A control theoretic analysis of RED

TLDR

The study aims to use a nonlinear TCP model to analyze and design RED‑based AQM systems, prioritizing robustness to load variations. The authors linearize the TCP–queue interconnection, analyze its feedback properties, and design a RED‑based AQM controller by mapping filter break point and loss probability to link capacity, load, and round‑trip time. They provide guidelines for achieving linear stability under varying propagation delays and loads, though no simulation results are presented.

Abstract

We use a previously developed nonlinear dynamic model of TCP to analyze and design active queue management (AQM) control systems using random early detection (RED). First, we linearize the interconnection of TCP and a bottlenecked queue and discuss its feedback properties in terms of network parameters such as link capacity, load and round-trip time. Using this model, we next design an AQM control system using the RED scheme by relating its free parameters such as the low-pass filter break point and loss probability profile to the network parameters. We present guidelines for designing linearly stable systems subject to network parameters like propagation delay and load level. Robustness to variations in system loads is a prime objective. We present no simulations to support our analysis.