Redes de acesso definidas por software

Mestrado em Engenharia Electr onica e Telecomunica c~oesWith the increase of internet usage and the exponential growth of bandwidth consumption due to the increasing number of users of new generation equipments and the creation of new services that consume increasingly higher bandwidths, it's necessary to nd solutions to meet these new requirements. Passive optical networks (PONs) promise to solve these problems by providing a better service to users and providers. PON networks are very attractive since they don't depend on active elements between their end points, leading to lower maintenance costs and better operational e ciency. PON technologies addressed in this dissertation are the G-PON (Gigabit PON), currently standardized and implemented in access networks across the world, and the NG-PON2 (Next-Generation PON 2), which is the next step on access networks evolution and is currently on the process of study and standardization. The NG-PON2 must co-exist on the same optical distribution network of the G-PON, so it re-utilizes the already built infrastructures and consequently protect providers initial investment. Software De ned Networks (SDN) is an emerging architecture that decouples network control and forwarding functions from the hardware they belong, making possible for network control to be programmable, enabling the implementation of solutions capable of solving the increasing complexity of the networks problem and the creation of innovative services. The study main focus is the SDN as an enabling mechanism for network elements virtualization. In this dissertation is studied the G-PON and NG-PON2 architectures in the context of the ITU-T G.984.x and G.989.x recommendations respectively, and the study of the SDN technology through documentation available online. And based on the studies made it's going to be proposed a server architecture that enables the control of G-PON and NG-PON2 infrastructure elements, introducing virtualization SDN concepts on access networks.Com o crescimento da utiliza c~ao da Internet e o consumo de largura de banda a crescer exponencialmente devido ao crescente n umero de utilizadores de equipamentos de nova gera c~ao e a cria c~ao de novos servi cos que consomem cada vez maiores larguras de banda, e necess ario encontrar solu c~oes para satisfazer estes novos requisitos. As redes opticas passivas (PON) prometem solucionar esses problemas, oferecendo um melhor servi co aos utilizadores e provedores. As redes PON s~ao muito atrativas pois n~ao dependem de elementos ativos entre os seus pontos terminais, resultando em baixos custos de manuten c~ao e uma maior e ci^encia de opera c~oes. As tecnologias PON abordadas nesta disserta c~ao s~ao o G-PON (Gigabit PON), actualmente padronizada e implementada nas redes de accesso pelo mundo, e o NG-PON2 (Next-Generation PON 2), que ser a o pr oximo passo na evolu c~ao das redes de acesso e que atualmente se encontra em processo de estudo e padroniza c~ao. O NG-PON2 deve co-existir na mesma rede de distribui c~ao otica do G-PON, de forma a re-utilizar as infrastruturas j a construidas e consequentemente proteger o investimento inicial dos provedores. As redes de nidas por software (SDN) e uma arquitetura emergente que desassocia o controlo da rede e fun c~oes de encaminhamento do hardware a que pertencem, possibilitando a que o controlo da rede seja program avel, permitindo a implementa c~ao de solu c~oes capazes de resolver o problema do aumento da complexidade das redes e cria c~ao de servi cos inovadores. O principal foco de estudo ser a nas SDN como mecanismo de virtualiza c~ao dos elementos da rede. Nesta disserta c~ao e estudado as arquiteturas do G-PON e NG-PON2 no contexto das recomenda c~oes do ITU-T G.984.x e G.989.x respetivamente, e o estudo da tecnologia SDN atrav es da documenta c~ao dispon vel online. Com base nos estudos efetuados ir a ser sugerido uma arquitetura de um servidor que permite o controlo de elementos da infrastrutura G-PON e NG-PON2, intoduzindo os conceitos das SDN e virtualiza c~ao na rede de acesso

