Metro Area Network Single Link Failure- Fast Spanning Tree Reconnection

Due to Affordability, ease of maintenance and ubiquity, Ethernet has become a preferred technology to be deployed in to LAN, MAN and WAN networks. Even though Ethernet has being used widely for switched communication it is not meet requirement for Metro Area Networks in terms of network resilience. In this paper, author propose the fast spanning tree re-connection formula, especially for Metro Area Ethernet networks to manage any single link failure, and it has most important feature of fast recovery, backup capacity grantees and ease of fast recovery. If in case of link failure on a spanning tree, a distributed failure recovery protocol is activated to rebuild the broken spanning tree. This is re-connecting the link but not a spanning tree. Author presents the details of the protocol, which including failure notification and forwarding table reconfiguration manual. The Integer linear programming (ILP) is formulated to reconnect-links as it pre-configured. The result of optimization gives the remark of lower implementation cost, fast and effective spanning tree reconnection mechanism can achieve better performance than other resilient technique for Metro Ethernet Network

Survivability schemes for metro ethernet networks

Ph.DDOCTOR OF PHILOSOPH

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

Switches auto-configuráveis

Mestrado em Engenharia Electrónica e TelecomunicaçõesO protocolo Spanning Tree é antigo e completamente desajustado às necessidades das redes Ethernet de hoje em dia. Os seus sucessores, Rapid Spanning Tree Protocol e Multiple Spanning Trees apresentam igualmente problemas de estabilidade e tempos de convergência inadequados. Recentemente foram propostos para standardização, dois novos protocolos que visam a substituição desses protocolos baseados em árvores abrangentes (spanning trees): o TRILL, por parte do IETF, e o SPB, por parte do IEEE. Muito embora sejam idênticos em diversas características, apresentam paradigmas de encaminhamento bastante distintos. O TRILL actua como um protocolo de Layer 3, enquanto que o SPB comporta-se como um típico protocolo de Layer 2. Tanto o TRILL como o SPB adequam-se a grandes redes Ethernet, requerem muito processamento das máquinas e implicam avultados investimentos em novos equipamentos. O protocolo Self-Configurable Switches (SCS) visa substituir os protocolos de spanning tree, alterando radicalmente a filosofia de encaminhamento e controlo de tramas nas redes Ethernet, mas mantendo-se adequado ao segmento dos equipamentos e redes que actualmente correm esses protocolos de spanning tree, minimizando assim potenciais investimentos exagerados. Esta tese apresenta um resumo das funcionalidades e problemas dos actuais protocolos de spanning tree, as principais características dos novos protocolos propostos a standardização e os processos e mecanismos do novo protocolo Self-Configurable Switches (SCS). No final, são apresentados resultados de testes comparativos de funcionalidade, aplicabilidade e performance do protocolo SCS versus os protocolos de spanning tree, que atestam o desempenho superior do protocolo SCS.The Spanning Tree Protocol is old and completely misadjusted towards current Ethernet networks requirements. Its successors, Rapid Spanning Tree Protocol and Multiple Spanning Trees reveal also stability problems and poor convergence times. Recently two new protocols aiming spanning tree protocols substitution were proposed to standard: IETF’s TRILL and IEEE’s SPB. Although similar in many aspects, their forwarding paradigms are quite different. TRILL acts like a Layer 3 protocol, whereas SPB keeps the typical Layer 2 protocol behaviour. Both TRILL and SPB target backbone or core Ethernet networks, requiring great processing power from bridges and huge investment in new gear. Self-Configurable Switches protocol (SCS) objective is to replace the spanning tree protocols, changing radically the frame forwarding and control philosophy over Ethernet networks, but keep being suitable to the range of equipment and networks that tipically run those spanning tree protocols, minimizing potential large investments. This thesis presents an overview of all features and problems of spanning tree protocols, the main characteristics of the new proposal standards and the processes and mechanisms of the new Self-Configurable Switches protocol. At the end, test results are presented regarding features, feasability and performance of SCS protocol versus the spanning tree protocols, which attest SCS protocol superior performance

Optimal Design Strategies for Survivable Carrier Ethernet Networks

Ethernet technologies have evolved through enormous standardization efforts over the past two decades to achieve carrier-grade functionalities, leading to carrier Ethernet. Carrier Ethernet is expected to dominate next generation backbone networks due to its low-cost and simplicity. Ethernet's ability to provide carrier-grade Layer-2 protection switching with SONET/SDH-like fast restoration time is achieved by a new protection switching protocol, Ethernet Ring Protection (ERP). In this thesis, we address two important design aspects of carrier Ethernet networks, namely, survivable design of ERP-based Ethernet transport networks together with energy efficient network design. For the former, we address the problem of optimal resource allocation while designing logical ERP for deployment and model the combinatorially complex problem of joint Ring Protection Link (RPL) placements and ring hierarchies selection as an optimization problem. We develop several Mixed Integer Linear Programming (MILP) model to solve the problem optimally considering both single link failure and concurrent dual link failure scenarios. We also present a traffic engineering based ERP design approach and develop corresponding MILP design models for configuring either single or multiple logical ERP instances over one underlying physical ring. For the latter, we propose two novel architectures of energy efficient Ethernet switches using passive optical correlators for optical bypassing as well as using energy efficient Ethernet (EEE) ports for traffic aggregation and forwarding. We develop an optimal frame scheduling model for EEE ports to ensure minimal energy consumption by using packet coalescing and efficient scheduling

Software Defined Networks based Smart Grid Communication: A Comprehensive Survey

The current power grid is no longer a feasible solution due to ever-increasing user demand of electricity, old infrastructure, and reliability issues and thus require transformation to a better grid a.k.a., smart grid (SG). The key features that distinguish SG from the conventional electrical power grid are its capability to perform two-way communication, demand side management, and real time pricing. Despite all these advantages that SG will bring, there are certain issues which are specific to SG communication system. For instance, network management of current SG systems is complex, time consuming, and done manually. Moreover, SG communication (SGC) system is built on different vendor specific devices and protocols. Therefore, the current SG systems are not protocol independent, thus leading to interoperability issue. Software defined network (SDN) has been proposed to monitor and manage the communication networks globally. This article serves as a comprehensive survey on SDN-based SGC. In this article, we first discuss taxonomy of advantages of SDNbased SGC.We then discuss SDN-based SGC architectures, along with case studies. Our article provides an in-depth discussion on routing schemes for SDN-based SGC. We also provide detailed survey of security and privacy schemes applied to SDN-based SGC. We furthermore present challenges, open issues, and future research directions related to SDN-based SGC.Comment: Accepte

A survey of trends and motivations regarding Communication Service Providers' metro area network implementations

Relevance of research on telecommunications networks is predicated upon the implementations which it explicitly claims or implicitly subsumes. This paper supports researchers through a survey of Communications Service Providers current implementations within the metro area, and trends that are expected to shape the next-generation metro area network. The survey is composed of a quantitative component, complemented by a qualitative component carried out among field experts. Among the several findings, it has been found that service providers with large subscriber base sizes, are less agile in their response to technological change than those with smaller subscriber base sizes: thus, copper media are still an important component in the set of access network technologies. On the other hand, service providers with large subscriber base sizes are strongly committed to deploying distributed access architectures, notably using remote access nodes like remote OLT and remote MAC-PHY. This study also shows that the extent of remote node deployment for multi-access edge computing is about the same as remote node deployment for distributed access architectures, indicating that these two aspects of metro area networks are likely to be co-deployed.Comment: 84 page