Quality of service aware adaptive target queue length generation for active queue management

Active queue management techniques have been proposed to mitigate serious congestion issues caused by transmission control protocol flows. Active queue management controllers based on control theory are superior in terms of control performance. Such a controller utilizes a target queue length as a control input, and the congestion control system attempts to maintain the actual queue length close to the target value. However, the specific setting of the target queue length has not been discussed sufficiently. For example, raising or lowering the target queue length may increase goodput or reduce queueing delay, respectively. Therefore, the target queue length should be appropriately generated according to the required quality of services and buffer status. This paper proposes a quality of services–aware adaptive target queue length generation algorithm for an active queue management controller based on control theory. The proposed algorithm comprises two modes (loss-aware and delay-aware modes) and attempts to raise or lower the target queue length by considering the buffer status to increase the goodput or reduce the queueing delay. Simulation results revealed that the proposed algorithm could increase goodput or reduce queueing delay on each mode by adapting to the buffer status, which is in contrast to conventional methods.