29 research outputs found

    The multidriver: A reliable multicast service using the Xpress Transfer Protocol

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    A reliable multicast facility extends traditional point-to-point virtual circuit reliability to one-to-many communication. Such services can provide more efficient use of network resources, a powerful distributed name binding capability, and reduced latency in multidestination message delivery. These benefits will be especially valuable in real-time environments where reliable multicast can enable new applications and increase the availability and the reliability of data and services. We present a unique multicast service that exploits features in the next-generation, real-time transfer layer protocol, the Xpress Transfer Protocol (XTP). In its reliable mode, the service offers error, flow, and rate-controlled multidestination delivery of arbitrary-sized messages, with provision for the coordination of reliable reverse channels. Performance measurements on a single-segment Proteon ProNET-4 4 Mbps 802.5 token ring with heterogeneous nodes are discussed

    A formal protocol test procedure for the Survivable Adaptable Fiber Optic Embedded Network (SAFENET)

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    This thesis focuses upon a new method for verifying the correct operation of a complex, high speed fiber optic communication network. These networks are of growing importance to the military because of their increased connectivity, survivability, and recohttp://archive.org/details/aformalprotocolt1094539864Lieutenant, United States NavyApproved for public release; distribution is unlimited

    Space Station Freedom data management system growth and evolution report

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    The Information Sciences Division at the NASA Ames Research Center has completed a 6-month study of portions of the Space Station Freedom Data Management System (DMS). This study looked at the present capabilities and future growth potential of the DMS, and the results are documented in this report. Issues have been raised that were discussed with the appropriate Johnson Space Center (JSC) management and Work Package-2 contractor organizations. Areas requiring additional study have been identified and suggestions for long-term upgrades have been proposed. This activity has allowed the Ames personnel to develop a rapport with the JSC civil service and contractor teams that does permit an independent check and balance technique for the DMS

    Network time : synchronisation in real time distributed computing systems

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    In the past, network clock synchronization has been sufficient for the needs of traditional distributed systems, for such purposes as maintaining Network File Systems, enabling Internet mail services and supporting other applications that require a degree of clock synchronization. Increasingly real time systems arc requiring high degrees of time synchronization. Where this is required, the common approach up until now has been to distribute the clock to each processor by means of hardware (e.g. GPS and cesium clocks) or to distribute time by means of an additional dedicated timing network. Whilst this has proved successful for real time systems, the use of present day high speed networks with definable quality of service from the protocol layers has lead to the possibility of using the existing data network to distribute the time. This thesis demonstrates that by using system integration and implementation of commercial off the shelf (COTS) products it is possible to distribute and coordinate the time of the computer time clocks to microsecond range. Thus providing close enough synchronization to support real time systems whilst avoiding the additional time, infrastructure and money needed to build and maintain a specialized timing network

    Cyber Security in the Maritime Industry: A Systematic Survey of Recent Advances and Future Trends

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    The paper presents a classification of cyber attacks within the context of the state of the art in the maritime industry. A systematic categorization of vessel components has been conducted, complemented by an analysis of key services delivered within ports. The vulnerabilities of the Global Navigation Satellite System (GNSS) have been given particular consideration since it is a critical subcategory of many maritime infrastructures and, consequently, a target for cyber attacks. Recent research confirms that the dramatic proliferation of cyber crimes is fueled by increased levels of integration of new enabling technologies, such as IoT and Big Data. The trend to greater systems integration is, however, compelling, yielding significant business value by facilitating the operation of autonomous vessels, greater exploitation of smart ports, a reduction in the level of manpower and a marked improvement in fuel consumption and efficiency of services. Finally, practical challenges and future research trends have been highlighted

    Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 2: Army fault tolerant architecture design and analysis

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    Described here is the Army Fault Tolerant Architecture (AFTA) hardware architecture and components and the operating system. The architectural and operational theory of the AFTA Fault Tolerant Data Bus is discussed. The test and maintenance strategy developed for use in fielded AFTA installations is presented. An approach to be used in reducing the probability of AFTA failure due to common mode faults is described. Analytical models for AFTA performance, reliability, availability, life cycle cost, weight, power, and volume are developed. An approach is presented for using VHSIC Hardware Description Language (VHDL) to describe and design AFTA's developmental hardware. A plan is described for verifying and validating key AFTA concepts during the Dem/Val phase. Analytical models and partial mission requirements are used to generate AFTA configurations for the TF/TA/NOE and Ground Vehicle missions

    Spacelab system analysis: A study of the Marshall Avionics System Testbed (MAST)

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    An analysis of the Marshall Avionics Systems Testbed (MAST) communications requirements is presented. The average offered load for typical nodes is estimated. Suitable local area networks are determined

    Spacelab system analysis: A study of communications systems for advanced launch systems

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    An analysis of the required performance of internal avionics data bases for future launch vehicles is presented. Suitable local area networks that can service these requirements are determined
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