A More Precise Latency Bound of Deficit Round-Robin Scheduler

Delay is an important Quality of Service (QoS) parameter. A significant part of an end-to-end delay of a data flow is latency – the delay induced by scheduling algorithms in network devices. In this paper we present a latency analysis of a Deficit Round-Robin (DRR) scheduler. We correct inaccuracies and deficiencies of the DRR latency analysis detected in works of other authors. We derive a new and more precise latency bound of the DRR scheduler and show that, contrary to the latency bounds derived by other authors, our bound is mathematically correct. Finally we give a comparative analysis of the DRR latency bounds discussed in the paper.