4 research outputs found

    A novel predictive PCE-based protection strategy for resilient transport networks

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    漏 2016. The ever increasing requirements of new Internet applications are pushing to optimize the design of optical networks. A key design criterion in network design is the ability to recover from failures in an agile and efficient manner. Protection capabilities are highly required in optical networks since the failure of an optical link might potentially lead to a significant traffic loss. Under this context, Network Coding Protection (NCP) has emerged as an innovative solution to proactively enable protection in an agile and efficient manner by means of throughput improvement techniques such as Network Coding (NC). Nevertheless, the benefits of NC can be reduced by the negative effects of inaccurate Network State Information (NSI), which are common in dynamic scenarios.In this paper, we propose a novel proactive protection strategy based on NC jointly with a Path Computation Element (PCE) architecture called Predictive Network Coding Protection (PNCP). PNCP leverages predictive techniques in order to mitigate the negative impact of the inaccurate NSI on the blocking probability. In addition, PNCP computes resilient lightpaths with a low amount of network resources devoted for path protection.By means of extensive simulation results we show that in comparison with proactive protection strategies such as Dedicated Path Protection (DPP), and conventional dynamic NCP, PNCP reduces the blocking probability as well as the network resources allocated for path protection in dynamic scenarios.Postprint (author's final draft

    An ontology-based approach toward the configuration of heterogeneous network devices

