To configure VPI/VCI closed user groups, you must bind VPI/VCIs to a given service as described below. Closed user groups allow all users accessing the NRP-SSG through the VPI/VCI or range of VPI/VCIs to access the service. You can specify whether users are allowed to access only the bound service or other additional services to which they subscribe. A closed user group service can only be selected through the VPI/VCI and not by entering the domain name in the user name of a PPP session.