A Control-Theoretic and Online Learning Approach to Self-Tuning Queue Management

There is a growing trend that network applications not only require higher throughput, but also impose stricter delay requirements. The current Internet congestion control, which is driven by active queue management (AQM) algorithms interacting with the Transmission Control Protocol (TCP), has been playing an important role in supporting network applications. However, it still exhibits many open issues. Most of AQM algorithms only deploy a single-queue structure that cannot differentiate flows and easily leads to unfairness. Moreover, the parameter settings of AQM are often static, making them difficult to adapt to the dynamic network environments. In this paper, we propose a general framework for designing "self-tuning" queue management (SQM), which is adaptive to the changing environments and provides fair congestion control among flows. We first present a general architecture of SQM with fair queueing and propose a general fluid model to analyze it. To adapt to the stochastic environments, we formulate a stochastic network utility maximization (SNUM) problem, and utilize online convex optimization (OCO) and control theory to develop a distributed SQM algorithm which can self-tune different queue weights and control parameters. Numerical and packet-level simulation results show that our SQM algorithm significantly improves queueing delay and fairness among flows.