A Traffic Policing Approach to Assure Acceptable Grade of Service in Packet Networks

In this paper we deal with the problem of assuring acceptable grade of service and at the same time increasing a total network throughput. This is possible by combining two usually separate switch functions: traffic shaping (policing) and packet scheduling. We have selected a simple packet switch structure with single FIFO (first-in-first-out) queue per input port. Input queuing has an advantage over output queuing – it enables simple isolation between different input ports, providing that proper scheduling mechanism is used. We have proposed a SVC (simplified virtual clock) scheduling mechanism. Simulation results have confirmed the viability of BRFQ (bit-round fair queuing), VC (virtual clock) and SVC scheduling mechanisms. When SVC is used, traffic isolation is somewhat loosened but not entirely eliminated. It is also shown that for selected packet switch structure, SVC scheduling mechanism performs best: it requires minimal buffer sizes and it produces smallest (mean and maximum) packet delays.