Priority assignment control of ATM line buffers with multiple QOS classes

In an asynchronous transfer mode (ATM) network 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). Priority assignment control is presented as a QOS control method in an ATM switching node. 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 is analytically obtained and various combinations of two classes and related control effects are discussed. 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. The control scheme to enlarge the actual admissible offer load region by adaptively changing the priority assignment ratio is presented and its feasibility is confirmed by the simulation