Space station data system analysis/architecture study. Task 2: Options development, DR-5. Volume 2: Design options

The primary objective of Task 2 is the development of an information base that will support the conduct of trade studies and provide sufficient data to make key design/programmatic decisions. This includes: (1) the establishment of option categories that are most likely to influence Space Station Data System (SSDS) definition; (2) the identification of preferred options in each category; and (3) the characterization of these options with respect to performance attributes, constraints, cost and risk. This volume contains the options development for the design category. This category comprises alternative structures, configurations and techniques that can be used to develop designs that are responsive to the SSDS requirements. The specific areas discussed are software, including data base management and distributed operating systems; system architecture, including fault tolerance and system growth/automation/autonomy and system interfaces; time management; and system security/privacy. Also discussed are space communications and local area networking

Enhanced connectivity in wireless mobile programmable networks

Mención Interancional en el título de doctorThe architecture of current operator infrastructures is being challenged by the non-stop growing demand of data hungry services appearing every day. While currently deployed operator networks have been able to cope with traffic demands so far, the architectures for the 5th generation of mobile networks (5G) are expected to support unprecedented traffic loads while decreasing costs associated with the network deployment and operations. Indeed, the forthcoming set of 5G standards will bring programmability and flexibility to levels never seen before. This has required introducing changes in the architecture of mobile networks, enabling different features such as the split of control and data planes, as required to support rapid programming of heterogeneous data planes. Network softwarisation is hence seen as a key enabler to cope with such network evolution, as it permits controlling all networking functions through (re)programming, thus providing higher flexibility to meet heterogeneous requirements while keeping deployment and operational costs low. A great diversity in terms of traffic patterns, multi-tenancy, heterogeneous and stringent traffic requirements is therefore expected in 5G networks. Software Defined Networking (SDN) and Network Function Virtualisation (NFV) have emerged as a basic tool-set for operators to manage their infrastructure with increased flexibility and reduced costs. As a result, new 5G services can now be envisioned and quickly programmed and provisioned in response to user and market necessities, imposing a paradigm shift in the services design. However, such flexibility requires the 5G transport network to undergo a profound transformation, evolving from a static connectivity substrate into a service-oriented infrastructure capable of accommodating the various 5G services, including Ultra-Reliable and Low Latency Communications (URLLC). Moreover, to achieve the desired flexibility and cost reduction, one promising approach is to leverage virtualisation technologies to dynamically host contents, services, and applications closer to the users so as to offload the core network and reduce the communication delay. This thesis tackles the above challengeswhicharedetailedinthefollowing. A common characteristic of the 5G servicesistheubiquityandthealmostpermanent connection that is required from the mobile network. This really imposes a challenge in thesignallingproceduresprovidedtogettrack of the users and to guarantee session continuity. The mobility management mechanisms will hence play a central role in the 5G networks because of the always-on connectivity demand. Distributed Mobility Management (DMM) helps going towards this direction, by flattening the network, hence improving its scalability,andenablinglocalaccesstotheInternet and other communication services, like mobile-edge clouds. Simultaneously, SDN opens up the possibility of running a multitude of intelligent and advanced applications for network optimisation purposes in a centralised network controller. The combination of DMM architectural principles with SDN management appears as a powerful tool for operators to cope with the management and data burden expected in 5G networks. To meet the future mobile user demand at a reduced cost, operators are also looking at solutions such as C-RAN and different functional splits to decrease the cost of deploying and maintaining cell sites. The increasing stress on mobile radio access performance in a context of declining revenues for operators is hence requiring the evolution of backhaul and fronthaul transport networks, which currently work decoupled. The heterogeneity of the nodes and transmisión technologies inter-connecting the fronthaul and backhaul segments makes the network quite complex, costly and inefficient to manage flexibly