Design and analysis of a fair scheduling algorithm for QoS guarantees in high-speed packet-switched networks

B-ISDNs are required to support a variety of services such as audio, data, and video, so that the guarantee of Quality-of-Service (QoS) has become an increasingly important problem. An effective fair scheduling algorithm permits high-speed switches to divide link bandwidth fairly among competing connections. Together with the connection admission control, it can guarantee the QoS of connections. In this paper, we propose a novel fair scheduling algorithm, called "Virtual-Time-based Round Robin(VTRR)." Our scheme maps the priorities of packets into classes and provides service to the first nonempty class in each round. And it uses an estimation method of the virtual time necessary to this service discipline. To find the first nonempty class, VTRR adopts a priority queueing system of O(log log c) which decreases the number of instructions which need to be carried out in one packet transmission time segment. These policies help VTRR implementation in software, which presents flexibility for upgrades. Our analysis has demonstrated that VTRR provides bounded unfairness and its performance is close to that of Weighted Fair Queuing. Therefore, VTRR has a good performance as well as simplicity, so that it is suitable for high-speed B-ISDN.