682 research outputs found

    Deep Space Network information system architecture study

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    The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control

    Towards an unified experimentation framework for protocol engineering

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    The design and development process of complex systems require an adequate methodology and efficient instrumental support in order to early detect and correct anomalies in the functional and non-functional properties of the solution. In this article, an Unified Experimentation Framework (UEF) providing experimentation facilities at both design and development stages is introduced. This UEF provides a mean to achieve experiment in both simulation mode with UML2 models of the designed protocol and emulation mode using real protocol implementation. A practical use case of the experimentation framework is illustrated in the context of satellite environment

    Re-feedback: freedom with accountability for causing congestion in a connectionless internetwork

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    This dissertation concerns adding resource accountability to a simplex internetwork such as the Internet, with only necessary but sufficient constraint on freedom. That is, both freedom for applications to evolve new innovative behaviours while still responding responsibly to congestion; and freedom for network providers to structure their pricing in any way, including flat pricing. The big idea on which the research is built is a novel feedback arrangement termed ‘re-feedback’. A general form is defined, as well as a specific proposal (re-ECN) to alter the Internet protocol so that self-contained datagrams carry a metric of expected downstream congestion. Congestion is chosen because of its central economic role as the marginal cost of network usage. The aim is to ensure Internet resource allocation can be controlled either by local policies or by market selection (or indeed local lack of any control). The current Internet architecture is designed to only reveal path congestion to end-points, not networks. The collective actions of self-interested consumers and providers should drive Internet resource allocations towards maximisation of total social welfare. But without visibility of a cost-metric, network operators are violating the architecture to improve their customer’s experience. The resulting fight against the architecture is destroying the Internet’s simplicity and ability to evolve. Although accountability with freedom is the goal, the focus is the congestion metric, and whether an incentive system is possible that assures its integrity as it is passed between parties around the system, despite proposed attacks motivated by self-interest and malice. This dissertation defines the protocol and canonical examples of accountability mechanisms. Designs are all derived from carefully motivated principles. The resulting system is evaluated by analysis and simulation against the constraints and principles originally set. The mechanisms are proven to be agnostic to specific transport behaviours, but they could not be made flow-ID-oblivious

    情報セントリックIoTサーベランスシステムに関する研究

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    早大学位記番号:新8269早稲田大

    Reflections on Active Networking

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    Interactions among telecommunications networks, computers, and other peripheral devices have been of interest since the earliest distributed computing systems. A key architectural question is the location (and nature) of programmability. One perspective, that examined in this paper, is that network elements should be as programmable as possible, in order to build the most flexible distributed computing systems. This paper presents my personal view of the history of programmable networking over the last two decades, and in the spirit of vox audita perit, littera scripta manet , includes an account of how what is now called Active Networking came into being. It demonstrates the deep roots Active Networking has in the programming languages, networking and operating systems communities, and shows how interdisciplinary approaches can have impacts greater than the sums of their parts. Lessons are drawn both from the broader research agenda, and the specific goals pursued in the SwitchWare project. I close by speculating on possible futures for Active Networking

    Netodyssey: a framework for real-time windowed analysis of network traffic

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    Traffic monitoring and analysis is of critical importance for managing and designing modern computer networks, and constitutes nowadays a very active research field. In most of their studies, researchers use techniques and tools that follow a statistical approach to obtain a deeper knowledge about the traffic behaviour. Network administrators also find great value in statistical analysis tools. Many of those tools return similar metrics calculated for common properties of network packets. This dissertation presents NetOdyssey, a framework for the statistical analysis of network traffic. One of the crucial points of differentiation of NetOdyssey from other analysis frameworks is the windowed analysis philosophy behind NetOdyssey. This windowed analysis philosophy allows researchers who seek for a deeper knowledge about networks, to look at traffic as if looking through a window. This approach is crucial in order to avoid the biasing effects of statistically looking at the traffic as a whole. Small fluctuations and irregularities in the network can now be analyzed, because one is always looking through window which has a fixed size: either in number of observations or in the temporal duration of those observations. NetOdyssey is able to capture live traffic from a network card or from a pre-collected trace, thus allowing for real-time analysis or delayed and repetitive analysis. NetOdyssey has a modular architecture making it possible for researchers with reduced programming capabilities to create analysis modules which can be tweaked and easily shared among those who utilize this framework. These modules were thought so that their implementation is optimized according to the windowed analysis philosophy behind NetOdyssey. This optimization makes the analysis process independent from the size of the analysis window, because it only contemplates the observations coming in and going out of this window. Besides presenting this framework, its architecture and validation, the present Dissertation also presents four different analysis modules: Average and Standard deviation, Entropy, Auto-Correlation and Hurst Parameter estimators. Each of this modules is presented and validated throughout the present dissertation.Fundação para a Ciência e a Tecnologia (FCT

    Location and routing optimization protocols supporting internet host mobility

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    PhD ThesisWith the popularity of portable computers and the proliferation of wireless networking interfaces, there is currently a great deal of interest in providing IP networking support for host mobility using the Internet as a foundation for wireless networking. Most proposed solutions depend on a default route through the mobile host's horne address, which makes for unnecessarily long routes. The major problem that this gives rise to is that of finding an efficient way of locating and routing that allows datagrams to be delivered efficiently to moving destinations whilst limiting costly Internet-wide location updates as much as possible. Two concepts - "local region" and "patron service" - are introduced based on the locality features of the host movement and packet traffic patterns. For each mobile host, the local region is a set of designated subnetworks within which a mobile host often moves, and the patrons are the hosts from which the majority of traffic for the mobile host originated. By making use of the hierarchical addressing and routing structure of Internet, the two concepts are used to confine the effects of a host moving, so location updates are sent only to a designated host moving area and to those hosts which are most likely to call again, thus providing nearly optimal routing for most communication. The proposed scheme was implemented as an IP extension using a network simulator and evaluated from a system performance point of view. The results show a significant reduction in the accumulated communication time along with improved datagram tunneling, as compared with its extra location overhead. In addition, a comparison with another scheme shows that our functionality is more effective both for location update and routing efficiency. The scheme offers improved network and host scalability by isolating local movement from the rest of the world, and provides a convenient point at which to perform administration functions
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