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Journal of Inforamtion Science and Engineering, Vol.7 No.1, pp.81-100 (March 1991)
An Integrated Voice/Data Protocol for
Token Ring Networks with Fair Accesses*

Wen-Tsuen Chen, Rong-Ruey Lee, Jiunn-Hwa Yu and Ching-Ho Huang
Department of Computer Science
National Tsing Hua University
Monterey, CA. 93943

In this paper, we propose a fair integrated voice/data protocol for token ring networks. The real-time constraint of voice traffic is well satisfied under this 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 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 our p-persistent protocol and the round-robin scheme by simulation. We find that the variance of the packet delay under our protocol is better than that under the round-robin scheme. Although the p-persistent protocol introduces a longer packet delay, the difference is small.

Keywords: token ring networks, markov chain model, p-persistent protocol, Poisson process, round-robin scheme, integrated voice/data

Received April 13, 1990; revised September 24, 1990.
Communicated by J. F. Chang.
*A preliminary version has been presented in the IEEE GLOBECM'90.
This work was supported by Taiwan International Standard Electronics Ltd. And the National Science Council of the Republic of China under Grant NSC77-0404-E007-18 and NSC78-0404-E007-16.