23 research outputs found
Service introduction in an active network
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 1999.Includes bibliographical references (p. 151-157).by David J. Wetherall.Ph.D
A methodical approach to performance measurement experiments : measure and measurement specification
This report describes a methodical approach to performance measurement experiments. This approach gives a blueprint for the whole trajectory from the notion of performance measures and how to define them via planning, instrumentation and execution of the experiments to interpretation of the results. The first stage of the approach, Measurement Initialisation, has been worked out completely. It is shown that a well-defined system description allows a procedural approach to defining performance measures and to identifying parameters that might affect it. For the second stage of the approach, Measurement Planning, concepts are defined that enable a clear experiment description or specification. It is highlighted what actually is being measured when executing an experiment. A brief example that illustrates the value of the method and a comparison with an existing method - that of Jain - complete this report
A study of the applicability of software-defined networking in industrial networks
173 p.Las redes industriales interconectan sensores y actuadores para llevar a cabo funciones de monitorización, control y protección en diferentes entornos, tales como sistemas de transporte o sistemas de automatización industrial. Estos sistemas ciberfísicos generalmente están soportados por múltiples redes de datos, ya sean cableadas o inalámbricas, a las cuales demandan nuevas prestaciones, de forma que el control y gestión de tales redes deben estar acoplados a las condiciones del propio sistema industrial. De este modo, aparecen requisitos relacionados con la flexibilidad, mantenibilidad y adaptabilidad, al mismo tiempo que las restricciones de calidad de servicio no se vean afectadas. Sin embargo, las estrategias de control de red tradicionales generalmente no se adaptan eficientemente a entornos cada vez más dinámicos y heterogéneos.Tras definir un conjunto de requerimientos de red y analizar las limitaciones de las soluciones actuales, se deduce que un control provisto independientemente de los propios dispositivos de red añadiría flexibilidad a dichas redes. Por consiguiente, la presente tesis explora la aplicabilidad de las redes definidas por software (Software-Defined Networking, SDN) en sistemas de automatización industrial. Para llevar a cabo este enfoque, se ha tomado como caso de estudio las redes de automatización basadas en el estándar IEC 61850, el cual es ampliamente usado en el diseño de las redes de comunicaciones en sistemas de distribución de energía, tales como las subestaciones eléctricas. El estándar IEC 61850 define diferentes servicios y protocolos con altos requisitos en terminos de latencia y disponibilidad de la red, los cuales han de ser satisfechos mediante técnicas de ingeniería de tráfico. Como resultado, aprovechando la flexibilidad y programabilidad ofrecidas por las redes definidas por software, en esta tesis se propone una arquitectura de control basada en el protocolo OpenFlow que, incluyendo tecnologías de gestión y monitorización de red, permite establecer políticas de tráfico acorde a su prioridad y al estado de la red.Además, las subestaciones eléctricas son un ejemplo representativo de infraestructura crítica, que son aquellas en las que un fallo puede resultar en graves pérdidas económicas, daños físicos y materiales. De esta forma, tales sistemas deben ser extremadamente seguros y robustos, por lo que es conveniente la implementación de topologías redundantes que ofrezcan un tiempo de reacción ante fallos mínimo. Con tal objetivo, el estándar IEC 62439-3 define los protocolos Parallel Redundancy Protocol (PRP) y High-availability Seamless Redundancy (HSR), los cuales garantizan un tiempo de recuperación nulo en caso de fallo mediante la redundancia activa de datos en redes Ethernet. Sin embargo, la gestión de redes basadas en PRP y HSR es estática e inflexible, lo que, añadido a la reducción de ancho de banda debida la duplicación de datos, hace difícil un control eficiente de los recursos disponibles. En dicho sentido, esta tesis propone control de la redundancia basado en el paradigma SDN para un aprovechamiento eficiente de topologías malladas, al mismo tiempo que se garantiza la disponibilidad de las aplicaciones de control y monitorización. En particular, se discute cómo el protocolo OpenFlow permite a un controlador externo configurar múltiples caminos redundantes entre dispositivos con varias interfaces de red, así como en entornos inalámbricos. De esta forma, los servicios críticos pueden protegerse en situaciones de interferencia y movilidad.La evaluación de la idoneidad de las soluciones propuestas ha sido llevada a cabo, principalmente, mediante la emulación de diferentes topologías y tipos de tráfico. Igualmente, se ha estudiado analítica y experimentalmente cómo afecta a la latencia el poder reducir el número de saltos en las comunicaciones con respecto al uso de un árbol de expansión, así como balancear la carga en una red de nivel 2. Además, se ha realizado un análisis de la mejora de la eficiencia en el uso de los recursos de red y la robustez alcanzada con la combinación de los protocolos PRP y HSR con un control llevado a cabo mediante OpenFlow. Estos resultados muestran que el modelo SDN podría mejorar significativamente las prestaciones de una red industrial de misión crítica