and dynamically. Indeed, the use of heterogeneous technologies forces operators to manage two physically separated networks, one for backhaul and one forfronthaul. In order to meet 5G requirements in a costeffective manner, a unified 5G transport network that unifies the data, control, and management planes is hence required. Such an integrated fronthaul/backhaul transport network, denoted as crosshaul, will hence carry both fronthaul and backhaul traffic operating over heterogeneous data plane technologies, which are software-controlled so as to adapt to the fluctuating capacity demand of the 5G air interfaces. Moreover, 5G transport networks will need to accommodate a wide spectrum of services on top of the same physical infrastructure. To that end, network slicing is seen as a suitable candidate for providing the necessary Quality of Service (QoS). Traffic differentiation is usually enforced at the border of the network in order to ensure a proper forwarding of the traffic according to its class through the backbone. With network slicing, the traffic may now traverse many slice edges where the traffic policy needs to be enforced, discriminated and ensured, according to the service and tenants needs. However, the very basic nature that makes this efficient management and operation possible in a flexible way – the logical centralisation – poses important challenges due to the lack of proper monitoring tools, suited for SDN-based architectures. In order to take timely and right decisions while operating a network, centralised intelligence applications need to be fed with a continuous stream of up-to-date network statistics. However, this is not feasible with current SDN solutions due to scalability and accuracy issues. Therefore, an adaptive telemetry system is required so as to support the diversity of 5G services and their stringent traffic requirements. The path towards 5G wireless networks alsopresentsacleartrendofcarryingoutcomputations close to end users. Indeed, pushing contents, applications, and network functios closer to end users is necessary to cope with thehugedatavolumeandlowlatencyrequired in future 5G networks. Edge and fog frameworks have emerged recently to address this challenge. Whilst the edge framework was more infrastructure-focused and more mobile operator-oriented, the fog was more pervasive and included any node (stationary or mobile), including terminal devices. By further utilising pervasive computational resources in proximity to users, edge and fog can be merged to construct a computing platform, which can also be used as a common stage for multiple radio access technologies (RATs) to share their information, hence opening a new dimension of multi-RAT integration.La arquitectura de las infraestructuras actuales de los operadores está siendo desafiada por la demanda creciente e incesante de servicios con un elevado consumo de datos que aparecen todos los días. Mientras que las redes de operadores implementadas actualmente han sido capaces de lidiar con las demandas de tráfico hasta ahora, se espera que las arquitecturas de la quinta generación de redes móviles (5G) soporten cargas de tráfico sin precedentes a la vez que disminuyen los costes asociados a la implementación y operaciones de la red. De hecho, el próximo conjunto de estándares 5G traerá la programabilidad y flexibilidad a niveles nunca antes vistos. Esto ha requerido la introducción de cambios en la arquitectura de las redes móviles, lo que permite diferentes funciones, como la división de los planos de control y de datos, según sea necesario para soportar una programación rápida de planos de datos heterogéneos. La softwarisación de red se considera una herramienta clave para hacer frente a dicha evolución de red, ya que proporciona la capacidad de controlar todas las funciones de red mediante (re)programación, proporcionando así una mayor flexibilidad para cumplir requisitos heterogéneos mientras se mantienen bajos los costes operativos y de implementación. Por lo tanto, se espera una gran diversidad en términos de patrones de tráfico, multi-tenancy, requisitos de tráfico heterogéneos y estrictos en las redes 5G. Software Defined Networking (SDN) y Network Function Virtualisation (NFV) se han convertido en un conjunto de herramientas básicas para que los operadores administren su infraestructura con mayor flexibilidad y menores costes. Como resultado, los nuevos servicios 5G ahora pueden planificarse, programarse y aprovisionarse rápidamente en respuesta a las necesidades de los usuarios y del mercado, imponiendo un cambio de paradigma en el diseño de los servicios. Sin embargo, dicha flexibilidad requiere que la red de transporte 5G experimente una transformación profunda, que evoluciona de un sustrato de conectividad estática a una infraestructura orientada a servicios capaz de acomodar los diversos servicios 5G, incluso Ultra-Reliable and Low Latency Communications (URLLC). Además, para lograr la flexibilidad y la reducción de costes deseadas, un enfoque prometedores aprovechar las tecnologías de virtualización para alojar dinámicamente