A combined token/random access protocol for high-speed LAN/MAN ring networks

A distributed token access protocol for servicing synchronous and asynchronous traffic on a ring network is described. A random access mode is superimposed to enhance network efficiency by utilising the slack capacity not attainable by the basic distributed token access mode. The resultant combined token/random access (CTRA) protocol handles synchronous and asynchronous transmissions on a pure packet-switching basis. A salient feature of the add-on random access mode is the provision of concurrent transmission by the participating stations whenever the opportunity presents itself. Numerical results demonstrate the effectiveness of the CTRA protocol