Emulated weighted fair queueing algorithm for high-speed packet-switched networks

In this paper we propose an efficient and simple fair queueing algorithm, called emulated weighted fair queueing (EWFQ), which has O(1) complexity for the virtual time computation while it almost perfectly emulates the delay and fairness properties of WFQ (weighted fair queueing). The key idea of EWFQ is that it calibrates the system virtual time only at the end of each packet transmission, while it updates the system virtual time for a newly arrived packet by adding elapsed real time between two calibration events to the recent system virtual time. By doing so, EWFQ has a rate-proportional property. If any fair queueing algorithm can be categorized into the rate proportional class and input is constrained by a leaky bucket, its delay is bounded and the same as that of WFQ. EWFQ can, therefore, almost perfectly emulate the delay and fairness performances of WFQ while the implementation complexity is drastically reduced to O(1). EWFQ can be implemented in a router for supporting the differential and integrated service.