This thesis presents a control module for software edge routers, called Receive Window Modulation - RWM. Its purpose is to limit congestion phenomena occurring in the network, which cause buffering and packet losses in any of intermediate routers along the path between the end points of an Internet connection. The controller improves end-to-end TCP performance, latency and fairness. It can be deployed in corporate edge routers, so that it does not need any end-point modification. The receiver’s TCP advertised window is modified based on the product of two different estimations: the round-trip time of the TCP connection and the path Available Bandwidth.