On Transient Behavior Analysis of Random Early Detection Gateway using a Control Theoretic Approach

AQM (Active Queue Management) mechanisms support the end-to-end congestion control mechanism of TCP (Transmission Control Protocol). Several AQM mechanisms have been recently proposed and studied by many researchers. One of popular AQM mechanisms is the RED (Random Early Detection) gateway, which randomly discards arriving packets. Although its steady state performance has been fully investigated, its transient behavior has not been well understood. In our previous work, we have analyzed the transient behavior of the RED gateway for limited cases of TCP connection variations. In this paper, by extending our previous work, we analyze the transient behavior of the RED gateway for various types of TCP connection variations (e.g., intermittent arrival or continuous arrival of multiple TCP connections). We use a control theoretic approach, which is based on the transfer function describing the relation between input and output in frequency domain. By presenting several numerical and simulation results, we discuss how control parameters of the RED gateway affect its transfer behavior.