SUMMARY
For a class of uncertain discrete network systems, a sliding mode control algorithm is presented for active queue management (AQM) in order to solve the problem of congestion control in transmission control protocol (TCP) communication. First, the sliding surface is designed based on linear matrix inequality (LMI) technique. Then, we analyze the mechanism of chattering for the discrete-time exponential approximation law, a modified one is presented and applied to the network systems. Simulation results demonstrate that the proposed controller has good stability and robustness with respect to the uncertainties of the number of active TCPsessions, link capacity and the round-trip time.