A Practical Scheduler For High-Speed Packet Switches and Internet Routers

The input queued (IQ) crossbar based switching, employing virtual output queueing (VOQ), is the dominant architecture for high-performance packet switches. The performance of a VOQ switch depends solely on the scheduling algorithm used. Maximum Weight Matching (MWM) algorithms have optimal performance however they are not practical due to their hardware complexity. Round Robin (RR) based algorithms, on the other hand, are practical but lack performance. The goal of this paper is to propose a scheduling algorithm that has the performance of the MWM based algorithms and the cost and reduced complexity of the RR based algorithms. We show that, by combining the Static Round Robin (SRR) technique with a pre-Matching (pM) phase, we increase the performance. In order to mimic the performance of the MWM algorithms, we give priority to newly arriving traffic. In particular, we propose a new SRR-pM based scheduling algorithm named SMART (Srr-pM current ARrival firsT). Our proposed algorithm achieves high-performance under a wide range of realistic traffic patterns. Furthermore, SMART requires no extra hardware complexity compared to state-of-the art RR algorithms while achieving higher performance. Keywords— Switching, Scheduling, VOQ, Static RoundRobin, Performance, Hardware requirement.