los contenidos, servicios y aplicaciones más cerca de los usuarios para descargar la red central y reducir la latencia. Esta tesis aborda los desafíos anteriores que se detallan a continuación. Una característica común de los servicios 5G es la ubicuidad y la conexión casi permanente que se requiere para la red móvil. Esto impone un desafío en los procedimientos de señalización proporcionados para hacer un seguimiento de los usuarios y garantizar la continuidad de la sesión. Por lo tanto, los mecanismos de gestión de la movilidad desempeñarán un papel central en las redes 5G debido a la demanda de conectividad siempre activa. Distributed Mobility Management (DMM) ayuda a ir en esta dirección, al aplanar la red, lo que mejora su escalabilidad y permite el acceso local a Internet y a otros servicios de comunicaciones, como recursos en “nubes” situadas en el borde de la red móvil. Al mismo tiempo, SDN abre la posibilidad de ejecutar una multitud de aplicaciones inteligentes y avanzadas para optimizar la red en un controlador de red centralizado. La combinación de los principios arquitectónicos DMM con SDN aparece como una poderosa herramienta para que los operadores puedan hacer frente a la carga de administración y datos que se espera en las redes 5G. Para satisfacer la demanda futura de usuarios móviles a un coste reducido, los operadores también están buscando soluciones tales como C-RAN y diferentes divisiones funcionales para disminuir el coste de implementación y mantenimiento de emplazamientos celulares. El creciente estrés en el rendimiento del acceso a la radio móvil en un contexto de menores ingresos para los operadores requiere, por lo tanto, la evolución de las redes de transporte de backhaul y fronthaul, que actualmente funcionan disociadas. La heterogeneidad de los nodos y las tecnologías de transmisión que interconectan los segmentos de fronthaul y backhaul hacen que la red sea bastante compleja, costosa e ineficiente para gestionar de manera flexible y dinámica. De hecho, el uso de tecnologías heterogéneas obliga a los operadores a gestionar dos redes separadas físicamente, una para la red de backhaul y otra para el fronthaul. Para cumplir con los requisitos de 5G de manera rentable, se requiere una red de transporte única 5G que unifique los planos de control, datos y de gestión. Dicha red de transporte fronthaul/backhaul integrada, denominada “crosshaul”, transportará tráfico de fronthaul y backhaul operando sobre tecnologías heterogéneas de plano de datos, que están controladas por software para adaptarse a la demanda de capacidad fluctuante de las interfaces radio 5G. Además, las redes de transporte 5G necesitarán acomodar un amplio espectro de servicios sobre la misma infraestructura física y el network slicing se considera un candidato adecuado para proporcionar la calidad de servicio necesario. La diferenciación del tráfico generalmente se aplica en el borde de la red para garantizar un reenvío adecuado del tráfico según su clase a través de la red troncal. Con el networkslicing, el tráfico ahora puede atravesar muchos fronteras entre “network slices” donde la política de tráfico debe aplicarse, discriminarse y garantizarse, de acuerdo con las necesidades del servicio y de los usuarios. Sin embargo, el principio básico que hace posible esta gestión y operación eficientes de forma flexible – la centralización lógica – plantea importantes desafíos debido a la falta de herramientas de supervisión necesarias para las arquitecturas basadas en SDN. Para tomar decisiones oportunas y correctas mientras se opera una red, las aplicaciones de inteligencia centralizada necesitan alimentarse con un flujo continuo de estadísticas de red actualizadas. Sin embargo, esto no es factible con las soluciones SDN actuales debido a problemas de escalabilidad y falta de precisión. Por lo tanto, se requiere un sistema de telemetría adaptable para respaldar la diversidad de los servicios 5G y sus estrictos requisitos de tráfico. El camino hacia las redes inalámbricas 5G también presenta una tendencia clara de realizar acciones cerca de los usuarios finales. De hecho, acercar los contenidos, las aplicaciones y las funciones de red a los usuarios finales es necesario para hacer frente al enorme volumen de datos y la baja latencia requerida en las futuras redes 5G. Los paradigmas de “edge” y “fog” han surgido recientemente para abordar este desafío. Mientras que el edge está más centrado en la infraestructura y más orientado al operador móvil, el fog es más ubicuo e incluye cualquier nodo (fijo o móvil), incluidos los dispositivos finales. Al utilizar recursos de computación de propósito general en las proximidades de los usuarios, el edge y el fog pueden combinarse para construir una plataforma de computación, que también se puede utilizar para compartir información entre múltiples tecnologías de acceso radio (RAT) y, por lo tanto, abre una nueva dimensión de la integración multi-RAT.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Carla Fabiana Chiasserini.- Secretario: Vincenzo Mancuso.- Vocal: Diego Rafael López Garcí