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Heterogeneous Cloud Systems Based on Broadband Embedded Computing
Computing systems continue to evolve from homogeneous systems of commodity-based servers within a single data-center towards modern Cloud systems that consist of numerous data-center clusters virtualized at the infrastructure and application layers to provide scalable, cost-effective and elastic services to devices connected over the Internet. There is an emerging trend towards heterogeneous Cloud systems driven from growth in wired as well as wireless devices that incorporate the potential of millions, and soon billions, of embedded devices enabling new forms of computation and service delivery. Service providers such as broadband cable operators continue to contribute towards this expansion with growing Cloud system infrastructures combined with deployments of increasingly powerful embedded devices across broadband networks. Broadband networks enable access to service provider Cloud data-centers and the Internet from numerous devices. These include home computers, smart-phones, tablets, game-consoles, sensor-networks, and set-top box devices. With these trends in mind, I propose the concept of broadband embedded computing as the utilization of a broadband network of embedded devices for collective computation in conjunction with centralized Cloud infrastructures. I claim that this form of distributed computing results in a new class of heterogeneous Cloud systems, service delivery and application enablement. To support these claims, I present a collection of research contributions in adapting distributed software platforms that include MPI and MapReduce to support simultaneous application execution across centralized data-center blade servers and resource-constrained embedded devices. Leveraging these contributions, I develop two complete prototype system implementations to demonstrate an architecture for heterogeneous Cloud systems based on broadband embedded computing. Each system is validated by executing experiments with applications taken from bioinformatics and image processing as well as communication and computational benchmarks. This vision, however, is not without challenges. The questions on how to adapt standard distributed computing paradigms such as MPI and MapReduce for implementation on potentially resource-constrained embedded devices, and how to adapt cluster computing runtime environments to enable heterogeneous process execution across millions of devices remain open-ended. This dissertation presents methods to begin addressing these open-ended questions through the development and testing of both experimental broadband embedded computing systems and in-depth characterization of broadband network behavior. I present experimental results and comparative analysis that offer potential solutions for optimal scalability and performance for constructing broadband embedded computing systems. I also present a number of contributions enabling practical implementation of both heterogeneous Cloud systems and novel application services based on broadband embedded computing
An Architectural Framework for Performance Analysis: Supporting the Design, Configuration, and Control of DIS /HLA Simulations
Technology advances are providing greater capabilities for most distributed computing environments. However, the advances in capabilities are paralleled by progressively increasing amounts of system complexity. In many instances, this complexity can lead to a lack of understanding regarding bottlenecks in run-time performance of distributed applications. This is especially true in the domain of distributed simulations where a myriad of enabling technologies are used as building blocks to provide large-scale, geographically disperse, dynamic virtual worlds. Persons responsible for the design, configuration, and control of distributed simulations need to understand the impact of decisions made regarding the allocation and use of the logical and physical resources that comprise a distributed simulation environment and how they effect run-time performance. Distributed Interactive Simulation (DIS) and High Level Architecture (HLA) simulation applications historically provide some of the most demanding distributed computing environments in terms of performance, and as such have a justified need for performance information sufficient to support decision-makers trying to improve system behavior.
