Feedback control methods for router management

Several studies have considered control theory tools for traffic control in communication networks, including congestion control in internet protocol routers. In this work, classification of congestion control schemes and their mechanisms are discussed. Buffer and queue management mechanisms are compared. Dynamic transmission control protocol (TCP) model for single and multiple routers are derived and its stability behaviour is further examined. An observer-based feedback control design method is provided to address the traffic monitoring issue in TCP/active queue management (AQM) networks. Owing to several propagation delays and the queuing delay, the set TCP/AQM is modelled as a multiple delayed system of a particular form. Simulation studies are given to illustrate the analytical development for single and multi-routers.