Design of a Stabilizing Second-Order Congestion Controller for Large-Delay Networks

This paper addresses the problem of the stability of congestion control for networks with large round-trip communication delays. Nearly all the existed AQM schemes neglect the impact on system behavior, such as stability, robustness and convergence, caused by large communication delay. The drastic queue oscillations in large delay networks of PI, REM and DC-AQM decrease the link utilization and introduce the avoidable delay jitter. To address this problem, we develop a robust IMC-PID congestion controller based on internal model control principle to restrict the negative impact on the stability caused by the large delay. Simulation results demonstrate that the integrated performance of proposed scheme outperforms others as communication delay increases, and achieves high link utilization and small delay jitter.