This research addresses two fundamental questions: (1) Is there an analysis framework suitable for characterizing DIS and HLA simulation performance? and (2) what kind of mechanism can be used to adequately monitor, measure, and collect performance data to support different performance analysis objectives for DIS and HLA simulations? This thesis presents a unified, architectural framework for DIS and HLA simulations, provides details on a performance monitoring system, and shows its effectiveness through a series of use cases that include practical applications of the framework to support real-world U.S. Department of Defense (DoD) programs. The thesis also discusses the robustness of the constructed framework and its applicability to performance analysis of more general distributed computing applications
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QoSME: QoS Management Environment
Distributed multimedia applications are sensitive to the Quality of Service (QoS) delivered by underlying communication networks. For example, a video conference exchange can be very sensitive to the effective network throughput. Network jitter can greatly disrupt a speech stream. The main question this thesis addresses is how to adapt multimedia applications to the QoS delivered by the network and vice versa. Such adaptation is especially important because current networks are unable to assure the QoS required by applications and the latter is usually unprepared for periods of QoS degradation. This work introduces the QoS Management Environment (QoSME) that provides mechanisms for such adaptation. The main contributions of this thesis are: Language level abstractions for QoS management. The Quality Assurance Language (QuAL) in QoSME enables the specification of how to allocate, monitor, analyze, and adapt to delivered QoS. Applications can express in QuAL their QoS needs and how to handle potential violations. Automatic QoS monitoring. QoSME automatically generates the instrumentation to monitor QoS when applications use QuAL constructs. The QoSME runtime scrutinizes interactions among applications, transport protocols, and Operating Systems (OS) and collects in QoS Management Information Bases (MIBs) statistics on the QoS delivered. Integration of QoS and standard network management. A Simple Network Management Protocol (SNMP) agent embedded in QoSME provides QoS MIB access to SNMP managers. The latter can use this feature to monitor end-to-end QoS delivery and adapt network resource allocation and operations accordingly. A partial prototype of QoSME has been released for public access. It runs on SunOS 4.3 and Solaris 2.3 and supports communication on ATM adaptation layer, ST-II, UDP/IP, TCP/IP, and Unix internal protocols
Resource discovery for distributed computing systems: A comprehensive survey
Large-scale distributed computing environments provide a vast amount of heterogeneous computing resources from different sources for resource sharing and distributed computing. Discovering appropriate resources in such environments is a challenge which involves several different subjects. In this paper, we provide an investigation on the current state of resource discovery protocols, mechanisms, and platforms for large-scale distributed environments, focusing on the design aspects. We classify all related aspects, general steps, and requirements to construct a novel resource discovery solution in three categories consisting of structures, methods, and issues. Accordingly, we review the literature, analyzing various aspects for each category
High-Performance Modelling and Simulation for Big Data Applications
This open access book was prepared as a Final Publication of the COST Action IC1406 “High-Performance Modelling and Simulation for Big Data Applications (cHiPSet)“ project. Long considered important pillars of the scientific method, Modelling and Simulation have evolved from traditional discrete numerical methods to complex data-intensive continuous analytical optimisations. Resolution, scale, and accuracy have become essential to predict and analyse natural and complex systems in science and engineering. When their level of abstraction raises to have a better discernment of the domain at hand, their representation gets increasingly demanding for computational and data resources. On the other hand, High Performance Computing typically entails the effective use of parallel and distributed processing units coupled with efficient storage, communication and visualisation systems to underpin complex data-intensive applications in distinct scientific and technical domains. It is then arguably required to have a seamless interaction of High Performance Computing with Modelling and Simulation in order to store, compute, analyse, and visualise large data sets in science and engineering. Funded by the European Commission, cHiPSet has provided a dynamic trans-European forum for their members and distinguished guests to openly discuss novel perspectives and topics of interests for these two communities. This cHiPSet compendium presents a set of selected case studies related to healthcare, biological data, computational advertising, multimedia, finance, bioinformatics, and telecommunications
FlexWAFE - eine Architektur für rekonfigurierbare-Bildverarbeitungssysteme
Recently there has been an increase in demand for high-resolution digital media content in both cinema and television industries. Currently existing equipment does not meet the requirements, or is too costly. New hardware systems and new programming techniques are needed in order to meet the high-resolution, high-quality, image requirements and reduce costs. The industry seeks a flexible architecture capable of running multiple applications on top of standard off-the-shelf components, with reduced development time.
Until now, standard practice has been to develop specialized architectures and systems that target a single application. This has little flexibility and leads to high developments costs, every new application is designed almost from scratch.
