A fair integrated voice/data protocol for token ring networks

The real-time constraint of voice traffic is well satisfied under the proposed protocol. The limit of the allowed number of simultaneous active voice calls is also derived. For the data traffic, since the load of each data station may be quite different, a p-persistent protocol is adopted to ensure fair data packet delay; that is, each data station i can transmit its data packets with probability Pi when it captures the free token. In general, the data stations with higher packet arrival rates will have higher transmission opportunities. Based on a Markov chain model, the appropriate value of Pi for station i in the data subcycle can be obtained. Comparisons are made between this p-persistent protocol and the round-robin scheme by simulation. It is found that the variance of the packet delay under the p-persistent protocol is better than that under the round-robin scheme. Although the p-persistent protocol introduced longer packet delay, the difference is small