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    Despite the numerous efforts of standardization, semantic issues remain in effect in many subfields of networking. The inability to exchange data unambiguously between information systems and human resources is an issue that hinders technology implementation, semantic interoperability, service deployment, network management, technology migration, among many others. In this thesis, we will approach the semantic issues in two critical subfields of networking, namely, network configuration management and network addressing architectures. The fact that makes the study in these areas rather appealing is that in both scenarios semantic issues have been around from the very early days of networking. However, as networks continue to grow in size and complexity current practices are becoming neither scalable nor practical. One of the most complex and essential tasks in network management is the configuration of network devices. The lack of comprehensive and standard means for modifying and controlling the configuration of network elements has led to the continuous and extended use of proprietary Command Line Interfaces (CLIs). Unfortunately, CLIs are generally both, device and vendor-specific. In the context of heterogeneous network infrastructures---i.e., networks typically composed of multiple devices from different vendors---the use of several CLIs raises serious Operation, Administration and Management (OAM) issues. Accordingly, network administrators are forced to gain specialized expertise and to continuously keep knowledge and skills up to date as new features, system upgrades or technologies appear. Overall, the utilization of proprietary mechanisms allows neither sharing knowledge consistently between vendors' domains nor reusing configurations to achieve full automation of network configuration tasks---which are typically required in autonomic management. Due to this heterogeneity, CLIs typically provide a help feature which is in turn an useful source of knowledge to enable semantic interpretation of a vendor's configuration space. The large amount of information a network administrator must learn and manage makes Information Extraction (IE) and other forms of natural language analysis of the Artificial Intelligence (AI) field key enablers for the network device configuration space. This thesis presents the design and implementation specification of the first Ontology-Based Information Extraction (OBIE) System from the CLI of network devices for the automation and abstraction of device configurations. Moreover, the so-called semantic overload of IP addresses---wherein addresses are both identifiers and locators of a node at the same time---is one of the main constraints over mobility of network hosts, multi-homing and scalability of the routing system. In light of this, numerous approaches have emerged in an effort to decouple the semantics of the network addressing scheme. In this thesis, we approach this issue from two perspectives, namely, a non-disruptive (i.e., evolutionary) solution to the current Internet and a clean-slate approach for Future Internet. In the first scenario, we analyze the Locator/Identifier Separation Protocol (LISP) as it is currently one of the strongest solutions to the semantic overload issue. However, its adoption is hindered by existing problems in the proposed mapping systems. Herein, we propose the LISP Redundancy Protocol (LRP) aimed to complement the LISP framework and strengthen feasibility of deployment, while at the same time, minimize mapping table size, latency time and maximize reachability in the network. In the second scenario, we explore TARIFA a Next Generation Internet architecture and introduce a novel service-centric addressing scheme which aims to overcome the issues related to routing and semantic overload of IP addresses.A pesar de los numerosos esfuerzos de estandarizaci贸n, los problemas de sem谩ntica contin煤an en efecto en muchas sub谩reas de networking. La inabilidad de intercambiar data sin ambiguedad entre sistemas es un problema que limita la interoperabilidad sem谩ntica. En esta tesis, abordamos los problemas de sem谩ntica en dos 谩reas: (i) la gesti贸n de configuraci贸n y (ii) arquitecturas de direccionamiento. El hecho que hace el estudio en estas 谩reas de inter茅s, es que los problemas de sem谩ntica datan desde los inicios del Internet. Sin embargo, mientras las redes contin煤an creciendo en tama帽o y complejidad, los mecanismos desplegados dejan de ser escalabales y pr谩cticos. Una de las tareas m谩s complejas y esenciales en la gesti贸n de redes es la configuraci贸n de equipos. La falta de mecanismos est谩ndar para la modificaci贸n y control de la configuraci贸n de equipos ha llevado al uso continuado y extendido de interfaces por l铆neas de comando (CLI). Desafortunadamente, las CLIs son generalmente, espec铆ficos por fabricante y dispositivo. En el contexto de redes heterog茅neas--es decir, redes t铆picamente compuestas por m煤ltiples dispositivos de distintos fabricantes--el uso de varias CLIs trae consigo serios problemas de operaci贸n, administraci贸n y gesti贸n. En consecuencia, los administradores de red se ven forzados a adquirir experiencia en el manejo espec铆fico de m煤ltiples tecnolog铆as y adem谩s, a mantenerse continuamente actualizados en la medida en que nuevas funcionalidades o tecnolog铆as emergen, o bien con actualizaciones de sistemas operativos. En general, la utilizaci贸n de mecanismos propietarios no permite compartir conocimientos de forma consistente a lo largo de plataformas heterog茅neas, ni reutilizar configuraciones con el objetivo de alcanzar la completa automatizaci贸n de tareas de configuraci贸n--que son t铆picamente requeridas en el 谩rea de gesti贸n auton贸mica. Debido a esta heterogeneidad, las CLIs suelen proporcionar una funci贸n de ayuda que fundamentalmente aporta informaci贸n para la interpretaci贸n sem谩ntica del entorno de configuraci贸n de un fabricante. La gran cantidad de informaci贸n que un administrador debe aprender y manejar, hace de la extracci贸n de informaci贸n y otras formas de an谩lisis de lenguaje natural del campo de Inteligencia Artificial, potenciales herramientas para la configuraci贸n de equipos en entornos heterog茅neos. Esta tesis presenta el dise帽o y especificaciones de implementaci贸n del primer sistema de extracci贸n de informaci贸n basada en ontolog铆as desde el CLI de dispositivos de red, para la automatizaci贸n y abstracci贸n de configuraciones. Por otra parte, la denominada sobrecarga sem谩ntica de direcciones IP--en donde, las direcciones son identificadores y localizadores al mismo tiempo--es una de las principales limitaciones sobre mobilidad, multi-homing y escalabilidad del sistema de enrutamiento. Por esta raz贸n, numerosas propuestas han emergido en un esfuerzo por desacoplar la sem谩ntica del esquema de direccionamiento de las redes actuales. En esta tesis, abordamos este problema desde dos perspectivas, la primera de ellas una aproximaci贸n no-disruptiva (es decir, evolucionaria) al problema del Internet actual y la segunda, una nueva propuesta en torno a futuras arquitecturas del Internet. En el primer escenario, analizamos el protocolo LISP (del ingl茅s, Locator/Identifier Separation Protocol) ya que es en efecto, una de las soluciones con mayor potencial para la resolucion del problema de sem谩ntica. Sin embargo, su adopci贸n est谩 limitada por problemas en los sistemas de mapeo propuestos. En esta tesis, proponemos LRP (del ingl茅s, LISP Redundancy Protocol) un protocolo destinado a complementar LISP e incrementar la factibilidad de despliegue, a la vez que, reduce el tama帽o de las tablas de mapeo, tiempo de latencia y maximiza accesibilidad. En el segundo escenario, exploramos TARIFA una arquitectura de red de nueva generaci贸n e introducimos un novedoso esquema de direccionamiento orientado a servicios

