IEEE 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 afamily of local area network (LAN) standards dealing with the physical and data link layers asdefined by the ISO Open System Interconnection Reference Model. Its purpose is to providecompatible interconnection of data processing equipment by means of a local area network usingthe token-passing ring access method. The frame format, including delimiters, addressing, andframe-check sequence, are defined, and medium access control (MAC) frames, timers, andpriority stacks are defined. The MAC protocol is defined. The finite-state machine and statetables 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. Theservices provided by the MAC to the station management (SMT) and the services provided by thePHY to SMT and the MAC are described. These services are defined in terms of serviceprimitives and associated parameters. The 4 and 16 Mb/s, shielded twisted pair attachment ofthestation to the medium, including the medium interface connector (MIC) are also defined. Theapplications environment for the LAN is intended to be commercial and light industrial. The useof token ring LANs in home and heavy industrial environments, while not precluded, has notbeen considered in the development of the standard. A Protocol Implementation ConformanceStatement (PICS) proforma is provided as an annex to the standard.