In this paper, we propose nonlinear congestion controller for active queue
management of differentiated-services networks. Two important issues
in differentiated-services architecture are bandwidth guarantee and fair
sharing of unsubscribed bandwidth among TCP flows with and without bandwidth
reservation. The nonlinear congestion controller was composed fuzzy logic
controller and state feedback controller. The nonlinear congestion controller
methodology has been applied to a TCP network. We use NS-2 simulation to
demonstrate that the proposed control methodology achieves the desired behavior
of the network, and possesses important attributes.