228 research outputs found

    Ontwerp en evaluatie van content distributie netwerken voor multimediale streaming diensten.

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    Traditionele Internetgebaseerde diensten voor het verspreiden van bestanden, zoals Web browsen en het versturen van e-mails, worden aangeboden via één centrale server. Meer recente netwerkdiensten zoals interactieve digitale televisie of video-op-aanvraag vereisen echter hoge kwaliteitsgaranties (QoS), zoals een lage en constante netwerkvertraging, en verbruiken een aanzienlijke hoeveelheid bandbreedte op het netwerk. Architecturen met één centrale server kunnen deze garanties moeilijk bieden en voldoen daarom niet meer aan de hoge eisen van de volgende generatie multimediatoepassingen. In dit onderzoek worden daarom nieuwe netwerkarchitecturen bestudeerd, die een dergelijke dienstkwaliteit kunnen ondersteunen. Zowel peer-to-peer mechanismes, zoals bij het uitwisselen van muziekbestanden tussen eindgebruikers, als servergebaseerde oplossingen, zoals gedistribueerde caches en content distributie netwerken (CDN's), komen aan bod. Afhankelijk van de bestudeerde dienst en de gebruikte netwerktechnologieën en -architectuur, worden gecentraliseerde algoritmen voor netwerkontwerp voorgesteld. Deze algoritmen optimaliseren de plaatsing van de servers of netwerkcaches en bepalen de nodige capaciteit van de servers en netwerklinks. De dynamische plaatsing van de aangeboden bestanden in de verschillende netwerkelementen wordt aangepast aan de heersende staat van het netwerk en aan de variërende aanvraagpatronen van de eindgebruikers. Serverselectie, herroutering van aanvragen en het verspreiden van de belasting over het hele netwerk komen hierbij ook aan bod

    Broadband access technologies

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    Broadband technologies have view great growth over the past decade. But, the main part of this development and growth has been in the core networks, and the capacity of the access network to delivery broadband services remains as a challenge ("last mile problem"). The access network remains a bottleneck in terms of the bandwidth and service quality it affords the end user. By other side, the access network is much more spread geographically and covers larger areas. Then, this part of the network is usually the most expensive component in terms of capital investment and OAM cost. Some studies reefer that this networks required 70% of the total investment. Several access technologies can be used in this part of the network, which can be used to resolve the bandwidth bottleneck and the investment problem: xDSL, HFC, FTTx, FWA, WiMAX, PLC, Satellite, etc. This paper presents a methodology and a tool that compare and evaluate broadband access technologies. The paper presents a techno-economic analysis of eight broadband technologies for access networks: digital subscriber line (DSL), hybrid fiber coax (HFC), power line communications (PLC), fiber to the home (FTTH), fiber to the curb (FTTC), fiber to the cabinet (FTTCab), and wireless alternatives such as WiMAX and satellite. Several actors (such operators, service providers, …) could use this tool to compare different technological solutions, forecast deployment costs, compare different scenarios, etc

    Otimização de distribuição de conteúdos multimédia utilizando software-defined networking

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    The general use of Internet access and user equipments, such as smartphones, tablets and personal computers, is creating a new wave of video content consumption. In the past two decades, the Television broadcasting industry went through several evolutions and changes, evolving from analog to digital distribution, standard definition to high definition TV-channels, form the IPTV method of distribution to the latest set of technologies in content distribution, OTT. The IPTV technology introduced features that changed the passive role of the client to an active one, revolutionizing the way users consume TV content. Thus, the clients’ habits started to shape the services offered, leading to an anywhere and anytime offer of video content. OTT video delivery is a reflection of those habits, meeting the users’ desire, introducing several benefits discussed in this work over the previous technologies. However, the OTT type of delivery poses several challenges in terms of scalability and threatens the Telecommunications Operators business model, because OTT companies use the Telcos infrastructure for free. Consequently, Telecommunications Operators must prepare their infrastructure for future demand while offering new services to stay competitive. This dissertation aims to contribute with insights on what infrastructure changes a Telecommunications Operator must perform with a proposed bandwidth forecasting model. The results obtained from the forecast model paved the way to the proposed video content delivery method, which aims to improve users’ perceived Quality-of-Experience while optimizing load balancing decisions. The overall results show an improvement of users’ experience using the proposed method.A generalização do acesso à Internet e equipamentos pessoais como smartphones, tablets e computadores pessoais, está a criar uma nova onda de consumo de conteúdos multimedia. Nas ultimas duas décadas, a indústria de transmissão de Televisão atravessou várias evoluções e alterações, evoluindo da distribuição analógica para a digital, de canais de Televisão de definição padrão para alta definição, do método de distribuição IPTV, até ao último conjunto de tecnologias na distribuição de conteúdos, OTT. A tecnologia IPTV introduziu novas funcionalidades que mudaram o papel passivo do cliente para um papel activo, revolucionando a forma como os utilizadores consumem conteúdos televisivos. Assim, os hábitos dos clientes começaram a moldar os serviços oferecidos, levando à oferta de consumo de conteúdos em qualquer lugar e em qualquer altura. A entrega de vídeo OTT é um reflexo destes hábitos, indo ao encontro dos desejos dos utilizadores, que introduz inúmeras vantagens sobre outras tecnologias discutidas neste trabalho. No entanto, a entrega de conteúdos OTT cria diversos problemas de escalabilidade e ameaça o modelo de negócio das Operadoras de Telecomunicações, porque os fornecedores de serviço OTT usam a infraestrutura das mesmas sem quaisquer custos. Consequentemente, os Operadores de Telecomunicações devem preparar a sua infraestrutura para o consumo futuro ao mesmo tempo que oferecem novos serviços para se manterem competitivos. Esta dissertação visa contribuir com conhecimento sobre quais alterações uma Operadora de Telecomunicações deve executar com o modelo de previsão de largura de banda proposto. Os resultados obtidos abriram caminho para o método de entrega de conteúdos multimedia proposto, que visa ao melhoramento da qualidade de experiência do utilizador ao mesmo tempo que se optimiza o processo de balanceamento de carga. No geral os testes confirmam uma melhoria na qualidade de experiência do utilizador usando o método proposto.Mestrado em Engenharia de Computadores e Telemátic

