ISO/IEC 9805-1:1998

Overview

ISO/IEC 9805-1:1998 specifies the protocol for the Commitment, Concurrency and Recovery (CCR) service element in the Open Systems Interconnection (OSI) architecture. This third-edition international standard describes CCR Protocol Version 2, including message (APDU) definitions, procedural elements, and a protocol state machine. The standard is intended to be applied by reference from other specifications (for example via ITU‑T Rec. X.851 / ISO/IEC 9804) and is applicable to a wide range of application-process communication requirements.

Key topics and technical requirements

• Protocol elements: CCR APDUs are defined using Abstract Syntax Notation One (ASN.1). The specification covers the structure and datatype definitions (Annex A) needed to build CCR messages.
• Procedures and state machine: Detailed elements of procedure (initialization, begin branch, prepare, commit, rollback, cancel, recovery, etc.) and a CCR protocol machine expressed as a state table are provided.
• Functional units supported: static commitment, dynamic commitment, read-only, one-phase commitment, cancel, and overlapped recovery.
• Reference mapping: Clause 9 defines a reference mapping that uses the ACSE, Presentation, and Session services to carry CCR semantics. Annex B describes alternative mappings for use with other ASEs when the reference mapping conflicts.
• Session Data Separation: Version 2 uses the Session Data Separation functional unit to protect data not belonging to the CCR atomic action.
• Conformance: Static and dynamic conformance requirements are specified; the standard defines what implementations must support but does not contain test suites.

Practical applications and users

Who uses ISO/IEC 9805-1:

• System architects and protocol engineers designing distributed transaction and recovery mechanisms over OSI stacks.
• Vendors of middleware, application servers, and transaction processing systems that implement CCR semantics across networks.
• Standards authors who reference CCR services (via ISO/IEC 9804 / ITU‑T X.851) to invoke consistent commitment, concurrency, and recovery behavior.

Typical applications:

• Distributed transaction coordination in heterogeneous environments.
• Recovery and rollback mechanisms for multi-party application interactions.
• Ensuring atomic action delimitation and concurrency control across OSI associations.

Related standards

• ITU‑T Rec. X.851 / ISO/IEC 9804 (CCR service definitions)
• ASN.1 specification references (ITU‑T Rec. X.680 / ISO/IEC 8824‑1)
• Presentation service references (ITU‑T Rec. X.216 / ISO/IEC 8822)
• OSI Reference Model (ISO/IEC 7498‑1)

ISO/IEC 9805-1 is primarily a protocol-level specification for implementers and integrators who need robust, standards-based commitment, concurrency and recovery services in OSI-based distributed systems.