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

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

Enhanced dynamic bandwidth algorithms for passive optical networks

(English) The telecommunications industry faces rapid changes due to the deployment of ultra-high speed access networks (5G and beyond, fiber-to-the-home), promising unparalleled experiences with high bandwidth and low latency. However, this transition brings challenges. With the surge in smart device numbers and bandwidth demand, optimizing network architecture, management, and resource usage is crucial for cost-efficiency. Passive Optical Networks (PONs) offer efficient broadband access for residential and commercial sectors, with advantages like energy efficiency and robust security and high performance. Leading organizations, such as IEEE and ITU-T, are actively developing standards to increase the capabilities of next-generation PONs. The goal is to meet the demands by implementing innovative mechanisms for efficient management, resource allocation, QoS, energy savings, and low latency. Next-generation PONs have introduced the use of multiple wavelengths based on TWDM techniques. However, managing multiple wavelengths presents challenges, as DBA algorithms need to consider both the time and wavelength dimensions of the network. This follows a Joint Time and Wavelength Scheduling (JTWS) scheme, which requires complex implementation. TWDM-PON also utilizes tunable transceivers in ONUs to switch between wavelengths, but this introduces a delay called Laser Tuning Time (LTT) which is often ignored, but it is an important consideration when designing our DBA algorithms. Additionally, there is a demand to integrate metro and access networks for streamlined telecom infrastructure. Long Reach PON (LRPON) offers a solution by expanding coverage from 20 km to 100 km, enabling high-speed, long-distance data transmission over optical fibers. This reduces the need for central offices, resulting in cost savings. However, the extended reach of LRPONs introduces new challenges, particularly in the area of DBA algorithms. Traditional DBA algorithms like IPACT may not be as efficient for LRPONs due to increased propagation delays and round-trip times (RTT) between the OLT and ONUs. To address these challenges, a novel DBA algorithm called the Distance Weighted DBA (DWDBA) algorithm is proposed. This thesis delves into the limitations of traditional DBA algorithms and proposes novel Enhanced DBA solutions for PONs. Leveraging techniques such as the Longest Processing Time (LPT) scheduling method to minimize queue delays, our DBAs also consider the concept of laser tuning time to bring a practical, real-world approach to our system. The main contributions of this thesis are: - Incorporating the often-overlooked laser tuning time (LTT) concept in our analysis of DBA for TWDM PONs, therefore obtaining more realistic results. - Introducing an innovative algorithm for PONs employing LPT to minimize queue delay and enhance throughput, resulting in a notable reduction (up to 73%) with respect to the queue delay when compared to IPACT. - Developing a Distance Weighted DBA (DWDBA), specifically tailored for LRPONs, aimed at preventing the penalization of ONUs located farther from the OLT. This results in improving up to 30% and 10% the queue delay and throughput, respectively, over IPACT. The effectiveness of these proposed algorithms is rigorously evaluated through comprehensive simulations, demonstrating their potential to meet the demands of future networks.(Català) La indústria de les telecomunicacions s'enfronta a canvis ràpids a causa del desplegament de xarxes d'accés d'alta velocitat (5G i més enllà, fibra fins a la llar), prometent experiències inigualables amb gran amplada de banda i baixa latència. Tanmateix, aquesta transició comporta reptes. Amb l'augment del nombre de dispositius intelꞏligents i la demanda d'ample de banda, l'optimització de l'arquitectura de xarxa, i la gestió dels recursos esdevenen crucials per a l'eficiència i rendibilitat d'operació. Les xarxes òptiques passives (PON) ofereixen un accés eficient de banda ampla per als sectors residencial i comercial, amb avantatges com l'eficiència energètica i una seguretat robusta i un alt rendiment. Els organismes d'estandardització, entre ells l'IEEE i la ITU-T, estan desenvolupant de manera activa estàndards per augmentar les capacitats de les PON de nova generació. L'objectiu és satisfer les demandes mitjançant la implementació de mecanismes innovadors de gestió eficient, assignació de recursos, QoS, estalvi d'energia i baixa latència. Les PON de nova generació han introduït l'ús de múltiples longituds d'ona basades en tècniques TWDM. Tanmateix, la gestió de diverses longituds d'ona presenta reptes, ja que els algorismes d'assignació dinàmica d'amplada de banda (DBA) han de tenir en compte tant les dimensions de temps com de longitud d'ona de la xarxa. Això segueix un esquema de programació conjunta de temps i longitud d'ona (JTWS), que comporta una implementació complexa. TWDM-PON també utilitza transceptors ajustables a les ONU per canviar entre longituds d'ona, fet que introdueix un retard anomenat Laser Tuning Time (LTT) que sovint s'ignora, però és important considerar-lo a l'hora de dissenyar els nostres algorismes DBA. Addicionalment, hi ha una necessitat per integrar xarxes metropolitanes i d'accés per a obtenir una infraestructura de telecomunicacions racionalitzada. La tecnologia Long Reach PON (LRPON) ofereix una solució ampliant la cobertura de les PON de 20 km a 100 km, permetent la transmissió de dades d'alta velocitat i llarga distància a través de fibres òptiques. Això redueix la necessitat de centrals, el que resulta en un estalvi de costos. Tanmateix, l'abast estès de les LRPON introdueix nous reptes, especialment en l'àrea dels algorismes DBA. Els algorismes DBA tradicionals com IPACT no poden ser tan eficients a l'escenari LRPON a causa de l'augment dels retards de propagació i els temps d'anada i tornada (RTT) entre l'OLT i les ONU. Per abordar aquests reptes, es proposa un algorisme de DBA nou anomenat algorisme DBA ponderat per distància (DWDBA). Aquesta tesi aprofundeix en les limitacions dels algorismes tradicionals de DBA i proposa noves solucions. Aprofitant tècniques com el mètode de programació del temps de processament més llarg (LPT) per minimitzar els retards de la cua, els nostres DBA també consideren el concepte de temps de sintonització làser per oferir un enfocament pràctic. Les principals aportacions d'aquesta tesi són: - Incorporació del concepte de temps de sintonització làser (LTT) que sovint es passa per alt en l'anàlisi de DBA per a PON TWDM, obtenint així resultats més realistes. - Introducció d'un algorisme innovador per a PON que utilitza la tècnica LPT per minimitzar el retard de la cua i millorar el rendiment, donant lloc a una reducció notable (fins a un 73%) respecte al retard de la cua en comparació amb IPACT. - Desenvolupament d'un DBA amb ponderació per distància (DWDBA), específicament dissenyat per a LRPON, amb l'objectiu d'evitar la penalització de les ONU situades més allunyades de l'OLT. Això es tradueix en millores de fins a un 30% i un 10% del retard i del throughput, respectivament, comparat amb IPACT. L'efectivitat d'aquests algorismes proposats s'avalua rigorosament mitjançant simulacions exhaustives, demostrant el seu potencial per satisfer les demandes de les xarxes futures.DOCTORAT EN ENGINYERIA TELEMÀTICA (Pla 2013