    Resilience mechanisms for carrier-grade networks

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    In recent years, the advent of new Future Internet (FI) applications is creating ever-demanding requirements. These requirements are pushing network carriers for high transport capacity, energy efficiency, as well as high-availability services with low latency. A widespread practice to provide FI services is the adoption of a multi-layer network model consisting in the use of IP/MPLS and optical technologies such as Wavelength Division Multiplexing (WDM). Indeed, optical transport technologies are the foundation supporting the current telecommunication network backbones, because of the high transmission bandwidth achieved in fiber optical networks. Traditional optical networks consist of a fixed 50 GHz grid, resulting in a low Optical Spectrum (OS) utilization, specifically with transmission rates above 100 Gbps. Recently, optical networks have been undergoing significant changes with the purpose of providing a flexible grid that can fully exploit the potential of optical networks. This has led to a new network paradigm termed as Elastic Optical Network (EON). In recent years, the advent of new Future Internet (FI) applications is creating ever-demanding requirements. A widespread practice to provide FI services is the adoption of a multi-layer network model consisting in the use of IP/MPLS and optical technologies such as Wavelength Division Multiplexing (WDM). Traditional optical networks consist of a fixed 50 GHz grid, resulting in a low Optical Spectrum (OS) utilization. Recently, optical networks have been undergoing significant changes with the purpose of providing a flexible grid that can fully exploit the potential of optical networks. This has led to a new network paradigm termed as Elastic Optical Network (EON). Recently, a new protection scheme referred to as Network Coding Protection (NCP) has emerged as an innovative solution to proactively enable protection in an agile and efficient manner by means of throughput improvement techniques such as Network Coding. It is an intuitive reasoning that the throughput advantages of NCP might be magnified by means of the flexible-grid provided by EONs. The goal of this thesis is three-fold. The first, is to study the advantages of NCP schemes in planning scenarios. For this purpose, this thesis focuses on the performance of NCP assuming both a fixed as well as a flexible spectrum grid. However, conversely to planning scenarios, in dynamic scenarios the accuracy of Network State Information (NSI) is crucial since inaccurate NSI might substantially affect the performance of an NCP scheme. The second contribution of this thesis is to study the performance of protection schemes in dynamic scenarios considering inaccurate NSI. For this purpose, this thesis explores prediction techniques in order to mitigate the negative effects of inaccurate NSI. On the other hand, Internet users are continuously demanding new requirements that cannot be supported by the current host-oriented communication model.This communication model is not suitable for future Internet architectures such as the so-called Internet of Things (IoT). Fortunately, there is a new trend in network research referred to as ID/Locator Split Architectures (ILSAs) which is a non-disruptive technique to mitigate the issues related to host-oriented communications. Moreover, a new routing architecture referred to as Path Computation Element (PCE) has emerged with the aim of overcoming the well-known issues of the current routing schemes. Undoubtedly, routing and protection schemes need to be enhanced to fully exploit the advantages provided by new network architectures.In light of this, the third goal of this thesis introduces a novel PCE-like architecture termed as Context-Aware PCE. In a context-aware PCE scenario, the driver of a path computation is not a host/location, as in conventional PCE architectures, rather it is an interest for a service defined within a context.En los 煤ltimos a帽os la llegada de nuevas aplicaciones del llamado Internet del Futuro (FI) est谩 creando requerimientos sumamente exigentes. Estos requerimientos est谩n empujando a los proveedores de redes a incrementar sus capacidades de transporte, eficiencia energ茅tica, y sus prestaciones de servicios de alta disponibilidad con baja latencia. Es una pr谩ctica sumamente extendida para proveer servicios (FI) la adopci贸n de un modelo multi-capa el cual consiste en el uso de tecnolog铆as IP/MPLS as铆 como tambi茅n 贸pticas como por ejemplo Wavelength Division Multiplexing (WDM). De hecho, las tecnolog铆as de transporte son el sustento del