Overview
6-10 Configuring the Border Gateway Protocol
learn, advertise, or redistribute routes. When routes are aggregated, the resulting aggregate has a
COMMUNITIES attribute that contains all communities from all the initial routes.
Community lists form groups of communities for use in a route map’s match clause. Similar to
ACLs, you can create a series of community lists where statements are checked until a match is
found and when one statement is satisfied, the test is finished with the ip community-list
community-list-number {permit | deny} community-number command.
To configure the COMMUNITIES attribute and match clauses based on communities, refer to the
match community-list and set community command descriptions in “BGP Community with
Route Maps Examples” on page 6-26 and the XSR CLI Reference Guide.
Although a COMMUNITIES attribute is not sent to a neighbor by default, you can specify the
attribute be sent to the neighbor at an IP address with the neighbor {ip-address | peer-
group-name} send-community command.
Figure 6-7 Application of Community Attribute