Networking technology adoption : system dynamics modeling of fiber-to-the-home

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology, Management, and Policy Program, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Page 244 blank.Includes bibliographical references (p. 241-243).A system dynamics model is developed and run to study the adoption of fiber-to-the-home as a residential broadband technology. Communities that currently do not have broadband in the United States are modeled. This case is of particular interest to U.S. policymakers, but also relevant to other regions concerned with economic development in rural areas. The model is used to explore the effects of government policy on fiber-to-the-home deployment and on the telecommunications supply chain. The research finds that government policy relating to broadband deployment has been based on a weak understanding of the dynamics involved, resulting in trial and error policy making that has unintended consequences. The thesis shows that the current monitoring of broadband deployment by the Federal Communications Commission is inadequate to contribute to the formation of reasoned policy decisions. The model is used to explore the consequences that different regulatory scenarios have on fiber-to-the-home deployment. Among the policy choices considered are: resale of fiber-to-the-home lines to competitive providers; low cost government loans for commercial deployments; rapid deployment to all communities currently without service; and a ban on municipal deployments. The current Rural Utilities Service loan program is also included in the model and its effects are analyzed. The model is used to examine the consequences for the optoelectronics industry of different deployment scenarios. It shows that the interests of consumers, regulators, and even service providers are in conflict with the interests of the optoelectronics industry which provides a critical component necessary for the service.(cont.) Strategies to help mitigate that conflict and to promote the health of the components industry are explored. Deployment of fiber-to-the-home is costly, and cost recovery is difficult for both incumbent and competitive service providers, especially in rural and suburban regions that do not currently have service. The interests of policy makers, service providers, and component suppliers need to be aligned to implement effective policy that encourages the deployment of broadband to unserved regions. The Federal Communications Commission needs to rearchitect its monitoring of service providers and their activities to better understand the status of deployment and how its policies can help or hinder.by Andjelka Kelic.Ph.D

Telecommunication Systems

This book is based on both industrial and academic research efforts in which a number of recent advancements and rare insights into telecommunication systems are well presented. The volume is organized into four parts: "Telecommunication Protocol, Optimization, and Security Frameworks", "Next-Generation Optical Access Technologies", "Convergence of Wireless-Optical Networks" and "Advanced Relay and Antenna Systems for Smart Networks." Chapters within these parts are self-contained and cross-referenced to facilitate further study

Software Defined Applications in Cellular and Optical Networks

abstract: Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. A novel access backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations, e.g., LTE eNBs, and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs) has been introduced to address the bottleneck. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Based on software defined networking (SDN) a management mechanism that allows multiple operator to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells has been proposed. This dissertation also comprehensively survey the studies that examine the SDN paradigm in optical networks. Along with the PHY functional split improvements, the performance of Distributed Converged Cable Access Platform (DCCAP) in the cable architectures especially for the Remote-PHY and Remote-MACPHY nodes has been evaluated. In the PHY functional split, in addition to the re-use of infrastructure with a common FFT module for multiple technologies, a novel cross functional split interaction to cache the repetitive QAM symbols across time at the remote node to reduce the transmission rate requirement of the fronthaul link has been proposed.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201