Juniper JUNOSE 11.2.X BGP AND MPLS, Configuration Manual

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Use to create a standard or a regular expression community list for BGP and controls
access to it.
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A route can belong to any number of communities, so a community list can have many
entries comprising many communities.
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You can specify one or more community values when you create a community list. A
clause in a route map that includes a list having more than one value only matches a
route having all of the values; that is, the multiple values are logical ANDed.
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Example
host1(config)# ip community-list 1 permit 100:2 100:3 100:4
host1(config)# route-map marengo permit 10
host1(config-route-map)# match community 1
A route matches this community list only if it belongs to at least all three communities
in community list 1: Communities 100:2, 100:3, and 100:4.
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Use the no version to remove a single community list entry if permit or deny and a
path-expression are specified. Otherwise, the entire community list is removed.
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See ip community-list.
The router supports the new BGP extended community attribute. This attribute enables
the definition of a new type of IP extended community and extended community list
unrelated to the community list that uses regular expressions. BGP speakers can use the
new extended community attribute to control routes similarly to the way it uses the
community attribute. The extended community attribute is currently defined in the Internet
draft, BGP Extended Communities Attribute—draft-ietf-idr-bgp-ext-communities-07.txt
(February 2004 expiration).
NOTE: IETF drafts are valid for only 6 months from the date of issuance. They must be
considered as works in progress. Please refer to the IETF Web site at http://www.ietf.org
for the latest drafts.
ip extcommunity-list
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Use to create an extended community list for BGP and control access to it.
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A route can belong to any number of communities, so an extended community list can
have many entries comprising many communities.
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You can specify one or more community values when you create an extended
community list. A clause in a route map that includes a list having more than one value
only matches a route having all of the values; that is, the multiple values are logical
ANDed.
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Example
host1(config)# ip extcommunity-list boston1 permit 100:2 100:3 100:4
host1(config)# route-map marengo permit 10
host1(config-route-map)# match extcommunity boston1
95 Copyright © 2010, Juniper Networks, Inc.
Chapter 1: Configuring BGP Routing