Rule based delay proportion adjustment for differentiated services

Differentiated services (DiffServ) are becoming very popular to be implemented to provide quality of service (QoS) to various Internet applications. Proportional relative-DiffServ is a recently proposed method aiming to guarantee the ratios of service differences between. However, the outcome of such a method is similar to spreading overall load to each class with a fixed ratio and it allows low priority traffic to affect high priority traffic which is unacceptable. In this paper, we introduce a controller using fuzzy rules to reduce the effect of low priority class upon higher priority ones. Our system adjusts bias of each class using the current traffic condition of the class. The simulation shows that dependency of the delay of a high-priority-class, a value that indicates QoS of the traffic, on lower priority classes is significantly reduced by the proposed method