Asymmetric Internet access over satellite-terrestrial networks

DirecPC's Turbo Internet is a low-cost hybrid high-speed digital transmission system which uses receive-only satellite links for downstream data delivery and public telephone networks at modern speeds to provide the upstream communications path. One of the services provided is high-speed Internet access based on an asymmetric TCP/IP protocol. Our principle objective is to lower cost and efficiently provide high bandwidth access to Internet services such as file transfer, the World Wide Web, and the MBONE. In the initial protocol implementation, we achieved four times higher throughput than that of today's high-speed modems alone. This throughput can be further enhanced. This paper presents two techniques, TCP spoofing and selective acknowledgment dropping, which significantly increase the overall throughput of the hybrid network. Our approach does not require any modification to the TCP/IP protocol stacks on the end hosts. The solutions proposed in this paper could be used to improve TCP/IP performance of other hybrid networks which have the disadvantage of high bandwidth-delay products and/or low bandwidth-return paths. (Author)