EVALUATION OF TRANSMISSION CONTROL METHOD IN A SLOTTED RING NETWORK

In this paper, an analysis of a slotted ring type network, the Pierce type ring network, is carried out and characteristics of the ring are derived. The ring type network is one of the fundamental computer netw ork topologies. It is easy to implement and has many merits such as lo w cost and expansion flexibility. However, possible hogging, or domina tion of slots by one station, is one of its drawbacks. At first, when we regard vacant slots as usable, we show how system performance is fa irly dependent on traffic patterns. We also show quantitatively that w hen slots are fixed to each station, domination of the ring can be com pletely prevented, although the performance of the system will be redu ced. We propose a method to control the transmission of packets in whi ch we have positively adopted the insertion of shift registers into th e transmission line to prevent the deterioration of the performance. W ith the insertion of shift registers, we show the feasibility of impro ving the performance of the fixed slot allocation method at the same t ime as preventing domination of the ring. We will discuss the merits o f the shift register insertion:method, which is introduced to improve the fixed slot and semi-fixed slot allocation methods. In the slotted ring type system, four types of slot allocation method including a reg ister insertion method are considered for the improvement of the syste m performance. The merits and demerits of the methods are discussed. W e show how system performance depends on the traffic patterns consider ed. We analyse the characteristics of the ring system under various co nditions.