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

Virtual network function development for NG-PON Access Network Architecture

Dissertação de mestrado em Engenharia de Redes e Serviços TelemáticosThe access to Internet services on a large scale, high throughput and low latency has grown at a very high pace over time, with a growing demand for media content and applications increasingly oriented towards data consumption. This fact about the use of data at the edge of the network requires the Central Offices (CO) of telecommunication providers, to be pre pared to absorb these demands. COs generally offer data from various access methods, such as Passive Optical Network (PON) technologies, mobile networks, copper wired and oth ers. For each of these technologies there may be different manufacturers that support only their respective hardware and software solutions, although they all share different network resources and have management, configuration and monitoring tools (Fault, Configuration, Accounting, Performance, and Security management - FCAPS) similar, but being distinct and isolated from each other, which produces huge investment in Capital Expenditure (CAPEX) and Operational Expenditure (OPEX) and can cause barriers to innovation. Such panora mas forced the development of more flexible, scalable solutions that share platforms and net work architectures that can meet this need and enable the evolution of networks. It is then proposed the architecture of Software-Defined Network (SDN) which has in its proposal to abstract the control plane from the data plane, in addition to the virtualization of several Net work Function Virtualization (NFV). The SDN architecture allows APIs and protocols such as Openflow, NETCONF / YANG, RESTCONF, gRPC and others to be used so that there is communication between the various hardware and software elements that compose the net work and consume network resources, such as services AAA, DHCP, routing, orchestration, management or various applications that may exist in this context. This work then aims at the development of a virtualized network function, namely a VNF in the context of network security to be integrated as a component of an architecture guided by the SDN paradigm applied to broadband networks, and also adherent to the architecture OB-BAA promoted by the Broadband Forum. Such OB-BAA architecture fits into the initia tive to modernize the Information Technology (IT) components of broadband networks, more specifically the Central Offices. With such development, it was intended to explore the con cepts of network security, such as the IEEE 802.1X protocol applied in NG-PON networks for authentication and authorization of new network equipment. To achieve this goal, the development of the applications was based on the Golang language combined with gRPC programmable interfaces for communication between the various elements of the architec ture. Network emulators were initially used, and then the components were ”containerized” and inserted in the Docker and Kubernetes virtualization frameworks. Finally, performance metrics were analyzed in the usage tests, namely computational resource usage metrics (CPU, memory and network I/O), in addition to the execution time of several processes performed by the developed applications.O acesso aos serviços de Internet em larga escala, alto débito e baixa latência têm crescido em um ritmo bastante elevado ao longo dos tempos, com uma demanda crescente por conteúdos de media e aplicações cada vez mais orientadas ao consumo de dados. Tal fato acerca da uti lização de dados na periferia da rede, obriga a que os Central Offices (CO) dos provedores de telecomunicações estejam preparados para absorver estas demandas. Os CO geralmente re cebem dados de diversos métodos de acesso, como tecnologias Passive Optical Network (PON), redes móveis, cabladas em cobre, entre outros. Para cada uma destas tecnologias pode haver diferentes fabricantes que suportam somente suas respetivas soluções de hardware e software, apesar de todas compartilharem diversos recursos de rede e possuírem ferramentas de gestão, configuração e monitoração (Fault-management, Configuration, Accounting, Performance e Segurança - FCAPS) similares, mas serem distintas e isoladas entre si, o que se traduz em um enorme investimento em Capital Expenditure (CAPEX) e Operational Expenditure (OPEX) e pode causar barreiras à inovação. Tais panoramas forçaram o desenvolvimento de soluções mais flexíveis, escaláveis e que compartilhem plataformas e arquiteturas de redes que pos sam suprir tal necessidade e possibilitar a evolução das redes. Propõe-se então a arquitetura de redes definidas por software (Software-Defined Network - SDN) que tem em sua proposta abstrair o plano de controle do plano de dados, além da virtualização de diversas funções de rede (Network Function Virtualization - NFV). A arquitetura SDN possibilita que API’s e pro tocolos como Openflow, NETCONF/YANG, RESTCONF, gRPC e outros, sejam utilizados para que haja comunicação entre os diversos elementos de hardware e software que estejam a compor a rede e a consumir recursos de redes, como serviços de AAA, DHCP, roteamento, orquestração, gestão ou diversas outras aplicações que possam existir neste contexto. Este trabalho visa então o desenvolvimento de uma função de rede virtualizada nomeada mente uma (Virtual Network Function - VNF) no âmbito de segurança de redes a ser integrada como um componente de uma arquitetura orientada pelo paradigma de SDN aplicado a re des de banda larga, e aderente também à arquitetura OB-BAA promovida pelo Broadband Fo rum. Tal arquitetura OB-BAA se enquadra na iniciativa de modernização dos componentes de Tecnologia da Informação (TI) das redes de banda larga, mais especificamente dos Cen tral Offices. Com tal desenvolvimento pretende-se explorar conceitos de segurança de redes, como o protocolo IEEE 802.1X aplicado em redes NG-PON para autenticação e autorização de novos equipamentos de rede. Para atingir tal objetivo, utilizou-se desenvolvimento de aplicações baseadas na linguagem Golang aliado com interfaces programáveis gRPC para comunicação entre os diversos elementos da arquitetura. Para emular tais componentes, utilizou-se inicialmente emuladores de rede, e em um segundo momento os componentes foram ”containerizados” e inseridos nos frameworks de virtualização Docker e Kubernetes.Por fim, foram analisadas métricas de desempenho nos testes executados, nomeadamente métricas de utilização de recursos computacionais (CPU, memória e tráfego de rede), além do tempo de execução de diversos processos desempenhados pelas aplicações desenvolvidas

