Internet represents a shared resource, wherein users contend for the finite network bandwidth. Contention among independent user demands can result in congestion, which, in turn, leads to long queuing delays, packet losses or both. In the Internet, there are two mechanisms which deal with congestion, the end-to-end mechanism which is achieved by the Transmission Control Protocol (TCP) and the intermediate nodes algorithms such as Active Queue Management (AQM) in routers. In this thesis, a combined model of TCP and AQM (TCP/AQM) is presented and first simulated without controller. The results show that it is unable to track the desired queue size. So to get better tracking performance the Proportional Integral (PI) controller is used as AQM in the router queue, which shows good tracking performance but with overshoot 33% and settling time 35 sec. So to reduce the overshoot and speed up the system response a Linear Quadratic_servo (LQ_servo) controller was designed based on linear control theory for TCP/AQM router. The design specifications, depends on choosing weighting matrices Q and R .Firstly, Q and R are selected by a trial- and- error process method but to get the best controller parameter the Genetic Algorithm (GA) or Particle Swarm Optimization (PSO) algorithm was used , where using GA and (PSO) enhance overall system response . The simulation results for TCP/AQM model are presented in MATLAB version 7.0. The controller simulation result shows the ability of the LQ-servo controller to track the desired queue size with settling time 8 sec and it also shows that the use of PSO to select Q and Rreduced the negative overshoot and the computational time compared with GA by 75%.