The paper presents an IP-based broadband satellite access (BSA) network architecture for interactive multimedia services with an emphasis on the return link (upstream direction). Dynamic capacity allocation (DCA) strategies based on the Combined Free and Demand Assignment Multiple Access (CFDAMA) scheme to support the Digital Video Broadcasting-Return Channel via Satellite (DVB-RCS) standard and Differentiated Services (DiffServ) architecture in order to achieve short delay and different QoS requirements are proposed. DCA scheduling algorithms and multiple-queue user terminal structures are presented. Simulation results on the traffic performance for various traffic loads, types and conditions confirm the effectiveness of the proposed structures. Copyright (C) 2003 John Wiley Sons, Ltd.