Adaptive modulation techniques for passive optical networks

Smart use of fiber networks to increase capacity to the hom

Redes ópticas de acesso de nova geração : tecnologias e economia

Doutoramento em Engenharia Eletrotécnica - TelecomunicaçõesThe work presented herein, studies Next Generation Optical Access Networks (NG-OAN) economically (e.g. energy consumption) and technologically (e.g. rate, reach and dedicated/shared bandwidth). The work is divided into four main topics: energy efficiency in optical access architectures, novel spectrally efficient Long-Reach Passive Optical Networks (LR-PON), crosstalk impacts in heterogeneous and homogenous access networks and hybrid optical wireless transmissions. We investigate the impact of user profiles, optical distribution network topologies and equipment characteristics on resource sharing and power consumption in LR-PON. To have a clear vision on the energy consumption evolution of each part of NG-OAN, a model is proposed to evaluate the energy efficiency of optical access technologies. A spectrally efficient bidirectional Ultra-Dense Wavelength Division Multiplexing (UDWDM) PON architecture is developed using Nyquist shaped 16-ary quadrature amplitude modulation, offering up to 10 Gb/s service capabilities per user or wavelength. Performance of this system in terms of receiver sensitivity and nonlinear tolerance under different network transmission capacity conditions are experimentally optimized. In bi-directional transmis-sion, using frequency up/down-shifting of Nyquist pulse shaped signal from optical carrier, a full bandwidth allocation and easy maintenance of UDWDM networks as well as reduction of Rayleigh back-scattering are achieved. Moreover, self-homodyne detection is used to relax the laser linewidth requirement and digital signal processing complexity at the optical network unit. Simplified numerical model to estimate the impact of Raman crosstalk of multi-system next generation PONs in video overlay is proposed. Coexistence of considered G.98X ITU-T series and coherent multi-wavelength systems is considered and assessed. Additionally, the performances of bidirectional hybrid optical wireless coherent PONs over different optical distribution network power budgets and hybrid splitting ratios are evaluated.O trabalho aqui apresentado estuda redes óticas de acesso de próxima geração (NG-OAN) nas vertentes económica (consumo de energia) e tecnológica (taxa, alcance e largura de banda dedicada/partilhada). O trabalho está dividido em quatro grandes temas de investigação: a eficiência energética em arquiteturas de acesso ótico, as redes óticas passivas de longo alcance (LR-PON) com nova eficiência espetral, o impacto da diafonia em redes de acesso heterogéneas e homogéneas e as transmissões ópticas híbridas com tecnologias sem fio. Investiga-se o impacto dos perfis dos utilizadores, as tipologias da rede de distribuição ótica, as características do equipamento de partilha de recursos e o consumo de energia em LR-PON. Para se ter uma visão clara sobre o consumo de energia de cada parte das NG-OAN, é proposto um modelo para avaliar a eficiência energética das tecnologias de acesso óticas. Desenvolve-se uma arquitetura PON bi-direcional com elevada eficiência espetral, recorrendo a multiplexagem por divisão de comprimento de onda ultra-densa (UDWDM), modulação de amplitude em quadratura com formato de impulso de Nyquist, oferecendo até 10 Gb/s por utilizador/comprimento de onda. O desempenho deste sistema em termos de sensibilidade do recetor e da tolerância à resposta não linear do canal de comunicação, sob diferentes condições de transmissão, é avaliado experimentalm-ente. Em transmissão bi-direcional, utilizando desvio de frequência (cima/baixo) do impulso com formato de Nyquist relativo à portadora ótica conseguiu-se uma alocação de largura de banda completa e uma manutenção mais simplificada de redes UDWDM, bem como a redução do espalhamento de Rayleigh. Além disso, a deteção auto-homodina é usada para relaxar o requisito de largura de linha do laser e a complexidade do processamento digital de sinal nas unidades da rede ótica. Propõe-se um modelo numérico simplificado para estimar o impacto da diafonia de Raman em sistemas PON de próxima geração, com sobreposição do sinal de vídeo. É analisada a coexistência da série G.98X ITU-T e são considerados e avaliados sistemas coerentes multi-comprimento de onda. Adicionalmente avaliam-se os desempenhos de PONs bi-direcionais híbridas, considerando tecnologia coerente e propagação por espaço livre, para diferentes balanços de potência e taxas de repartição na rede ótica de distribuição

Analysis and optimisation of semiconductor reflective modulators for optical networks

