Adaptive Congestion Control in Computer Networks

The congestion control in computer network is a problem of controlling a specific object such as a computer network. Several attempts have been made to develop congestion controllers, mostly using linear control theory. The conventional controller PID generally does not work well for nonlinear, uncertain, and time-delayed systems as computer networks. The paper provides an adaptation mechanism designed to prevent unstable behavior of the system, with fuzzy rules, and with an inference mechanism that identifies the possible sources of nonlinear behavior. The adaptation mechanism is designed to adjust PID controller tuning parameters when oscillatory behavior is detected. Tests in nonlinear and uncertainty conditions are performed.