An optimal and fully explicit rate controller for high-speed networks

We have designed and investigated a new congestion control scheme, called the OFEX (Optimal and Fully EXplicit) controller. Different from the existing relatively explicit controllers, this new scheme is able to provide not only optimal bandwidth allocation but also fully explicit congestion signal to sources. It overcomes the drawback of the relatively explicit controllers that “bias” the multi-bottlenecked users, and improves their convergence speed and source throughput performance. Furthermore, the OFEX controller design considers a dynamic model by proposing a remedial measure against the unpredictable bandwidth changes in contention-based networks (such as shared Ethernet and IEEE 802.11). Compared with the former works/controllers, such a remedy also effectively reduces the instantaneous queue size in a link, and thus significantly improving the queueing delay and system stability performance. We have evaluated the effectiveness of the OFEX controller in OPNET. The experimental comparison verifies the superiority of the OFEX controller.