IEEE 802.4 defines the media access control (MAC) layer for bus networks that use a token-passing mechanism (token bus networks). This is an application of the concepts used in token ring networks. The main difference is that the endpoints of the bus do not meet to form a physical ring. The IEEE 802.4 Working Group is disbanded. media access control is where people try to access a control to the media. ... A bus network is a network architecture in which a set of clients are connected via a shared communications line, called a bus. ... Token bus is token ring over a virtual ring on a coaxial cable. ... Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ...