Performance evaluation of new fair queuing algorithm based on CSFQ architecture

A new algorithm called core-stateless random-early-detection (CS-RED) is described. This algorithm can improve the fairness characteristics under a wide range of network conditions and is robust in terms of the setting of its control parameters. It can be used in a distributed architecture, as can the core-stateless fair-queuing (CSFQ) algorithm, so it is applicable to large-capacity backbone routers. Through a detailed evaluation, this paper identifies and clarifies the fairness degradation problem in the CSFQ algorithm. CS-RED was derived to solve this problem by incorporating congestion notification in the RED algorithm. Evaluation of the CS-RED algorithm by computer simulation and comparison of the fairness characteristics in networks using either the CS-RED or the CSFQ algorithm showed that a higher level of fairness is achieved with the CS-RED algorithm under a wide variety of network conditions without degrading link utilization. The treatment necessary to prevent unresponsive flows in best effort networks is also discussed. We have found that a more general treatment, rather than the penalty box, can be used with the CS-RED algorithm.