Self-Tuning Utility-Based Controller for End-to-End Congestion in the Internet

In this paper, we design a self-tuning utility- based controller for end-to-end congestion in the IP (Internet protocol)-based Internet. Multiple controlled sources transmit the packets through a series of AQM (active queue management) routers into their destinations simultaneously and share the limited bandwidth of the Internet. Each AQM router runs the RED (random early detection) algorithm that uses ECN (explicit congestion notification) packet marking strategy to provide the link congestion information through IP packets. A self-tuning utility-based controller is placed in every source node to regulate source transmission rate based on the feedback route congestion information from the AQM routers through ACK packets. The pole placement technique in classical control theory is used to allow the user to achieve good transient network performance. By assigning a proper interval of damping ratio zeta, ach controller self-tunes only when the change of network parameters drifts zeta outside its specified interval. Our simulations demonstrate the stability of the Internet achieved by our self-tuning utility-based congestion controller.