PIE: A lightweight control scheme to address the bufferbloat problem

TLDR

Bufferbloat, caused by oversized buffers, induces high latency and jitter that degrade performance of interactive applications such as VoIP, video conferencing, and financial transactions. The authors propose PIE, a lightweight Proportional Integral controller Enhanced scheme, to maintain average queueing latency at a desired reference level. PIE achieves this without per‑packet extra processing, incurs minimal overhead, is easy to implement in hardware or software, and its self‑tuning parameters make it robust across network conditions. Simulations, theoretical analysis, and Linux testbed experiments demonstrate that PIE delivers low latency while sustaining high link utilization under diverse congestion scenarios.

Abstract

Bufferbloat is a phenomenon where excess buffers in the network cause high latency and jitter. As more and more interactive applications (e.g. voice over IP, real time video conferencing and financial transactions) run in the Internet, high latency and jitter degrade application performance. 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. Simulation results, theoretical analysis and Linux testbed results show that PIE can ensure low latency and achieve high link utilization under various congestion situations.