ADAM : a decentralized parallel computer architecture featuring fast thread and data migration and a uniform hardware abstraction

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 247-256).The furious pace of Moore's Law is driving computer architecture into a realm where the the speed of light is the dominant factor in system latencies. The number of clock cycles to span a chip are increasing, while the number of bits that can be accessed within a clock cycle is decreasing. Hence, it is becoming more difficult to hide latency. One alternative solution is to reduce latency by migrating threads and data, but the overhead of existing implementations has previously made migration an unserviceable solution so far. I present an architecture, implementation, and mechanisms that reduces the overhead of migration to the point where migration is a viable supplement to other latency hiding mechanisms, such as multithreading. The architecture is abstract, and presents programmers with a simple, uniform fine-grained multithreaded parallel programming model with implicit memory management. In other words, the spatial nature and implementation details (such as the number of processors) of a parallel machine are entirely hidden from the programmer. Compiler writers are encouraged to devise programming languages for the machine that guide a programmer to express their ideas in terms of objects, since objects exhibit an inherent physical locality of data and code. The machine implementation can then leverage this locality to automatically distribute data and threads across the physical machine by using a set of high performance migration mechanisms.(cont.) An implementation of this architecture could migrate a null thread in 66 cycles - over a factor of 1000 improvement over previous work. Performance also scales well; the time required to move a typical thread is only 4 to 5 times that of a null thread. Data migration performance is similar, and scales linearly with data block size. Since the performance of the migration mechanism is on par with that of an L2 cache, the implementation simulated in my work has no data caches and relies instead on multithreading and the migration mechanism to hide and reduce access latencies.by Andrew "bunnie" Huang.Ph.D

Open Platforms for Connected Vehicles

L'abstract è presente nell'allegato / the abstract is in the attachmen

Contributions towards softwarization and energy saving in passive optical networks