backbone de las redes de telecomunicaciones actuales debido al gran ancho de banda que proveen las redes de fibra 贸ptica. Las redes 贸pticas tradicionales consisten en el uso de un espectro fijo de 50 GHz. Esto resulta en una baja utilizaci贸n del espectro 脫ptico, espec铆ficamente con tasas de transmisiones superiores a 100 Gbps. Recientemente, las redes 贸pticas est谩n experimentado cambios significativos con el prop贸sito de proveer un espectro flexible que pueda explotar el potencial de las redes 贸pticas. Esto ha llevado a un nuevo paradigma denominado Redes 脫pticas El谩sticas (EON). Por otro lado, un nuevo esquema de protecci贸n llamado Network Coding Protection (NCP) ha emergido como una soluci贸n innovadora para habilitar de manera proactiva protecci贸n eficiente y 谩gil usando t茅cnicas de mejora de throughput como es Network Coding (NC). Es un razonamiento l贸gico pensar que las ventajas relacionadas con throughput de NCP pueden ser magnificadas mediante el espectro flexible prove铆do por las redes EONs. El objetivo de esta tesis es triple. El primero es estudiar las ventajas de esquemas NCP en un escenario de planificaci贸n. Para este prop贸sito, esta tesis se enfoca en el rendimiento de NCP asumiendo un espectro fijo y un espectro flexible. Sin embargo, contrario a escenarios de planificaci贸n, en escenarios din谩micos la precisi贸n relacionada de la Informaci贸n de Estado de Red (NSI) es crucial, ya que la imprecisi贸n de NSI puede afectar sustancialmente el rendimiento de un esquema NCP. La segunda contribuci贸n de esta tesis es el estudio del rendimiento de esquemas de protecci贸n en escenarios din谩micos considerando NSI no precisa. Para este prop贸sito, esta tesis explora t茅cnicas predictivas con el prop贸sito de mitigar los efectos negativos de NSI impreciso. Por otro lado, los usuarios de Internet est谩n demandando continuamente nuevos requerimientos los cuales no pueden ser soportados por el modelo de comunicaci贸n orientado a hosts. Este modelo de comunicaciones no es factible para arquitecturas FI como es el Internet de las cosas (IoT). Afortunadamente, existe un nueva l铆nea investigativa llamada ID/Locator Split Architectures (ILSAs) la cual es una t茅cnica no disruptiva para mitigar los problemas relacionadas con el modelo de comunicaci贸n orientado a hosts. Adem谩s, un nuevo esquema de enrutamiento llamado as Path Computation Element (PCE) ha emergido con el prop贸sito de superar los problemas bien conocidos de los esquemas de enrutamiento tradicionales. Indudablemente, los esquemas de enrutamiento y protecci贸n deben ser mejorados para que estos puedan explotar las ventajas introducidas por las nuevas arquitecturas de redes. A luz de esto, el tercer objetivo de esta tesis es introducir una nueva arquitectura PCE denominada Context-Aware PCE. En un escenario context-aware PCE, el objetivo de una acci贸n de computaci贸n de camino no es un host o localidad, como es el caso en lo esquemas PCE tradicionales. M谩s bien, es un inter茅s por un servicio definido dentro de una informaci贸n de contexto

    Network coding-based protection scheme for elastic optical networks

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    Optical technologies are the foundations supporting the current telecommunication network backbones due to the high speed transmissions achieved in fiber optical networks. Traditional optical networks consist of a fixed 50 GHz grid, resulting in a low optical spectrum (OS) utilization, specifically with transmission rates above 100 Gbps. This issue is magnified when network resilience capabilities are required. For instance, proactive protection solutions such as Dedicated Protection (DP) are widely used because of their low recovery time. However, a significant drawback of DP is its high utilization of optical bandwidth. Recently, optical networks are undergoing significant changes with the purpose of providing a flexible grid that can fully exploit the potential of optical networks. This has led to a new network paradigm termed as Elastic Optical Networks (EON). Moreover, a novel strategy referred to as network coding (NC) has been proposed with the aim of improving network throughput. In this paper, we propose a proactive protection scheme so-called E-DPNC that combines both the advantages concerning network throughput offered by EON and NC, and the low recovery time of a DP scheme, in order to enable network resilience against optical link failures while also reducing the optical spectrum utilization. Our evaluation results show that our solution reduces the OS utilization by 41% compared with conventional protection schemes deployed on fixed grid scenarios
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