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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    The Acts Experiments program at the Center for Satellite and Hybrid Communication Networks
    (1997) Friedman, Daniel E.; Gupta, Sonjai K.; Zhang, C.; Ephremides, Anthony; ISR; CSHCN
    This paper describes experiments conducted over ACTS and the associated T1~VSAT terminal. The experiments were motivated by the commercial potential of low-cost receive-only satellite terminals that can operate in a hybrid network environment, and by the desire to demonstrate frame relay technology over satellite networks. The first experiment tested highly adaptive methods of satellite bandwidth allocation in an integrated voice- data service environment. The second involved comparison of FEC and ARQ methods of error control for satellite communication with emphasis on the advantage that a hybrid architecture provides, especially in the case of multicasts. Finally, the third experiment demonstrated hybrid access to databases through the use of Mosaic and compared the performance of internetworking protocols for interconnecting LANs via satellite. A custom unit termed Frame Relay Access Switch (FRACS) was developed by COMSAT Laboratories for these experiments; the preparation and conduct of these experiments involved a total of twenty people from the University of Maryland, the University of Colorado, and COMSAT Laboratories, from late 1992 through 1995.
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    Advanced Orbiting Systems Data Generator/Simulator: A Functional Description of the Software (Version 3)
    (1994) Baras, John S.; Atallah, George C.; Fuja, Tom E.; Murad, A.; Jang, Kap D.; ISR; CSHCN
    The Advanced Orbiting System (AOS) Data Generator/Simulator is a software implementation of the transmitter (data generation) section of the CCSDS Recommendation 701.0-B-2 for Advanced Orbiting Systems: Networks and Data Links. An object-oriented approach to the simulation of a complex, high-performance communication protocol, it makes full use of the concepts of data-encapsulation and inheritance to ease implementation. The backbone of the software is a general-purpose packet description and generation module that may be used as part of any packet- based simulation software. The user-interface to the program is in the form of a command-language, designed to ease the process of generation of large, multiple data-streams. The output of the program may be configured for interpretation by a graphical user interface (for visual inspection of the data), or as a bit-stream suitable for further processing. This paper consists of three sections. The first two sections provide a brief, yet comprehensive description of the above CCSDS Recommendation. The various kinds and qualities of user-services, data units involved, and data-paths defined by the protocol are discussed. The different qualities of service (in terms or data reliability) available to the user (and the error-control schemes used to provide them) are also discussed. The last section describes the structure and user-interfaces of the AOS Data Generator/Simulator.