Ths thesis is a result of contributions to optimize and improve the network management systme and power consumption in Passive Optical Network (PON). Passive Optical Network elements such as Optical Line Terminal (OLT) and Optical Network Units (ONUs) are currently managed by inflexible legacy network management systems. Software-Defined Networking (SDN) is a new networking paradigm that improves the operation and management of networks by decoupling control plane from data plane. Currently, network management in PON networks is not always automated nor normalized. One goal of the researchers in optical networking is to improve the programmability, efficiency, and global optimization of network operations, in order to minimize both Capital Expenditure (CAPEX) and Operational Expenditure (OPEX) by reducing the complexity of devices and its operation. Therefore, it makes sense to use an SDN approach in order to manage the passive optical network functionalities and migrating must of the upper layer functions to the SDN controller. Many approaches have already addressed the topic of applying the SDN architecture in PON networks. However; the focus was usually on facilitating the deployment of SDN-based service and so Service Interoperability remains unexplored in detail. The main challenge toward this goal is how to make compatible the synchronous nature of the EPON media access control protocols with the asynchronous architecture of SDN, and in particular, OpenFlow. In our proposed architecture, the OLT is partially virtualized and some of its functionalities are allocated to the core network management system, while the OLT itself is replaced by an OpenFlow switch. A new MultiPoint MAC Control (MPMC) sublayer extension based on the OpenFlow protocol is presented. The OpenFlow switch is extended with synchronous ports to retain the time-critical nature of the EPON network. Our simulation-based results demonstrate the effectiveness of the new architecture, while retaining a similar (or improved) performance in term of delay and throughput when compared to legacy PONs. Nowadays, many researchers are working simultaneously to develop power saving techniques and improves energy efficiency in the PON network, and since the contribution of access networks to the global energy consumption is large, energy efficiency has become an increasingly important requirement in designing access networks. Therefore, energy-saving approaches are being investigated to provide high performance and consume less energy. Several techniques have been proposed to increase energy efficiency in PON networks. Such techniques are related to the centeralized DBA but the advantage of power saving in a distributed DBA remains untouched. We present a distributed energy-efficient Dynamic Bandwidth Allocation (DBA) algorithm for both the upstream and downstream channels of EPON to improve energy efficiency in EPON networks. The proposed algorithm analyzes the queue status of the ONUs and OLT in order to power-off the transmitter and/or receiver of an ONU whenever there is no upstream or downstream traffic. We have been able to combine the advantage of a distributed DBA such as DDSPON (a smaller packet delay, due to the shorter time needed by DDSPON to allocate the transmission slots) and the energy-saving features (that come at a price of longer packet delays due to the fact that switching off the transmitters make the packet queues grow). Our proposed DBA algorithm minimizes the ONU energy consumption across a wide range of network loads, while maintaining at an acceptable level the penalty introduced in terms of channel utilization and packet delay.Las contribuciones de esta tesis se centran en mejorar el sistema de gestión de red y el consumo de energía en redes de acceso ópticas pasivas (PON). Los elementos de las redes PON, como el terminal de línea óptica (OLT) y las unidades de red ópticas (ONU), se gestionan actualmente mediante sistemas poco flexibles. El nuevo paradigma de redes definidas por software (SDN) mejora la gestión de redes al desacoplar el plano de control del plano de datos. Actualmente, la gestión de redes PON no está automatizada ni normalizada. Uno de los objetivos de los investigadores en redes ópticas es mejorar la programabilidad, la eficiencia y la optimización global de las operaciones de red, con el fin de minimizar tanto el gasto de capital (CAPEX) como el gasto operativo (OPEX) al reducir la complejidad de los dispositivos y su funcionamiento. Por lo tanto, tiene sentido utilizar un enfoque SDN para gestionar las funciones de red óptica pasiva y migrar algunas de las funciones PON de capas superiores al controlador SDN. Otros investigadores han estudiado esta aproximación. sin embargo; el enfoque generalmente estaba en facilitar la implementación del servicio basado en SDN y, por lo tanto, la interoperabilidad de los servicios permanecía sin ser explorado en detalle. El principal desafío hacia este objetivo es cómo compatibilizar la naturaleza síncrona de los protocolos de control de acceso a medios EPON con la arquitectura asíncrona de SDN y, en particular, OpenFlow. En nuestra propuesta de arquitectura, la OLT se virtualiza parcialmente y algunas de sus funcionalidades se asignan al sistema de gestión de red centralizado, mientras que la OLT se reemplaza por un conmutador OpenFlow. Proponemos una nueva extensión de la subcapa de control múltiple de MAC (MPMC) basada en el protocolo OpenFlow. El conmutador OpenFlow se amplía con puertos síncronos para asegurar la naturaleza de tiempo real de la red EPON. Nuestros resultados basados ¿¿en simulaciones demuestran la efectividad de la nueva arquitectura, al tiempo que se mantiene un rendimiento similar (o mejorado) en términos de retardos y rendimiento en comparación con las PON clásicas. Por otro lado, se están desarrollando técnicas de ahorro de energía y mejora de la eficiencia energética en redes PON, y dado que la contribución de las redes de acceso al consumo total de energía es importante, la eficiencia energética se ha convertido en un requisito cada vez más importante. Se han propuesto varias técnicas por parte de otros autores para aumentar la eficiencia energética en las redes PON, relacionadas con algoritmos DBA (Dynamic Bandwidth Allocation) centralizados, pero las ventaja del ahorro de energía en un DBA distribuido no se ha explorado todavía. Por ello nuestra segunda contiribución es un algoritmo distribuido de asignación dinámica de ancho de banda energéticamente eficiente tanto para los canales ascendentes como descendentes de EPON para mejorar la eficiencia energética en las redes EPON. El algoritmo propuesto analiza el estado de cola de las ONU y la OLT para apagar el transmisor y/o el receptor de una ONU cuando no hay tráfico en sentido ascendente o descendente. Hemos podido combinar la ventaja de un DBA distribuido como DDSPON (que asegura retardos más pequeños, debido al menor tiempo que DDSPON necesita para asignar las ranuras de transmisión) y las características de ahorro de energía (al precio de tener retardos de paquete más grandes debido al hecho de que apagar los transmisores hace que las colas de paquetes crezcan). Nuestro algoritmo de DBA propuesto minimiza el consumo de energía de la ONU en una amplia gama de cargas de red, mientras mantiene a un nivel aceptable la penalización introducida en términos de utilización del canal y retardos

