Traffic scheduling for QOS guarantees in broadband packet-switched networks

Abstract

Recently, real-time services over the Internet are becoming increasingly popular. A large number of real-time services will have made their way into homes and offices. Since real-time services need far more stringent QoS requirements than the typical sort of data applications, they should be guaranteed minimum bandwidth, jitter, and low end-to-end delays to each flow, regardless of the behavior of other flows. At the same time, data rates continue to increase past OC-12 or gigabit rates to OC-48 towards 10-gigabit Ethernet and the number of users is growing exponentially. All these factors make If QoS with the evolution of the Internet a challenging task. Until now, many mechanisms have presented in order to support QoS guarantees at the network-level. These mechanisms include queuing, traffic scheduling, policing, shaping, and buffer management. It is interesting to observe, however, that the traffic scheduling of all mechanisms is the most critical function in achieving QoS guarantees. This dissertation is on the design, analysis, and implementation framework of traffic scheduling. We first propose a new input arbitration mechanism to reduce synchronization effect of conventional input arbitration. This mechanism is based on a buffered crossbar switch with VOQ at the input. In the proposed method, the starting points of input modules are different from each other in any case. We evaluate the probability that input modules select cells destined for the same output. From the evaluated probability, we identify that the probability is maximized when the input starting points are same. Therefore, we show that the uniqueness of the starting points improves the switch performance. We also confirm the proposed method is better than the conventional methods under the uniform and on-off traffic by simulation. Next, we propose an efficient and simple fair queuing algorithm, called new starting potential fair queuing (NSPFQ). Several algorithms using system virtual...