Overview
ISO/IEC 13242:1997 defines the Route Restriction Class (ANF‑RRC) additional network feature for Private Integrated Services Networks (PISNs). The standard supplies Stage 1 and Stage 2 specifications: Stage 1 describes the feature as seen by entities that generate, receive, and act on a Route Access Class (RAC); Stage 2 defines the functional model and information flows between functional entities. ANF‑RRC allows an RAC value to be associated with a call to indicate entitlement to use particular routing facilities (for example, international or long‑distance links).
Key topics and technical requirements
- Route Access Class (RAC): an integer that represents a call’s entitlement to use certain facilities during routing.
- Facility Restriction Class (FRC): expresses restrictions on access to a facility in terms of RAC values permitted or denied.
- Functional model (Stage 2): identifies functional entities such as RRC‑initiate (FE1) and RRC‑execute (FE2) and their relationships to basic call entities (e.g., Call Control).
- Information flows: definitions include the ra‑RRC flow and relationships to basic call flows (SETUP, SETUP REJECT referenced).
- Procedures: covers provisioning/withdrawal, activation/deactivation/registration/interrogation, invocation/operation and exceptional procedures.
- Interaction with supplementary services: specifies interworking considerations and interactions with services such as Calling/Connected Line Identification (SS‑CLIP/SS‑COLP), Calling Line Restriction (SS‑CLIR), Call Forwarding variants (SS‑CFU, SS‑CFB, SS‑CFNR), Call Transfer (SS‑CT), Do Not Disturb (SS‑DN), and others.
- Conformance: a Stage 3 standard (signalling protocols and equipment behaviour) is required to claim conformance; Stage 3 must support the Stage 1 and Stage 2 aspects relevant to the interface or equipment.
Applications and who uses it
- PISN operators implement ANF‑RRC to control which calls can use specific network facilities (e.g., restrict international or long‑distance routing).
- Telecom equipment vendors and protocol designers use these specifications when developing exchanges, gateways, and signalling stacks for PISNs.
- Network architects and engineers use the functional model and information‑flow definitions to design routing policies and to ensure correct interworking with other supplementary services.
- Standards and compliance teams reference the document to align Stage 3 signalling protocols with the Stage 1/Stage 2 behaviour.
Related standards
- ISO/IEC 11574 (basic services and Call Control functional entities)
- ISO/IEC 11579‑1 (PISN reference configuration)
- CCITT/ITU‑T recommendations referenced in the standard (e.g., I.130, I.112)
ISO/IEC 13242:1997 is essential for managing call routing entitlements and ensuring consistent facility access controls within PISNs.