IP and ATM integration: A New paradigm in multi-service internetworking

ATM is a widespread technology adopted by many to support advanced data communication, in particular efficient Internet services provision. The expected challenges of multimedia communication together with the increasing massive utilization of IP-based applications urgently require redesign of networking solutions in terms of both new functionalities and enhanced performance. However, the networking context is affected by so many changes, and to some extent chaotic growth, that any approach based on a structured and complex top-down architecture is unlikely to be applicable. Instead, an approach based on finding out the best match between realistic service requirements and the pragmatic, intelligent use of technical opportunities made available by the product market seems more appropriate. By following this approach, innovations and improvements can be introduced at different times, not necessarily complying with each other according to a coherent overall design. With the aim of pursuing feasible innovations in the different networking aspects, we look at both IP and ATM internetworking in order to investigating a few of the most crucial topics/ issues related to the IP and ATM integration perspective. This research would also address various means of internetworking the Internet Protocol (IP) and Asynchronous Transfer Mode (ATM) with an objective of identifying the best possible means of delivering Quality of Service (QoS) requirements for multi-service applications, exploiting the meritorious features that IP and ATM have to offer. Although IP and ATM often have been viewed as competitors, their complementary strengths and limitations from a natural alliance that combines the best aspects of both the technologies. For instance, one limitation of ATM networks has been the relatively large gap between the speed of the network paths and the control operations needed to configure those data paths to meet changing user needs. IP\u27s greatest strength, on the other hand, is the inherent flexibility and its capacity to adapt rapidly to changing conditions. These complementary strengths and limitations make it natural to combine IP with ATM to obtain the best that each has to offer. Over time many models and architectures have evolved for IP/ATM internetworking and they have impacted the fundamental thinking in internetworking IP and ATM. These technologies, architectures, models and implementations will be reviewed in greater detail in addressing possible issues in integrating these architectures s in a multi-service, enterprise network. The objective being to make recommendations as to the best means of interworking the two in exploiting the salient features of one another to provide a faster, reliable, scalable, robust, QoS aware network in the most economical manner. How IP will be carried over ATM when a commercial worldwide ATM network is deployed is not addressed and the details of such a network still remain in a state of flux to specify anything concrete. Our research findings culminated with a strong recommendation that the best model to adopt, in light of the impending integrated service requirements of future multi-service environments, is an ATM core with IP at the edges to realize the best of both technologies in delivering QoS guarantees in a seamless manner to any node in the enterprise

Contributions towards softwarization and energy saving in passive optical networks

