Institute for Systems Research Technical Reports

Permanent URI for this collectionhttp://hdl.handle.net/1903/4376

This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.

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Author: search.filters.author.Baras, John S.Subject: search.filters.subject.Internet

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    A Simulation Study of Enhanced TCP/IP Gateways for Broadband Internet over Satellite
    (1999) Karir, Manish; Liu, Mingyan D.; Barrett, Bradley A.; Baras, John S.; Baras, John S.; ISR; CSHCN
    The demand for Internet bandwidth has been growing rapidlyover the years and the use of high-bandwidth satellites has been proposed as one possible solution to meet the increasingdemand.

    However, there are certain performance problems withproviding Internet over satellite due to the nature of TCP/IP protocol suite and the satellite link characteristics. In this paper, we describe a simulation study of an architecture for improving the performance of TCP/IP over satellite links.

    On each end of the satellite link, there are gateways that split the TCP connection so that the satellite link is transparent to the end hosts.

    The split TCP connection over the satellite segment is then optimized.TCP congestion control is maintained on each segment of the split connection.

    We simulated such an architecture in OPNET and present results showing improved throughput over the satellite link.

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    Internet Service via Broadband Satellite Networks
    (1999) Bharadwaj, Vijay G.; Baras, John S.; Butts, Norman P.; Baras, John S.; ISR; CSHCN
    The demand for Internet bandwidth has grown rapidly in the past few years. A new generation of broadband satellite constellations promises to provide high speed Internet connectivity to areas not served by optical fiber, cable or other high speed terrestrial connections. However, using satellitelinks to supply high bandwidth has been difficult due to problems with inefficient performance of the Internet's TCP/IP protocol suite over satellite. We describe an architecture for improving the performance of TCP/IP protocols over heterogeneous network environments, especially networks containing satellite links. The end-to-end connection is split into segments, and the protocol on the satellite segment is optimized for the satellite link characteristics. TCP congestion control mechanisms are maintained on each segment, with some coupling between the segments to produce the effect of end-to-end TCP flow control. We have implemented this design and present results showing that using such gateways can improve throughput for individual connections by a large factor over paths containing a satellite link.

    The research and scientific content in this material has been published in the Proceedings of the SPIE, vol. 3528, February 1999, 169-180.
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    An Architecture for Internet Service via Broadband Satellite Networks
    (1999) Bharadwaj, Vijay G.; Baras, John S.; Butts, Norman P.; Baras, John S.; ISR; CSHCN
    High bandwidth satellites hold out the promise of a rapidly deployablecommunications infrastructure with a natural support for mobility. However,the Transmission Control Protocol (TCP), widely used in the Internet, performspoorly over satellite links, and this presents an obstacle to thedeployment of such systems. We present an architecture that overcomesthese problems and provides an approach to building complex heterogeneousnetworks from simple units. We also present some results from our initialimplementation, which uses TCP connection splitting to improve TCPperformance over satellite links.