Overview
ISO 21806-3:2020 specifies the conformance test plan (CTP) for the application layer of Media Oriented Systems Transport (MOST), a synchronous time-division-multiplexing (TDM) network used in automotive multimedia and infotainment systems. The document defines how to structure and execute conformance test cases (CTCs) that verify an implementation of the MOST application layer (as specified in ISO 21806-2) meets the standard’s functional and behavioural requirements. Interoperability testing is explicitly out of scope.
Key technical topics and requirements
ISO 21806-3 organizes and details conformance test cases across core application-layer areas:
- Device model - tests verifying the MOST function block (FBlock) model and device behaviour.
- Data and basic data types - validation of supported types and data handling at the application layer.
- Registry management - conformance of central registry operations (NetworkMaster/NetworkSlave) and registry-related CTCs (including InstID wildcard behaviour).
- Connection management - tests for establishing, maintaining and releasing application-layer connections and streaming resources.
- Error management - test cases for restart behaviour, reaction to network change events and other error scenarios.
- Diagnosis - tests and procedures for diagnostic information and testability (e.g., EnhancedTestability FBlock).
Additional structural topics in the standard include test set-up, CTP organisation, timer and deadlock conventions, multi-node device handling, required procedures, and an annex on measurement uncertainty for individual CTCs.
Practical applications and benefits
- Provides a repeatable, standardised framework for conformance testing of MOST application-layer implementations used in automotive infotainment and multimedia devices.
- Enables test tool and test lab development by defining explicit conformance test cases (CTCs) and procedures.
- Helps OEMs and suppliers validate that devices implement MOST FBlocks, registry, connection and error handling correctly - reducing integration risk and time-to-market.
- Supports quality assurance for devices acting as sink/source nodes, power management roles (PowerMaster/PowerSlave), and network master/slave registry roles.
Who should use this standard
- Automotive OEMs and system integrators specifying MOST compliance requirements.
- Component and device suppliers developing MOST-enabled infotainment hardware and software.
- Independent test laboratories and tool vendors implementing conformance test suites.
- Certification bodies and quality teams responsible for compliance verification.
Related standards
Keywords: ISO 21806-3, MOST conformance test plan, Media Oriented Systems Transport, application layer testing, automotive infotainment, FBlock, registry management, conformance test cases.