Priority Strategy For Computer Network Modeling Study

Modern computer communication network is heading for ATM switching networks and B-ISDN, which integrated various traffics such as voice, data, fax and video. Each type of traffic has different traffic characteristic and requires different quality of service (QoS) requirements. Thus, a proper priority control is needed in order to utilize the network resources efficiently and satisfy the QoS of each traffic. However, the priority control strategy in primary protocol only adapts to the state with few ranks. It needs to be improved to adapt to ATM and B-ISDN. In this paper, an improved strategy in IEEE802.5 Token Ring protocol, that is, "high priority rank interrupt strategy" is proposed which can prevent the low ranks information (especially the lowest rank information) waiting for a long time. We also analyze a practicable ATM priority scheme with two kinds of traffic. The scheme is studied by setting up mathematic model with traffic theory. We obtain several important parameters such as the probability distribution of the queue length and the average waiting time of cell by numerical methods. The theory innovation in this paper not only can instruct the design and construction of ATM networking and B-ISDN, but also lay a foundation for future innovation research in this field.