161 research outputs found

    A Performance evaluation of several ATM switching architectures

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    The goal of this thesis is to evaluate the performance of three Asynchronous Transfer Mode switching architectures. After examining many different ATM switching architectures in literature, the three architectures chosen for study were the Knockout switch, the Sunshine switch, and the Helical switch. A discrete-time, event driven system simulator, named ProModel, was used to model the switching behavior of these architectures. Each switching architecture was modeled and studied under at least two design configurations. The performance of the three architectures was then investigated under three different traffic types representative of traffic found in B-ISDN: random, constant bit rate, and bursty. Several key performance parameters were measured and compared between the architectures. This thesis also explored the implementation complexities and fault tolerance of the three selected architectures

    Satellite B-ISDN traffic analysis

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    The impact of asynchronous transfer mode (ATM) traffic on the advanced satellite broadband integrated services digital network (B-ISDN) with onboard processing is reported. Simulation models were built to analyze the cell transfer performance through the statistical multiplexer at the earth station and the fast packet switch at the satellite. The effectiveness of ground ATM cell preprocessing was established, as well as the performance of several schemes for improving the down-link beam utilization when the space segment employs a fast packet switch

    Information Switching Processor (ISP) contention analysis and control

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    Future satellite communications, as a viable means of communications and an alternative to terrestrial networks, demand flexibility and low end-user cost. On-board switching/processing satellites potentially provide these features, allowing flexible interconnection among multiple spot beams, direct to the user communications services using very small aperture terminals (VSAT's), independent uplink and downlink access/transmission system designs optimized to user's traffic requirements, efficient TDM downlink transmission, and better link performance. A flexible switching system on the satellite in conjunction with low-cost user terminals will likely benefit future satellite network users

    On-board B-ISDN fast packet switching architectures. Phase 2: Development. Proof-of-concept architecture definition report

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    For the next-generation packet switched communications satellite system with onboard processing and spot-beam operation, a reliable onboard fast packet switch is essential to route packets from different uplink beams to different downlink beams. The rapid emergence of point-to-point services such as video distribution, and the large demand for video conference, distributed data processing, and network management makes the multicast function essential to a fast packet switch (FPS). The satellite's inherent broadcast features gives the satellite network an advantage over the terrestrial network in providing multicast services. This report evaluates alternate multicast FPS architectures for onboard baseband switching applications and selects a candidate for subsequent breadboard development. Architecture evaluation and selection will be based on the study performed in phase 1, 'Onboard B-ISDN Fast Packet Switching Architectures', and other switch architectures which have become commercially available as large scale integration (LSI) devices

    An Aggregate Scalable Scheme for Expanding the Crossbar Switch Network; Design and Performance Analysis

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    New computer network topology, called Penta-S, is simulated. This network is built of cross bar switch modules. Each module connects 32 computer nodes. Each node has two ports, one connects the node to the crossbar switch module and the other connects the node to a correspondent client node in another module through a shuffle link. The performance of this network is simulated under various network sizes, packet lengths and loads. The results are compared with those obtained from Macramé project for Clos multistage interconnection network and 2D-Grid network. The throughput of Penta-S falls between the throughput of Clos and the throughput of 2D-Grid networks. The maximum throughput of Penta-S was obtained at packet length of 128 bytes. Also the throughput grows linearly with the network size. On the opposite of Clos and 2D-Grid networks, the per-node throughput of Penta-S improves as the network size grows. The per-packet latency proved to be better than that of Clos network for large packet lengths and high loads. Also the packet latency proved to be nearly constant against various loads. The cost-efficiency of Penta-S proved to be better than those of 2D-Grid and Clos networks for large number of nodes (>200 nodes in the case of 2D-Grid and >350 nodes in the case of Clos).On the opposite of other networks, the cost-efficiency of Penta-S grows as its size grows. So this topology suits large networks and high traffic loads

    The Design, modeling and simulation of switching fabrics: For an ATM network switch

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    The requirements of today\u27s telecommunication systems to support high bandwidth and added flexibility brought about the expansion of (Asynchronous Transfer Mode) ATM as a new method of high-speed data transmission. Various analytical and simulation methods may be used to estimate the performance of ATM switches. Analytical methods considerably limit the range of parameters to be evaluated due to extensive formulae used and time consuming iterations. They are not as effective for large networks because of excessive computations that do not scale linearly with network size. One the other hand, simulation-based methods allow determining a bigger range of performance parameters in a shorter amount of time even for large networks. A simulation model, however, is more elaborate in terms of implementation. Instead of using formulae to obtain results, it has to operate software or hardware modules requiring a certain amount of effort to create. In this work simulation is accomplished by utilizing the ATM library - an object oriented software tool, which uses software chips for building ATM switches. The distinguishing feature of this approach is cut-through routing realized on the bit level abstraction treating ATM protocol data units, called cells, as groups of 424 bits. The arrival events of cells to the system are not instantaneous contrary to commonly used methods of simulation that consider cells as instant messages. The simulation was run for basic multistage interconnection network types with varying source arrival rate and buffer sizes producing a set of graphs of cell delays, throughput, cell loss probability, and queue sizes. The techniques of rearranging and sorting were considered in the simulation. The results indicate that better performance is always achieved by bringing additional stages of elements to the switching system

    Architectural design options for ATM switches

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