Configuring a Community Filter

The community attribute identifies routes with the same characteristics without considering IP prefixes and AS numbers. Configuring community filters and community attributes simplifies route management when it is inconvenient to use the IP prefix list or AS_Path filter. For example, a company branch needs to receive routes only from its headquarters and from branches in adjacent countries. In this case, you can configure different community attributes for each of the branches. Routes in the original branch can then be managed based on community attributes, without considering IP prefixes and AS numbers of routes in different countries.

Community filters are classified into standard and expanded community filters. An expanded community filter supports regular expressions (BGP Regular Expressions) and is more flexible than a standard community filter.

• To configure a standard community filter, run the following command:

set routing community-list standard <community-list-name> {deny|permit} [local-as|no-advertise|no-export|internet|community <community>]

• To configure an expanded community filter, run the following command:

set routing community-list expanded <community-list-name> {deny|permit} regex <regular-expression>

The following example configures a standard community list filter:

admin@Xorplus# set routing community-list standard COMMUNITY1 permit community 100:100
admin@Xorplus# commit