Abstract-The Rapidly Deployable Radio Network (RDRN) is an architecture and experimental system to develop and evaluate hardware and software components suitable for implementing mobile, rapidly deployable, and adaptive wireless communications systems. The driving application for the RDRN is the need to quickly establish a communications infrastructure following a natural disaster, during a law enforcement activity, or rapid deployment of military force. The RDRN project incorporates digitally controlled antenna beams, programmable radios, adaptive protocols at the link layer, and mobile node management. This paper describes the architecture for the Rapidly Deployable Radio Network and a prototype system built to evaluate key system components.

This paper describes performance measurements taken in the MAGIC gigabit testbed relating to the performance of TCP in wide area ATM networks. The behavior of TCP with and without cell level pacing is studied. In particular, we focus on results that indicate that the TCP rate control mechanism alone is inadequate for congestion avoidance and control in wide-area gigabit networks. We also present results showing that TCP augmented by cell-level pacing addresses these problems and allows the full bandwidth capacity to be utilized. These results demonstrate the viability of high performance distributed systems based on wide area ATM networks given the proper ATM traffrc management infrastructure. 1: IntroductionThe behavior of the Transmission Control Protocol (TCP) [9J has been studied by a variety of authors [3,5,7,11,12, 161. Understanding TCP performance in networks based on SONET and ATM is of fundamental importance to the evolution of the existing national infrastructure to higher capacities, and hence to the growth of high performance distributed computing in wide area networks. This paper presents results from experiments conducted on the MAGIC gigabit testbed. During the initial testing of the MAGIC terrain visualization application [lo], observed throughput was less than that expected given the link capacity, processing capabilities of the hosts involved, and individual host to host throughputtests. The experiments we report in this paper were performed in an attempt to explain these anomalies and find solutions to the throughput limitations. We focus on results that indicate that the TCP rate control mechanism alone may be inadequate for congestion avoidance and control in wide-area gigabit networks. We also present results showing that TCP augmented by celllevel pacing addresses these problems and allows the full bandwidth capacity to be utilized. 1.1: Overview of ResultsThe default TCP/IP performance over congested ATM networks is poor. These congestion and buffer overflow conditions, which are caused by bandwidth mismatches or mulThe authors can be contacted via tiple sources contending for the same link, are extremely common in data networks with high performance. A number of simulation studies [5, 111 have predicted this behavior, and the measurements from MAGIC confirm this. Simulations [5] as well as preliminary experiments at the Digital Equipment Corporation Systems Research Center and in MAGIC indicate that strict link-level ATM flow control will avoid congestion-induced cell loss and provide excellent TCP throughput in local area networks, although this may be a extremely expensive solution in wide area networks. The experimental results from MAGIC address several issues. First, is TCP rate control effective in wide area ATM networks as cumently implemented? Second, if TCP rate control is not adequate, why is this the case? Third, can solutions at the ATM cell level, in particular tr&c pacing, be used to improve performance? 2: Background 2.1: MAGIC NetworkThe Multidimensional Applications and...

The pervasive availability and wide usage of wireless networks with different kinds of topologies, techniques and protocol suites have brought with them a need to improve security mechanisms. The design, development and evaluation of security techniques must begin with a thorough analysis of the requirements and a deeper understanding of the approaches that are practical within the system constraints. In this paper, we investigate the recent advances in wireless security from theoretical foundations to evaluation techniques, from network level management to end user trust inference and from individual protocol to hybrid systems. We identify the open security issues associated with trust, management, interoperation and measurement. These problems, whose solutions are different in nature and scale from their companions in wired networks, must be properly addressed to establish confidence in the security of wireless networking environments.

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