logical-systems logical-system-name policy-options]

To include the community in a routing policy, include the community condition in the from statement at the [edit policy-options policy-statement policy-name term term-name] hierarchy level:



[edit policy-options] 

community name members [ community-ids ]; 

policy-statement policy-name {


term term-name {


from {
community name; 
}


}


}

name identifies one or more routers in the BGP extended community.

community-ids identifies the type of extended community in the following format:




type:administrator:assigned-number

type is the type of extended community and can be either a bandwidth, target, origin, domain-id, src-as, rt-import community, or a 16-bit number that identifies a specific BGP extended community. The bandwidth community sets up the bandwidth extended community. The target community identifies the destination to which the route is going. The origin community identifies where the route originated. The domain-id community identifies the Open Shortest Path First (OSPF) domain from which the route originated. The src-as community identifies the autonomous system from which the route originated. The rt-import community identifies the route to install in the routing table.

Note: For src-as, you can specify only an AS number and not an IP address. For rt-import, you can specify only an IP address and not an AS number.

administrator is the administrator. It is either an AS number or an IP version 4 (IPv4) address prefix, depending on the type of extended community.

assigned-number identifies the local provider.

Beginning with JUNOS Release 9.1, the AS number range has been extended to provide BGP support for 4-byte AS numbers as defined in RFC 4893, BGP Support for Four-octet AS Number Space. In plain-number format, you can configure a value in the range from 1 through 4,294,967,295. To configure an extended community for a target or an origin that includes a 4-byte AS number in the plain-number format, you must append the letter “L” to the end of number. For example, to configure a target for the 4-byte AS number 334,324 with an assigned number of 132, include the following statement: target:334324L:132.

Beginning with JUNOS Release 9.2, you can also configure a 4-byte AS number using the AS-dot notation format of two integer values joined by a period: <16-bit high-order value in decimal>.<16-bit low-order value in decimal>. For example, the 4-byte AS number of 65546 in plain-number format is represented as 1.10 in the AS-dot notation format. The target and origin extended communities support the AS-dot notation format for 4-byte AS numbers.

For information about the community attribute, see Configuring the Community Attribute.

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