24 research outputs found

    Critical ethernet baseada em OpenFlow

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    Mestrado em Engenharia de Computadores e TelemáticaNowadays, we put an immense value on Ethernet networks, especially for data center operations empowering cloud environments or huge network infrastructures in general. However, it is not always possible to bring 100% up-time communications since redundancy in Ethernet has always been an unresolved problem, considering the large amount of network resources to be managed. Through history there have been many developed solutions that tried to solve this issue, only to fail in providing the proper support. Software-defined Networking (SDN) is a novel paradigm and a dynamic and configurable mechanism that brings a programmable nature for developers to implement solutions that may finally solve the identified issues. Via the use of programmable open interfaces, the control and management of network behavior is becoming easier and less error prone. The main objective of this dissertation was the implementation and evaluation of a fail-safe SDN-based solution for critical communications, therefore for fault management in redundant Ethernet technologies on a typical data center management scenario. This dissertation presents the developed solution and the main phases of its implementations. The implemented solution uses a redundant L2 network and a SDN controller to calculate the network topology. The solution makes use of extensions to both the OpenFlow protocol and OpenDaylight controller’s modules. During the evaluation stage, different scenarios were tested where topology changes occur. The evaluation results show that the proposed solution behaves satisfactorily whenever a link fails, obtaining none packet loss. To conclude, the solution shows to be promising for critical data center operations concerning the adaptation time obtained.Hoje em dia coloca-se um valor imenso em redes Ethernet, especialmente para operações em data centers que fornecem serviços na cloud ou em enormes infraestruturas de rede em geral. No entanto, nem sempre é possível existir e garantir comunicações a 100% devido ao facto de a redundância em Ethernet ter sido considerada sempre como um problema não resolvido, tendo em conta a grande quantidade de recursos de rede a serem geridos. Ao longo da história têm sido desenvolvidas diversas soluções que tentaram resolver este problema, apenas para enfrentarem o falhanço em fornecer os requisitos adequados. Software-defined Networking (SDN) é um paradigma inovador e um mecanismo dinâmico e configurável que traz uma natureza programável que permite a implementação de soluções que possam, finalmente, resolver os problemas identificados. Através do uso de interfaces abertas programáveis, o controlo e gestão do comportamento da rede está a tornar-se mais fácil e menos propenso a erros. O objetivo principal desta dissertação foi a implementação e avaliação de uma solução baseada em SDN à prova de falhas para comunicações críticas, portanto para gestão de falhas em tecnologias Ethernet redundantes num cenário típico de gestão de data centers. Esta dissertação apresenta a solução desenvolvida e as principais fases da sua implementação. A solução implementada utiliza uma rede redundante L2 e um controlador SDN para calcular a topologia da rede. A solução faz uso de extensões para o protocolo OpenFlow e módulos do controlador OpenDaylight. Durante a fase de avaliação, diferentes cenários foram testados onde ocorreram mudanças na topologia. Os resultados da avaliação mostram que a solução proposta se comporta de forma satisfatória sempre que uma ligação falha, obtendo perda de pacotes nula. Para concluir, a solução mostra-se promissora para as operações em data centers críticas tendo em conta o tempo de adaptação obtido nas avaliações

    Creating a Worldwide Network For the Global Environment for Network Innovations (GENI) and Related Experimental Environments

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    Many important societal activities are global in scope, and as these activities continually expand world-wide, they are increasingly based on a foundation of advanced communication services and underlying innovative network architecture, technology, and core infrastructure. To continue progress in these areas, research activities cannot be limited to campus labs and small local testbeds or even to national testbeds. Researchers must be able to explore concepts at scale—to conduct experiments on world-wide testbeds that approximate the attributes of the real world. Today, it is possible to take advantage of several macro information technology trends, especially virtualization and capabilities for programming technology resources at a highly granulated level, to design, implement and operate network research environments at a global scale. GENI is developing such an environment, as are research communities in a number of other countries. Recently, these communities have not only been investigating techniques for federating these research environments across multiple domains, but they have also been demonstration prototypes of such federations. This chapter provides an overview of key topics and experimental activities related to GENI international networking and to related projects throughout the world

