Master of Science

Bibliography: pages 61-66. / This dissertation addresses system architecture concepts for the implementation of real-time distributed systems. In particular, it addresses the requirements of a specific mission and real-time critical distributed system application as this exemplifies most of the issues of concern. Of specific significance is the integration of real-time distributed data services into a platform-wide Information Management Infrastructure. The dissertation commences with an overview of the system-level allocated requirements. Derived requirements for an Information Management Infrastructure (IMI) are then determined. A generic system architecture is then presented in terms of the allocated and derived requirements. A specific topology, based on this architecture, as well as available technology, is described. The scalability of the architecture to -different platforms, including non-surface platforms, is discussed. As financial considerations are an important design driver and constraint, some anticipated order-of-magnitude system acquisition costs for a range of system complexities and configurations are briefly reviewed. Finally some conclusions and recommendations within the context of the allocated and derived requirements, as well as the RSA's politico-economic environment, are offered.

Bibliography: pages 77-80. / This is a study of the simulated performance of two local area networks, Ethernet and the MAP network, respectively based on the IEEE standards 802.3 and 802.4. The simulation language chosen is of the discrete event type rather than the more usual analytical model. This is done in order to observe the interaction between the various entities of a network in order to gain a better understanding of the method of operation of such a system. The performance demanded of a node entity by the networks is determined. The performance of some commercially available hardware is derived from manufacturer's specifications and compared with that required by the network. It is found that there is a significant disparity, with the network requirements far exceeding that of the hardware capabilities. The simulation models developed are used to determine the performance of the networks both with and without the limitations imposed by currently available hardware. While the inclusion of the hardware performance causes little ·loss in performance for the Ethernet network, it has a highly detrimental effect on that of the MAP network. A possible solution is found to this limitation which requires minimal change to the existing protocol. The conclusions reached are that with currently available hardware a group of nodes are able to fully utilise the performance of the Ethernet LAN although a single pair of nodes is unable to do so. With regard to the MAP network, the network performance is limited by that of the node performance although this can be offset to a certain extent by careful choice of one of the protocol parameters, or modification of the hardware design.

Master of Science

Master of Engineering

<p>This project is a token bus local area network simulator written in Pascal on an IBM PC compatible. The simulator is written for the Microsoft Windows operating environment and makes use of a graphical user interface for controlling the simulation. The program is object-oriented to make use of the Borland ObjectWindows Windows interface and because of the suitability of object-oriented programming to graphics and simulation applications. All basic token bus network functionalities specified by the Institute Of Electrical And Electronics Engineers (IEEE) 802.4 token bus standard are implemented in the simulation plus an added function to resolve duplicate node addresses. The network nodes and bus are drawn using Windows' color graphics. The state of each node is represented by text as well as the color and style each node is drawn in. The frame being transmitted is shown as large text within the bus object on the screen. The direction of data transfer on the bus is shown graphically as is the current location of the token among the nodes.</p> <p> The user of the simulation has the ability make any node active, inactive, or passive, or to make any node fail. The user may make a node send data to one other node or many other random nodes. The addresses of the nodes may also be changed. The user may pause, step through, or continue the simulation, control the simulation speed, control the error rate of data on the bus, and produce a lost token scenario.</p> / Master of Science

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