ISO/IEC 13874:2003 PDF

Overview

ISO/IEC 13874:2003 - "Information technology - Private Integrated Services Network - Inter‑exchange signalling protocol - Path Replacement additional network feature" - defines the Q‑reference‑point signalling protocol to support the Path Replacement additional network feature (ANF‑PR) in QSIG-enabled Private Integrated Services Networks (PISNs). ANF‑PR lets an established call’s connection between Private Integrated services Network eXchanges (PINXs) be replaced by a newly established connection (optionally retaining part of the old path). This document provides the stage‑3 protocol specification and complements service definitions in ISO/IEC 13863.

Key topics and technical requirements

• Scope and applicability: Protocol applies at the Q reference point between PINXs in a PISN and is intended for PINXs that interconnect to form a PISN.
• Protocol layering: ANF‑PR signalling operates on top of basic circuit‑switched call control (ISO/IEC 11572) and reuses generic supplementary‑service procedures (ISO/IEC 11582).
• Roles & states: Defines operational roles (Requesting, Cooperating, Inviting, Transit, Branching, End PINX) and state machines for each role during ANF‑PR procedures.
• Procedures and coding: Message operations, information elements, ASN.1 coding and message sequences for establishing a replacement path; optional procedures to retain parts of the old connection.
• Interactions: Protocol interactions with supplementary services such as Calling/Connected Name Presentation, Call Transfer (SS‑CT), Completion of Calls to Busy/No Reply (SS‑CCBS/SS‑CCNR), Call Forwarding variants, Call Deflection and others.
• Conformance & testing: Protocol Implementation Conformance Statement (PICS) proforma in Annex A, ASN.1 definitions, SDL representations, and example message flows for implementation and test.
• Timers and parameters: Specification includes protocol timers (T1–T4) and operational requirements for reliable switchover.

Applications and who uses it

ISO/IEC 13874:2003 is relevant for:

• PBX/PINX manufacturers implementing QSIG inter‑exchange signalling and ANF‑PR support.
• Telecommunications vendors and system integrators deploying enterprise PISNs requiring call path replacement (e.g., maintenance, rerouting, resilience).
• Network architects and operators designing call continuity and advanced call control behaviors across multi‑vendor private networks.
• Test labs and compliance engineers using the PICS, ASN.1 and SDL artifacts for conformance testing and interoperability verification.

Practical uses include in‑call path migration, network maintenance without dropping active calls, and implementing policy‑driven reconnection logic across corporate telephony networks.

Related standards

• ISO/IEC 13863 (ANF‑PR service specification stages 1–2)
• ISO/IEC 11572 (basic circuit‑switched call control)
• ISO/IEC 11582 (generic supplementary services)
• ISO/IEC 11579‑1 (PISN reference configuration)
• ETS 300 387 (service specification method)

Keywords: ISO/IEC 13874:2003, ANF‑PR, Path Replacement, QSIG, PINX, PISN, inter‑exchange signalling protocol, private network call migration.