    A study of the applicability of software-defined networking in industrial networks

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    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

    Review and analysis of networking challenges in cloud computing

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    Cloud Computing offers virtualized computing, storage, and networking resources, over the Internet, to organizations and individual users in a completely dynamic way. These cloud resources are cheaper, easier to manage, and more elastic than sets of local, physical, ones. This encourages customers to outsource their applications and services to the cloud. The migration of both data and applications outside the administrative domain of customers into a shared environment imposes transversal, functional problems across distinct platforms and technologies. This article provides a contemporary discussion of the most relevant functional problems associated with the current evolution of Cloud Computing, mainly from the network perspective. The paper also gives a concise description of Cloud Computing concepts and technologies. It starts with a brief history about cloud computing, tracing its roots. Then, architectural models of cloud services are described, and the most relevant products for Cloud Computing are briefly discussed along with a comprehensive literature review. The paper highlights and analyzes the most pertinent and practical network issues of relevance to the provision of high-assurance cloud services through the Internet, including security. Finally, trends and future research directions are also presented

    All-Path Bridging: Path Exploration Protocols for Data Center and Campus Networks

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    Today, link-state routing protocols that compute multiple shortest paths predominate in data center and campus networks, where routing is performed either in layer three or in layer two using link-state routing protocols. But current proposals based on link-state routing do not adapt well to real time traffic variations and become very complex when attempting to balance the traffic load. We propose All-Path bridging, an evolution of the classical transparent bridging that forwards frames over shortest paths using the complete network topology, which overcomes the limitations of the spanning tree protocol. All-Path is a new frame routing paradigm based on the simultaneous exploration of all paths of the real network by a broadcast probe frame, instead of computing routes on the network graph. This paper presents All- Path switches and their differences with standard switches and describes ARP-Path protocol in detail, its path recovery mechanisms and compatibility with IEEE 802.1 standard bridges. ARP-Path is the first protocol variant of the All-Path protocol family. ARP-Path reuses the standard ARP Request and Reply packets to explore reactively the network and find the fastest path between two hosts. We compare its performance in terms of latency and load distribution with link-state shortest-path routing bridges, showing that ARP-Path distributes the load more evenly and provides lower latencies. Implementations on different platforms prove the robustness of the protocol. The conclusion is that All-Path bridging offer a simple, resilient and scalable alternative to path computation protocols

    All-Path Bridging: Path Exploration Protocols for Data Center and Campus Networks

    Get PDF
    Today, link-state routing protocols that compute multiple shortest paths predominate in data center and campus networks, where routing is performed either in layer three or in layer two using link-state routing protocols. But current proposals based on link-state routing do not adapt well to real time traffic variations and become very complex when attempting to balance the traffic load. We propose All-Path bridging, an evolution of the classical transparent bridging that forwards frames over shortest paths using the complete network topology, which overcomes the limitations of the spanning tree protocol. All-Path is a new frame routing paradigm based on the simultaneous exploration of all paths of the real network by a broadcast probe frame, instead of computing routes on the network graph. This paper presents All- Path switches and their differences with standard switches and describes ARP-Path protocol in detail, its path recovery mechanisms and compatibility with IEEE 802.1 standard bridges. ARP-Path is the first protocol variant of the All-Path protocol family. ARP-Path reuses the standard ARP Request and Reply packets to explore reactively the network and find the fastest path between two hosts. We compare its performance in terms of latency and load distribution with link-state shortest-path routing bridges, showing that ARP-Path distributes the load more evenly and provides lower latencies. Implementations on different platforms prove the robustness of the protocol. The conclusion is that All-Path bridging offer a simple, resilient and scalable alternative to path computation protocols
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