The implementation of successful Assured Forwarding (AF) services according to the DiffServ framework remains a challenging problem today, despite the numerous proposals for AF PHB mechanisms and AF-based service implementations. In this work, we propose two modules, the TCP-Window Aware Marker (TWAM) and the Dynamic WRED (DWRED) mechanism for implementing the DiffServ AF PHB. We provide analytical models and an experimental evaluation in order to demonstrate how they succeed in enhancing the quality, increasing fairness, improving the performance and easing the deployment of a production- level AF-based service.