Cell transfer quality control in an ATM network

Asynchronous transfer mode (ATM) networks will provide multimedia services with diversified traffic flow characteristics and quality requirements (e.g., cell loss rate and queuing delay). In such a multimedia environment, the bandwidth efficiency can be improved by defining multiple quality of service (QOS) classes and using a traffic control which manages required QOS of each class individually (QOS control). In this paper, by evaluating cell transfer capacity with multiple priority queues, the effectiveness of the QOS control will be discussed. In order to quantitatively evaluate the control performance, the region determined by the offered load of each class where the QOS requirements of all the classes are satisfied (admissible offered load region) is analytically obtained and various combinations of two classes and related control effects is discussed. The results illustrate that when required values of cell loss rate and delay time are both different between the classes, the control effect is large; however, when only either of them is different, the effect is relatively small. This control method is more effective when the inter-class quality difference is bigger and the burstiness of the traffic is stronger. [In Japanese.]