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Science and Engineering Apprentice Program (SEAP) John BrandComputational and Information Sciences Directorate, ARL Approved for public release; distribution is unlimited. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

Network traffic has been reported to exhibit selfsimilar properties over time [Leland 19943 [Willinger 19951. This has been demonstrated under numerous circumstances involving high speed networks using civilian protocol suites. Self-similarity has also been reported to arise as a result of different network processes [Park 19961. Different network protocols have been shown to affect the degree of self-similarity in network traffic [Peha 19971. This is important because results indicate that the networks analyzed behave differently and exhibit different performance figures of merit depending on the traffic's degree of self-similarity. This investigation focuses on very low bandwidth tactical radio nets with military protocols.The U.S. Army Research Laboratory (ARL) has performed statistically controlled experiments to examine network performance using the combination of tactical communications protocols and tactical radios dnven by traffic with an arrival rate to the network that is generated from a Poisson distribution [Kaste 19921. These channels are of extremely low throughput and use communications protocols different from the widely used civilian protocols. The assumptions and conditions of the reported sources of selfsimilar behavior in civil experiments are compared to the very low bandwidth conditions and the effects of the protocols used in the ARL experiments.

The U.S. Army Research Laboratory (ARL) has conducted hardware-in-the loop experiments using combat net radios, message drivers, and tactical communications protocols to quantify the effects of network load parameters on the throughput and delay of a small combat radio net. A virtual reality network management tool will enhance the data analysis. The Situation Awareness Virtual Environment for Command, Control, and Communications (SAVEC3) Net Battle Management Tool is a software package developed by Quality Research, inc. under the auspices of the Small Business Innovative Research program. The tool currently displays a network level statistics window and individual statistics icons for each node and link. A statistical tool has been developed to provide performance analysis of the data stream beyond the simple net status currently available. In its present standalone form the statistical tool gets its input from data collected during previous experiments. The statistical tool has the capability to open individual link and node statistics windows displaying optional data such as the recent time history of link or node utilization, retransmit statistics, and effective throughput and message delay, thereby enhancing network performance analysis. The software calculates and logs network statistics continuously for all elements (nodes and links) supported by the processed data, and a choice of statistical measures can be displayed on demand for the operator. The software calculates the statistical measures both from the start time and from an operator-selectable time interval. The network statistics are presented by graphical displays in operator-selectable windows, as well as numerical boxes. Integration of the statistical package into the SAVEC3 Net Battle Management Tool is planned for summer FY99. This paper discusses the statistical tool in greater detail. BACKGROUND

Approved for public release; distribution is unlimited.ii REPORT DOCUMENTATION PAGE Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.