A token ring protocol for integrated services.

Abstract

In this thesis we present a new token-ring protocol, called the rotation counter protocol (RCP), for integrated services. The main feature of this protocol is that the token contains a special field called the rotation counter. This counter can be examined by every station and is used to count down the number of packets transmitted in one cycle. In each cycle, voice packets are collected first, and data packets could be transmitted only if the counter value is non-zero. In this way, voice packets are given a higher priority to access the network so that their real-time requirement can be satisfied. Two variations of the protocol, RCP-I and RCP-II, are presented. They have different delay performances. In RCP-I, the mean voice packet access delay is dependent on the offered data load, while in RCP-II, such delay can be made almost independent with a small delay jitters. The almost constant mean delay and small delay jitters can thus better serve synchronous traffic. Algorithms for the two protocols are given. They are easy to implement. The RCP performances are evaluated under various network conditions to demonstrate their desirable features. The comparison among the RCP-I, RCP-II, and FDDI is executed. The procedures on fault recovery and how to choose parameters are discussed as well.