Ths thesis is a result of contributions to optimize and improve the network management systme and power consumption in Passive Optical Network (PON). Passive Optical Network elements such as Optical Line Terminal (OLT) and Optical Network Units (ONUs) are currently managed by inflexible legacy network management systems. Software-Defined Networking (SDN) is a new networking paradigm that improves the operation and management of networks by decoupling control plane from data plane. Currently, network management in PON networks is not always automated nor normalized. One goal of the researchers in optical networking is to improve the programmability, efficiency, and global optimization of network operations, in order to minimize both Capital Expenditure (CAPEX) and Operational Expenditure (OPEX) by reducing the complexity of devices and its operation. Therefore, it makes sense to use an SDN approach in order to manage the passive optical network functionalities and migrating must of the upper layer functions to the SDN controller. Many approaches have already addressed the topic of applying the SDN architecture in PON networks. However; the focus was usually on facilitating the deployment of SDN-based service and so Service Interoperability remains unexplored in detail. The main challenge toward this goal is how to make compatible the synchronous nature of the EPON media access control protocols with the asynchronous architecture of SDN, and in particular, OpenFlow. In our proposed architecture, the OLT is partially virtualized and some of its functionalities are allocated to the core network management system, while the OLT itself is replaced by an OpenFlow switch. A new MultiPoint MAC Control (MPMC) sublayer extension based on the OpenFlow protocol is presented. The OpenFlow switch is extended with synchronous ports to retain the time-critical nature of the EPON network. Our simulation-based results demonstrate the effectiveness of the new architecture, while retaining a similar (or improved) performance in term of delay and throughput when compared to legacy PONs. Nowadays, many researchers are working simultaneously to develop power saving techniques and improves energy efficiency in the PON network, and since the contribution of access networks to the global energy consumption is large, energy efficiency has become an increasingly important requirement in designing access networks. Therefore, energy-saving approaches are being investigated to provide high performance and consume less energy. Several techniques have been proposed to increase energy efficiency in PON networks. Such techniques are related to the centeralized DBA but the advantage of power saving in a distributed DBA remains untouched. We present a distributed energy-efficient Dynamic Bandwidth Allocation (DBA) algorithm for both the upstream and downstream channels of EPON to improve energy efficiency in EPON networks. The proposed algorithm analyzes the queue status of the ONUs and OLT in order to power-off the transmitter and/or receiver of an ONU whenever there is no upstream or downstream traffic. We have been able to combine the advantage of a distributed DBA such as DDSPON (a smaller packet delay, due to the shorter time needed by DDSPON to allocate the transmission slots) and the energy-saving features (that come at a price of longer packet delays due to the fact that switching off the transmitters make the packet queues grow). Our proposed DBA algorithm minimizes the ONU energy consumption across a wide range of network loads, while maintaining at an acceptable level the penalty introduced in terms of channel utilization and packet delay.Las contribuciones de esta tesis se centran en mejorar el sistema de gestión de red y el consumo de energía en redes de acceso ópticas pasivas (PON). Los elementos de las redes PON, como el terminal de línea óptica (OLT) y las unidades de red ópticas (ONU), se gestionan actualmente mediante sistemas poco flexibles. El nuevo paradigma de redes definidas por software (SDN) mejora la gestión de redes al desacoplar el plano de control del plano de datos. Actualmente, la gestión de redes PON no está automatizada ni normalizada. Uno de los objetivos de los investigadores en redes ópticas es mejorar la programabilidad, la eficiencia y la optimización global de las operaciones de red, con el fin de minimizar tanto el gasto de capital (CAPEX) como el gasto operativo (OPEX) al reducir la complejidad de los dispositivos y su funcionamiento. Por lo tanto, tiene sentido utilizar un enfoque SDN para gestionar las funciones de red óptica pasiva y migrar algunas de las funciones PON de capas superiores al controlador SDN. Otros investigadores han estudiado esta aproximación. sin embargo; el enfoque generalmente estaba en facilitar la implementación del servicio basado en SDN y, por lo tanto, la interoperabilidad de los servicios permanecía sin ser explorado en detalle. El principal desafío hacia este objetivo es cómo compatibilizar la naturaleza síncrona de los protocolos de control de acceso a medios EPON con la arquitectura asíncrona de SDN y, en particular, OpenFlow. En nuestra propuesta de arquitectura, la OLT se virtualiza parcialmente y algunas de sus funcionalidades se asignan al sistema de gestión de red centralizado, mientras que la OLT se reemplaza por un conmutador OpenFlow. Proponemos una nueva extensión de la subcapa de control múltiple de MAC (MPMC) basada en el protocolo OpenFlow. El conmutador OpenFlow se amplía con puertos síncronos para asegurar la naturaleza de tiempo real de la red EPON. Nuestros resultados basados ¿¿en simulaciones demuestran la efectividad de la nueva arquitectura, al tiempo que se mantiene un rendimiento similar (o mejorado) en términos de retardos y rendimiento en comparación con las PON clásicas. Por otro lado, se están desarrollando técnicas de ahorro de energía y mejora de la eficiencia energética en redes PON, y dado que la contribución de las redes de acceso al consumo total de energía es importante, la eficiencia energética se ha convertido en un requisito cada vez más importante. Se han propuesto varias técnicas por parte de otros autores para aumentar la eficiencia energética en las redes PON, relacionadas con algoritmos DBA (Dynamic Bandwidth Allocation) centralizados, pero las ventaja del ahorro de energía en un DBA distribuido no se ha explorado todavía. Por ello nuestra segunda contiribución es un algoritmo distribuido de asignación dinámica de ancho de banda energéticamente eficiente tanto para los canales ascendentes como descendentes de EPON para mejorar la eficiencia energética en las redes EPON. El algoritmo propuesto analiza el estado de cola de las ONU y la OLT para apagar el transmisor y/o el receptor de una ONU cuando no hay tráfico en sentido ascendente o descendente. Hemos podido combinar la ventaja de un DBA distribuido como DDSPON (que asegura retardos más pequeños, debido al menor tiempo que DDSPON necesita para asignar las ranuras de transmisión) y las características de ahorro de energía (al precio de tener retardos de paquete más grandes debido al hecho de que apagar los transmisores hace que las colas de paquetes crezcan). Nuestro algoritmo de DBA propuesto minimiza el consumo de energía de la ONU en una amplia gama de cargas de red, mientras mantiene a un nivel aceptable la penalización introducida en términos de utilización del canal y retardos.Postprint (published version