Despite the many research efforts at the transport layer (SCTP, DCCP, etc.), new innovations in that area hardly ever make it into the TCP/IP stacks of standard end systems. We believe that this is due to lack of a flexible interface to the application as well as a lack of transparency – a problem that could be solved by introducing a middleware above TCP/IP. In this paper we present the architecture of our middleware, and show the importance of congestion awareness by simulations. In addition, we explain how to force congestion control on existing applications using our middleware, show the benefits of doing so with simulations, and finally discuss the impact of our middleware towards a better utilization of the network and a more suitable service for the user software. Key words: congestion control, middleware, DCCP, protocols