Requirements for Token Holding Times in Timed-Token Protocols

Minimum requirements for the high-priority token-holding time in a network using timed-token access protocol (such as IEEE 802.4 and FDDI) are derived in order to show that the throughput of synchronous messages is now lower than the amount of traffic generated for that class. This minimal value is essential in order to avoid unbounded queue length for the synchronous class and to achieve high network responsiveness. The results have been obtained for synchronous messages generated according to a generic periodic pattern; however, as no constraint is assumed for the period, the results obtained may be used to approximate nonperiodic generation patterns. It is shown how the theoretical results can be used to tune the network performance