ISO/IEC 9646-2:1994

Overview

ISO/IEC 9646-2:1994 - "Information technology - Open Systems Interconnection - Conformance testing methodology and framework - Part 2: Abstract Test Suite specification" - defines requirements and guidance for producing system‑independent Abstract Test Suites (ATS) for OSI specifications. This second edition cancels and replaces the 1991 edition and is intended for use throughout the OSI conformance testing lifecycle, including draft conformance specifications. The standard focuses on abstract test cases that check conformance by controlling and observing protocol behaviour (Protocol Data Units and Abstract Service Primitives).

Key topics and technical requirements

• Scope and applicability: ATS production for one or more OSI protocols, including adjacent or embedded protocols; excludes tests that cannot be expressed via PDUs/ASPs.
• Conformance clauses: Requirements on base specifications to include clear, decidable static and dynamic conformance clauses and to distinguish mandatory, optional, and prohibited behaviours.
• Test Suite Structure (TSS&TP): Guidance on organizing test suites and specifying Test Purposes to ensure coverage and clarity.
• Abstract Test Methods (ATMs): Definition and selection of single‑party and multi‑party abstract test methods (e.g., distributed, coordinated, remote), plus variants (embedded/non‑embedded, multi‑user).
• Test case specification: Rules for abstract test case composition, subdivision into test steps, and assignment of verdicts.
• Test Management Protocol (TMP): Specification requirements for exchanging control and management information between testers and system under test.
• Notation and tools: Recommends use of standardized test notations - notably TTCN (Tree and Tabular Combined Notation) - and compliance with ISO/IEC 9646‑3 when used.
• Maintenance and consistency: Requirements for ATS maintenance and consistency with the base protocol specification; guidance for protocol specifiers to facilitate testing.

Practical applications and users

Who benefits:

• Standards bodies and protocol specifiers - to create testable conformance clauses and ICS proformas.
• Test suite developers and test houses - to design ATS that are portable and executable across different test systems.
• Conformance assessment laboratories - to produce Executable Test Suites from ATS and report protocol conformance.
• Implementers and vendors - to validate implementations (IUT/SUT) against OSI protocol standards.

Practical uses:

• Developing standardized, implementer‑neutral ATS for interoperability testing.
• Guiding the conversion of abstract tests to executable test suites.
• Establishing repeatable, objective conformance assessment and reporting.

Related standards

• ISO/IEC 9646‑1 (General concepts) and 9646‑3 (TTCN notation)
• ISO/IEC 9646‑6, 9646‑7 (profiles and ICS)
• ASN.1 / BER references (ISO/IEC 8825, ISO 7498)
• Also published as ITU‑T Recommendation X.291

Keywords: ISO/IEC 9646-2:1994, Abstract Test Suite, ATS, conformance testing, OSI, TTCN, Abstract Test Methods, PDU, TMP, test suite structure.