This International Standard specifies the Route Restriction Class additional network feature (ANF-RRC), which is applicable to various basic services supported by Private Integrated Services Networks (PISN). Basic services are specified in ISO/IEC 11574. ANF-RRC permits a Route Access Class (RAC) to be associated with a call to indicate its entitlement to use certain facilities during routeing. Additional network feature specifications are produced in three stages, according to the method described in CCITT Recommendation 1.130 for supplementary services. This International Standard contains the stage 1 and stage 2 specifications of ANF-RRC. The stage 1 specification (clause 6) specifies the feature as seen by an entity which generates, receives, and acts on the RAC. The stage 2 specification (clause 7) identifies the functional entities involved in the feature and the information flows between them.