Overview
ISO/IEC 13246:1997 - "Information technology - Telecommunications and information exchange between systems - Broadband Private Integrated Services Network - Inter-exchange signalling protocol - Signalling ATM adaptation layer" - defines the B‑QSIG SAAL (Signalling ATM Adaptation Layer) used at the Q reference point between Broadband PINXs and between Broadband PISNs. The standard specifies how the SAAL uses ATM layer services to provide reliable transport and service primitives required by B‑QSIG Layer‑3 signalling protocols in a B‑ISDN/ATM environment.
Key topics and technical requirements
- SAAL structure: Three sublayers are defined - Common Part (AAL Type 5), SSCOP (Service Specific Connection Oriented Protocol), and SSCF (Service Specific Coordination Function) for B‑QSIG.
- AAL Type 5: Provides transparent transfer, 32‑bit CRC checking, segmentation into ATM cells and reassembly for SSCOP SDUs.
- SSCOP: Handles connection establishment/release and reliable in‑order exchange of signalling information between peer B‑PINX entities.
- SSCF for B‑QSIG: Maps Layer‑3 signalling requirements to SSCOP services and provides assured transfer and transparency of SDUs (default octet‑aligned up to 4096 octets). Only point‑to‑point B‑QSIG SAAL connections are supported.
- Operational modes: Two peer‑to‑peer modes - Assured Operation (mandatory) and Unassured Operation (optional; not required by B‑QSIG Layer‑3).
- Connection model: Connection‑oriented; SAAL connections are established as part of an Inter‑PINX Link (IPL) and normally remain permanent except to recover from errors.
- Traffic management: Peer entities must be preconfigured with traffic parameters (examples: peak cell rate e.g. 167 cells/s; or PCR/SCR/MBS or UBR). Configuration method is out of scope but must match on both ends.
- Conformance: Annex A provides a PICS (Protocol Implementation Conformance Statement) proforma for implementers and testers.
Practical applications and users
This standard is intended for:
- Telecom equipment vendors implementing Broadband PINX/PISN signalling stacks and SAAL layers.
- Protocol and firmware developers building B‑QSIG Layer‑3 interexchange signalling over ATM.
- Network integrators and carriers operating B‑ISDN/ATM-based private networks requiring interoperability between PINXs.
- Test labs and QA engineers using the PICS proforma to validate conformance and interworking.
ISO/IEC 13246:1997 is essential when you need standardized, reliable ATM‑based signalling transport between private exchanges (B‑PINX/B‑PISN), particularly in environments using B‑ISDN, ATM, and B‑QSIG signalling.
Related standards
- ITU‑T Rec. I.363.5 (AAL Type 5), Q.2110 (SSCOP), Q.2130 (SSCF), Q.2100 (SAAL overview)
- ISO/IEC 9646‑1 and 9646‑7 (conformance testing and PICS guidance)