Analysis of asymmetric prioritized token ring

An asymmetric prioritized token-ring operation with nonpreemptive priority queuing and a limited service discipline at each station is discussed. The number of message priority levels and the walktime vary from one station to another. Moreover, the assumed Poisson message arrival process and the message transmission time vary not only from one station to another but also from one class to another. The analysis focuses on the observation that upon the arrival of a tagged message at a station, the server is either performing walktime, serving a message at the station at which the tagged message arrived, or else serving a message at another station. On the basis of these mutually exclusive cases, three special period intervals required to carry the analysis through are defined. The analysis of the main message delay is based on characteristics of the cycle time as well as on these special period intervals, and in all cases the balance of flow is of particular interest. The performance as measured by the expected delay for any message class at any station is derived, and the numerical results are validated through simulation. >