A Generalized Framework of Linear Multivariable Control

15.5 Conclusions and further discussions

Control theory provides a powerful mathematical tool for describing dynamic systems. It lends itself to modeling congestion control—the interacting function of TCP and AQM is a perfect example of a typical “closed loop” system that can be described in control theoretic terms. However, control theory has had to be extended to model the interactions between multiple control loops like the multicast communication system in the Internet, or even a huge number of control loops with extremely complex interactions inside the loops and among the loops. The latter is referred to as the complex network, in which the interactions among the elements of the network are neither purely regular nor purely random.