Reflective modulators based on the combination of an electroabsorption modulator (EAM) and semiconductor optical amplifier (SOA) are attractive devices for applications in long reach carrier distributed passive optical networks (PONs) due to the gain provided by the SOA and the high speed and low chirp modulation of the EAM. Integrated R-EAM-SOAs have experimentally shown two unexpected and unintuitive characteristics which are not observed in a single pass transmission SOA: the clamping of the output power of the device around a maximum value and low patterning distortion despite the SOA being in a regime of gain saturation. In this thesis a detailed analysis is carried out using both experimental measurements and modelling in order to understand these phenomena. For the first time it is shown that both the internal loss between SOA and R-EAM and the SOA gain play an integral role in the behaviour of gain saturated R-EAM-SOAs. Internal loss and SOA gain are also optimised for use in a carrier distributed PONs in order to access both the positive effect of output power clamping, and hence upstream dynamic range reduction, combined with low patterning operation of the SOA Reflective concepts are also gaining interest for metro transport networks and short reach, high bit rate, inter-datacentre links. Moving the optical carrier generation away from the transmitter also has potential advantages for these applications as it avoids the need for cooled photonics being placed directly on hot router line-cards. A detailed analysis is carried out in this thesis on a novel colourless reflective duobinary modulator, which would enable wavelength flexibility in a power-efficient reflective metro node

View on 5G Architecture: Version 1.0

The current white paper focuses on the produced results after one year research mainly from 16 projects working on the abovementioned domains. During several months, representatives from these projects have worked together to identify the key findings of their projects and capture the commonalities and also the different approaches and trends. Also they have worked to determine the challenges that remain to be overcome so as to meet the 5G requirements. The goal of 5G Architecture Working Group is to use the results captured in this white paper to assist the participating projects achieve a common reference framework. The work of this working group will continue during the following year so as to capture the latest results to be produced by the projects and further elaborate this reference framework. The 5G networks will be built around people and things and will natively meet the requirements of three groups of use cases: • Massive broadband (xMBB) that delivers gigabytes of bandwidth on demand • Massive machine-type communication (mMTC) that connects billions of sensors and machines • Critical machine-type communication (uMTC) that allows immediate feedback with high reliability and enables for example remote control over robots and autonomous driving. The demand for mobile broadband will continue to increase in the next years, largely driven by the need to deliver ultra-high definition video. However, 5G networks will also be the platform enabling growth in many industries, ranging from the IT industry to the automotive, manufacturing industries entertainment, etc. 5G will enable new applications like for example autonomous driving, remote control of robots and tactile applications, but these also bring a lot of challenges to the network. Some of these are related to provide low latency in the order of few milliseconds and high reliability compared to fixed lines. But the biggest challenge for 5G networks will be that the services to cater for a diverse set of services and their requirements. To achieve this, the goal for 5G networks will be to improve the flexibility in the architecture. The white paper is organized as follows. In section 2 we discuss the key business and technical requirements that drive the evolution of 4G networks into the 5G. In section 3 we provide the key points of the overall 5G architecture where as in section 4 we elaborate on the functional architecture. Different issues related to the physical deployment in the access, metro and core networks of the 5G network are discussed in section 5 while in section 6 we present software network enablers that are expected to play a significant role in the future networks. Section 7 presents potential impacts on standardization and section 8 concludes the white paper

Dynamically reconfigurable long-reach PONs for high capacity access

Fibre-to-the-Premises (FTTP) is currently seen as the ultimate in high-speed transmission technologies for delivering ubiquitous bandwidth to customers. However, as the deployment of network infrastructure requires a substantial investment, the main obstacle to fibre deployment is that of financial viability. With this in mind, a logical strategy to offset network costs is to optimise the infrastructure in order to capture a greater amount of customers over larger areas with increased sharing of network resources. This approach prompted the design of a long-reach passive optical network (LR-PON) in which the physical reach and split of a conventional PON is significantly increased through the use of intermediate optical amplification. In particular, the LR-PON architecture effectively integrates the metro and access networks enabling the majority of local exchange sites to be bypassed resulting in a substantial reduction in field equipment requirements and power consumption. Furthermore, the extension in physical reach and split can be coupled with an increased information capacity through the use of time- and wavelength division multiplexing (TWDM) which serve to exploit the large bandwidth capabilities offered by single-mode fibre. In this project, reconfigurable TWDM LR-PON architectures which dynamically exploit the wavelength domain are proposed, assembled and characterised in order to establish an economically viable ‘open access’ environment that is capable of concurrently supporting multiple operators offering converged services (residential, business and mobile) to support diverse customer requirements and locations. The main investigations in this work address the key physical layer challenges within such wavelength-agile networks. In particular, a range of experimental analysis has been carried out in order to realise the critical component technologies which include low-cost, 10G-capable, wavelength-tuneable transmitters for mass-market residential deployment and the development of gain-stabilised optical amplifier nodes to support the targeted physical reach (≥ 100km) and split (≥ 512). Finally, the feasibility of the proposed dynamically reconfigurable LR-PON configurations as a flexible and cost-effective solution for future access networks is verified through full-scale network demonstrations using an experimental laboratory test-bed