In this paper a new mechanism for providing an assured rate to a long-lived TCP flow is proposed. The mechanism is called TCP rate controller (TRC) and operates as a traffic conditioner at the edge of a network. The TRC seeks to achieve the requested rate by imposing well directed drops and (artificial) delays on the flow’s packets. The choice of drop probability and delay is based on an analytical model of TCP sending behavior. It is shown in a simulation study that the TRC performs well over a broad range of requested rates and network RTTs.