Ecient F Air Queuing Using Decit round Robin

Fair queuing is a technique that allows each ow passing through a network device to have a fair share of network resources. Previous schemes for fair queuing that achieved nearly perfect fairness were expensive to implement: speci cally, the work required to process a packet in these schemes was O(log(n)), where n is the number of active ows. This is expensive at high speeds. On the other hand, cheaper approximations of fair queuing that have been reported in the literature exhibit unfair behavior. In this paper, we describe a new approximation of fair queuing, that we call De cit Round Robin. Our scheme achieves nearly perfect fairness in terms of throughput, requires only O(1) work to process a packet, and is simple enough to implement in hardware. De cit Round Robin is also applicable to other scheduling problems where servicing cannot be broken up into smaller units, and to distributed queues.