Improving performance of TCP-based applications over DVB-RCS links

DVB-RCS links, as well as most of VSAT systems, to improve TCP performance usually consider a PEP solution. The SatLabs group of the European Space Agency issued I-PEP, selecting SCPS-TP as transport protocol, which supports two congestion control schemes: TCP Vegas (default) and van Jacobson’s Slow Start and Congestion Avoidance. In both cases the most popular TCP-based applications, i.e. Web browsing and e-mail, achieve very poor performance especially when DAMA schemes run at the MAC layer. In this frame, TCP Noordwijk has been specifically designed to optimize performance of short TCP- based data transfers over DVB-RCS DAMA links, meeting the requirement to be compatible with I-PEP specifications. This paper presents an overview of TCP-based application criticalities over DVB-RCS links and shows how TCP Noordwijk improves performance.