    Video Quality Assessment in Video Streaming Services:Encoder Performance Comparison

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    Serviços OTT TV: aspectos técnico-económicos

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    Mestrado em Engenharia Eletrónica e TelecomunicaçõesThe breadth of availability and variety of online video contents has helped to encourage a far more mobile experience, which has proved particularly popular among younger generations. Over The Top (OTT) services, particularly those on-demand video platforms, became more and more attractive to consumers when compared with the current main TV packages. This document describes how the video OTT Ecosystem works from a technical side. The description presented reaches both ends of the distribution chain: from how the video signals are acquired and processed, thru all the way to how they are delivered to the client, passing by the challenges and consequences that such services have on the network. The main objective of this dissertation is to understand the possibility to create in Portugal a new operator where the core business is video delivery using only OTT services.A amplitude e variedade de conteúdos disponíveis online têm ajudado a promover uma experiência cada ver mais móvel da televisão, serviço que se tem revelado particularmente popular entre os mais jovens. Serviços Over The Top (OTT), sobretudo aqueles disponíveis através de plataformas de video on-demand, têm-se tornado cada vez mais atraentes para os consumidores, em comparação com os atuais pacotes de televisão. Este documento descreve como funciona, do ponto de vista técnico, o ecossistema do vídeo sobre OTT. A descrição apresentada abrange ambas as extremidades da cadeia de distribuição: desde a forma como os sinais de vídeo são adquiridos e processados até ao modo como eles são entregues ao cliente, passando pelos problemas e consequências que tais serviços podem ter na rede. O principal objectivo deste trabalho é contribuir para compreender se é possível criar em Portugal um novo operador onde o core business seja a distribuição de vídeo utilizando apenas serviços OTT

    Structural Separation and Prospects for Welfare-Enhancing Price Discrimination in a New 'Natural Monopoly' Network: comparing fibre broadband proposals in Australia and New Zealand

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    The Australian and New Zealand governments have both decided that substantial government investment is required to accelerate the deployment of new nationwide fibre-to-the-home (FTTH) networks. This paper examines the two proposals in light of the crucial role of price discrimination in enabling rapid and early uptake of a new technology with a natural monopoly cost structure given the assumptions that both networks will be subject to provisions that separate elements of network ownership from retail operations and both will face competition from other (vertically integrated) network technologies. Whilst price discrimination enables a monopolist to maximise profits by extracting surplus from consumers when the firm has a natural monopoly cost structure it also enables the firm to increase welfare by accessing scale economies (static efficiency gains) and to introduce the technology earlier than under the counterfactual of a single price (dynamic efficiency gains). However vertical separation of network and retail functions and regulated 'open access' and 'equivalence' requirements used as regulatory tools to increase retail competition and constrain price and non-price discrimination by monopoly network operators restricts the ability of a new network operator to use its price structure to introduce the technology in a timely manner and to gain access to welfare-enhancing scale economies. In a competitive environment when the new (frontier) network must build its customer base principally from the substitution of customers from the existing (legacy) natural monopoly networks (which may be vertically integrated and engaging in price discrimination themselves) the non-discriminatory provisions of structural separation impose substantial limitations upon the regulated firm's business case. Both the Australian and New Zealand FTTH proposal impose separation and non-discrimination requirements as a precondition for government financing although they differ in their approaches in respect of both the point at which the separation must be enforced and the extent of competition anticipated from existing network operators. Whilst neither proposal enables the full efficiency gains available from producing at maximum efficient scale to be realised the Australian proposal with integration of layer 1 and 2 operators and acquisition of the competing copper access networks appears to offer efficiency and substitution advantages over the New Zealand proposal which requires separation between layer 1 and 2 operators and provides no clear view of the competitive positioning of the FTTH network relative to the legacy copper access rival

    Broadband market in South Korea

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