Class-based weighted fair queuing scheduling on quad-priority Delta Networks

Contemporary networks support multiple priorities, aiming to differentiate the quality of service (QoS) levels offered to individual traffic classes. Support for multiple priorities necessitates the introduction of a scheduling algorithm, to select each time the next packet to transmit over the data link. Class-based weighted fair queuing (CBWFQ) scheduling and its variations are widely used as a scheduling technique since it is easy to implement and prevent the low-priority queues from starvation, i.e. receiving no service during periods of high-priority traffic. CBWFQ effectively thus offers low-priority queues, the opportunity to transmit packets even though the high-priority queues are not empty. In this paper, we present the modelling and performance evaluation of a single-buffered, four-priority multistage interconnection network (MIN) operating under the CBWFQ scheduling policy. Performance evaluation is conducted through simulation, and the performance metrics obtained can be used by MIN designers to set the appropriate queue weights according to the expected traffic and the desired QoS levels for each priority class, delivering efficient thus systems.