Abstract: Active queue management (AQM) is one of the main congestion control methods in IP network. In this paper we systematically analyze the architecture of the end-to-end congestion control schemes with AQM from the control-theoretic point of view. A transfer function of a simplified network's model is introduced. Based on the model, the configuration of RED and some other AQM algorithms are discussed. Finally we propose some future researches including the precision of network models and robustness of the control algorithms.