Our focus was to develop an architecture that is suited to image stream processing and has the flexibility to run multiple applications using the same FPGA-based hardware platform. The novelty in our approach is that we reconfigure parts of the architecture at run-time, but without incurring in the time and added constraints penalty of FPGA-partial-reconfiguration techniques. The architecture uses a hierarchical control structure that is well suited to parallel processing, and allows single cycle latency reconfiguration of parts of the processing pipeline. This is achieved using relatively little resources for the distributed control structures.
To test the developed architecture a complex film-grain noise reduction algorithm was implemented on an off-the-shelf hardware platform developed by Thomson-Grass Valley. The system meet all the requirements and had very little load on the hierarchical control structures, there is growth headroom for much complexer control demands.
The architecture has been ported to other hardware platforms, and other applications have been implemented as well. The run-time reconfigurability has proven to be a key factor in the success of the FlexWAFE.Kürzlich gab es eine Zunahme der Nachfrage nach hochauflösenden digitalen Medieninhalten in den Kino- und Fernsehenindustrien. Derzeit vorhandene Systeme entsprechen nicht den Anforderungen, oder sind zu teuer. Neue Hardware-Systeme und neuer Programmiertechniken sind erforderlich, um den hochauflösenden, hochwertigen, Bildanforderungen zu genügen und Kosten zu verringern. Die Industrie sucht eine flexible Architektur zur Ausführung mehrerer Anwendungen auf Standard-Komponenten, mit reduzierten Entwicklungszeiten.
Bis jetzt ist gängige Praxis, spezialisierten Architektur und Systeme zu entwickeln, die eine einzelne Anwendung zielen. Dieses hat wenig Flexibilität und führt zu hohe Entwicklungskosten, jede neue Anwendung ist fast von Grund auf neu konzipiert.
Unser Fokus war es, eine für Bild Verarbeitung geeignet Architektur zu entwickeln dass die Flexibilität hat mehrere Anwendungen an dieselbe FPGA-basierte Hardware-Plattform zu laufen. Die Neuheit in unserem Ansatz ist, dass wir Teile der Architektur zur Laufzeit rekonfigurieren, aber, ohne das Zeit und constraints strafe von FPGA Partielle-Rekonfiguration-Techniken. Die Architektur verwendet eine hierarchische Kontrollstruktur, die zur parallel Verarbeitung gut geeignet ist, und Single-Cycle-Latenz Rekonfiguration von Teilen der Verarbeitungs-Pipeline ermöglicht. Dieses wird unter Verwendung relativ weniger Ressourcen für die verteiltes Steuerung Strukturen erzielt.
Um das entwickelte Architektur zu testen ein komplexer Film-Korn-Rauschunterdrückung Algorithmus wurde auf einer von Thomson-Grass Valley entwickelt standard Hardware-Plattform umgesetzt. Das System erfüllt alle Anforderungen und hatte sehr wenig Last auf den hierarchischen Kontrollstrukturen, es gibt viel Wachstum Spielraum für viel kompliziertere Steuerunganforderungen.
Die Architektur ist zu anderen Hardwareplattformen portiert worden, und andere Anwendungen wurden ebenfalls implementiert. Der Laufzeitreconfigurability ist ein Schlüsselfaktor im Erfolg des FlexWAFE gewesen
High-Performance Modelling and Simulation for Big Data Applications
This open access book was prepared as a Final Publication of the COST Action IC1406 “High-Performance Modelling and Simulation for Big Data Applications (cHiPSet)“ project. Long considered important pillars of the scientific method, Modelling and Simulation have evolved from traditional discrete numerical methods to complex data-intensive continuous analytical optimisations. Resolution, scale, and accuracy have become essential to predict and analyse natural and complex systems in science and engineering. When their level of abstraction raises to have a better discernment of the domain at hand, their representation gets increasingly demanding for computational and data resources. On the other hand, High Performance Computing typically entails the effective use of parallel and distributed processing units coupled with efficient storage, communication and visualisation systems to underpin complex data-intensive applications in distinct scientific and technical domains. It is then arguably required to have a seamless interaction of High Performance Computing with Modelling and Simulation in order to store, compute, analyse, and visualise large data sets in science and engineering. Funded by the European Commission, cHiPSet has provided a dynamic trans-European forum for their members and distinguished guests to openly discuss novel perspectives and topics of interests for these two communities. This cHiPSet compendium presents a set of selected case studies related to healthcare, biological data, computational advertising, multimedia, finance, bioinformatics, and telecommunications