By Rong Pan, Preethi Natarajan, Chiara Piglione, Mythili S. Prabhu, Alon Bernstein, Advanced Architecture & Research Group, Cisco Systems Inc.
Abstract—Bufferbloat is a phenomenon where excess buffers in the network, such as in cable modems or wireless APs, cause high latency and jitter. As more and more interactive applications (e.g. voice over IP and real time video conferencing) run in the Internet, high latency and jitter degrade application performance and impact users’Quality of Experience (QoE). There is a pressing need to design intelligent queue management schemes that can control latency and jitter; and hence provide desirable quality of service to users.
We present here a lightweight design, PIE (Proportional Integral controller Enhanced), that can effectively control the average queueing latency to a reference value. The design does not require per-packet extra processing, so it incurs very small overhead and is simple to implement in both hardware and software. In addition, the design parameters are self-tuning, and hence PIE is robust and optimized for various network scenarios. We apply thealgorithm in DOCSIS 3.0 environment. Simulation results show that PIE can ensure low latency and achieve high link utilization under various congestion situations.
Index Terms—bufferbloat, Active Queue Management(AQM), Quality of Service (QoS), Quality of Experience(QoE), Explicit Congestion Notification (ECN)