The Research On Priority Control In ATM Network

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). 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, in order to find a more proper priority control strategy which can be used in integrated services, an improved strategy in IEEE802.4 Token bus protocol is proposed which can prevent the low ranks information waiting for a long time.Based on the research of priority strategy on local area network and wide area network, in this thesis, we put forward an extended Kendall model for the priority scheduling input - line group output with multi-channel in ATM exchange system'L1: The size of buffer l / FCFS (for same kinds of cells)' L2: The size of buffer2/ Non-typical Non-Prevail PR (for different kinds of cells) and then use the average method to model and analyze mathematically the non-typical and non-anticipative PR model. This research is firstly studied in this paper. Compared with the typical and non-anticipative PR model, it expresses more exactly the characteristics of the priority scheduling input - line group output with multi-channel in ATM exchange system. The final simulation experiment shows that this model can better the HOL block, and improve the performance of input-queued ATM switch dramatically.