Community Lists For Bgp; Extended Community Lists For Bgp; Route Redistribution And Route Maps - Cisco Nexus 7000 Series Configuration Manual

Information About Route Policy Manager
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m .

Community Lists for BGP

You can filter BGP route updates based on the BGP community attribute by using community lists in a
route map. You can match the community attribute based on a community list, and you can set the
community attribute using a route map.
A community list contains one or more community attributes. If you configure more than one community
attribute in the same community list entry, then the BGP route must match all community attributes listed
to be considered a match.
You can also configure multiple community attributes as individual entries in the community list by
using the same community list name. In this case, the router processes the first community attribute that
matches the BGP route, using the permit or deny configuration for that entry.
You can configure community attributes in the community list in one of the following formats:
•
•
•
See the Cisco Nexus 7000 Series NX-OS Unicast Routing Command Reference for more information on
regular expressions.

Extended Community Lists for BGP

Extended community lists support 4-byte AS numbers. You can configure community attributes in the
extended community list in one of the following formats:
•
•
See the Cisco Nexus 7000 Series NX-OS Unicast Routing Command Reference for more information on
regular expressions.
Cisco NX-OS supports generic specific extended community lists, which provide similar functionality
to regular community lists for four-byte AS numbers. You can configure generic specific extended
community lists with the following properties:
•
•

Route Redistribution and Route Maps

You can use route maps to control the redistribution of routes between routing domains. Route maps
match on the attributes of the routes to redistribute only those routes that pass the match criteria. The
route map can also modify the route attributes during this redistribution using the set changes.
The router matches redistributed routes against each route map entry. If there are multiple match
statements, the route must pass all of the match criteria. If a route passes the match criteria defined in a
route map entry, the actions defined in the entry are executed. If the route does not match the criteria,
the router compares the route against subsequent route map entries. Route processing continues until a
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
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A named community attribute, such as internet or no-export.
In aa:nn format, where the first two bytes represent the two-byte AS number and the last two bytes
represent a user-defined network number.
A regular expression.
In aa4:nn format, where the first four bytes represent the four-byte AS number and the last two bytes
represent a a user-defined network number.
A regular expression.
Transitive—BGP propagates the community attributes across autonomous systems.
Nontransitive—BGP removes community attributes before propagating the route to another
autonomous system.
Chapter 16 Configuring Route Policy Manager
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