A combined delay and throughput proportional scheduling scheme for differentiated services

The proportional differentiation model is a service differentiation approach for differentiated services networks that includes several desirable features such as controllability and predictability. This paper proposes and evaluates a scheduling mechanism for the combined control of delay and throughput metrics, within the context of the proportional differentiation model. The scheme is based on the well known Little's Law, and always exercises average delay differentiation, while it implements throughput differentiation only during overload periods, and if certain conditions as satisfied. A moving window averaging mechanism and an active queue management scheme are simultaneously, and, respectively, used to achieve control over the relative throughput values as well as the relative delay values between classes. The scheme does away with measurement of the actual packet delays, and state information is minimized. Some feasibility bounds are presented under the assumption of Poisson arrivals, and a simulation study shows the effectiveness of this scheme.