ISO/IEC 7498-3:1997

Overview

ISO/IEC 7498-3:1997 - "Information technology - Open Systems Interconnection - Basic Reference Model: Naming and addressing" is an architectural standard that defines how names and addresses are used to identify and locate objects within the OSI (Open Systems Interconnection) environment. It is an ISO/IEC standard identical to ITU‑T Recommendation X.650 (second edition, 1997). The document provides principles and mechanisms for naming and addressing across layered OSI services while preserving layer independence and implementation independence. It is expressly an architectural guide, not an implementation specification or conformance test.

Key Topics

• Architectural principles for naming and addressing within the OSI reference model, including flexibility for future evolution.
• Definitions of core concepts such as (N)-address, (N)-selector, (N)-entity, (N)-directory-function, and association among peer entities.
• Address parameters used in OSI service primitives: calling-(N)-address, called-(N)-address, responding-(N)-address.
• OSI addressing model: how addresses relate to service access points (SAPS), sublayers, and peer associations.
• Addressing information in protocols: mapping of addressing data into (N)-PDU components and network-layer interactions.
• Addressing across OSI layers: specific guidance for Application, Presentation, Session, Transport, Network, Data Link, and Physical layers.
• Naming domains, authorities, and registration procedures for managing names and ensuring unambiguity within scopes.
• Directory facility requirements and (N)-directory-functions for mapping between names, addresses, and other identifiers.

Applications

ISO/IEC 7498-3 is used to:

• Guide standards developers and working groups when defining naming/addressing schemes for OSI-related protocols.
• Assist network architects and protocol designers in modeling address spaces, service access points, and peer associations.
• Inform system integrators and implementers about the architectural expectations for name/address handling across layers.
• Support directory and registry administrators in designing directory facilities and registration procedures for naming domains.

Because the standard focuses on architecture and mappings rather than byte-level encodings, it is valuable wherever consistent, interoperable naming and addressing models are needed without constraining internal system design.

Related Standards

• ISO/IEC 7498-1 / ITU‑T X.200 - Basic Reference Model (OSI)
• ISO/IEC 7498-2 - Security Architecture
• ISO/IEC 7498-4 - Management Framework
• ITU‑T X.650 - identical text to ISO/IEC 7498-3
• Other referenced ITU‑T Recommendations and ISO/IEC standards on OSI services and protocols

Keywords: ISO/IEC 7498-3, OSI naming and addressing, Open Systems Interconnection, (N)-address, directory facility, naming domains, calling address, called address, OSI addressing model.