ISO/IEC/IEEE International Standard - Information technology - Local and metropolitan area networks - Part 5: Token ring access method and physical layer specifications

This Local and Metropolitan Area Network standard, ISO/IEC 8802-5 :1992, is part of a family of local area network (LAN) standards dealing with the physical and data link layers as defined by the ISO Open System Interconnection Reference Model. Its purpose is to provide compatible interconnection of data processing equipment by means of a local area network using the token-passing ring access method. The frame format, including delimiters, addressing, and frame-check sequence, are defined, and medium access control (MAC) frames, timers, and priority stacks are defined. The MAC protocol is defined. The finite-state machine and state tables are supplemented with a prose description of the algorithms. The physical layer (PHY) functions of symbol encoding and decoding, symbol time, and latency buffering are defined. The services provided by the MAC to the station management (SMT) and the services provided by the PHY to SMT and the MAC are described. These services are defined in terms of service primitives and associated parameters. The 4 and 16 Mb/s, shielded twisted pair attachment of the station to the medium, including the medium interface connector (MIC) are also defined. The applications environment for the LAN is intended to be commercial and light industrial. The use of token ring LANs in home and heavy industrial environments, while not precluded, has not been considered in the development of the standard. A Protocol Implementation Conformance Statement (PICS) proforma is provided as an annex to the standard.