8 research outputs found

    Validation of "triple-play" services in the access node

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    Mestrado em Engenharia Electrónica e TelecomunicaçõesCom o grande crescimento das comunicações fixas, as tecnologias de fornecimento de acesso à Internet, como o cabo (CATV) e o par de cobre (xDSL), têm possibilitado o fornecimento de serviços adicionais para além do típico acesso à Internet de Banda Larga (em que, desde há vários anos o serviço de televisão já existe na tecnologia de cabo). Assim sendo, e ainda devido a uma forte concorrência entre operadores de cabo e de “cobre”, o DSL Forum apresenta uma solução de arquitectura da rede de acesso e agregação que permite a migração da tradicional tecnologia ATM para Ethernet, em tecnologias baseadas em xDSL. A migração da arquitectura para uma rede baseada em Ethernet permite o fornecimento de serviços adicionais que exijam altos débitos, qualidade de serviço, transmissão de multicast, VOIP, entre outros. A presente tese apresenta os requisitos propostos pelo DSL Forum para o equipamento da rede de acesso e agregação: o nó de acesso (DSLAM), e um conjunto de testes conducentes à validação dos mesmos em laboratório, simulando uma possível rede de fornecedor de serviços. ABSTRACT: With the large growth of fixed communications, the technology that provides Internet access, such as cable (CATV) and copper (xDSL), need to enable the provision of additional services beyond the typical broadband Internet access (where, television service already exists for several years over cable technology). Thus, because of strong competition between cable and copper operators , DSL Forum presents an architecture and aggregation solution for the xDSL based access networks that allows the migration of traditional ATM technology to Ethernet. The migration of the architecture to Ethernet based network is due to the high speeds offer, and the possibility of additional services supporting quality of service, multicast transmission, VOIP, amongst others. This thesis presents the requirements proposed by the DSL Forum for the equipment of the access network and aggregation: access node (DSLAM), and their validation in a laboratory environment, simulating service provision scenarios

    Aperfeiçoamento do desempenho do TCP em links assimétricos via políticas de escalonamento de filas

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    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.O objetivo deste trabalho é apresentar uma proposta de melhoria a problemas de desempenho do TCP, que ocorrem devido aos efeitos da assimetria. Estes problemas acontecem em redes de acesso assimétricas, causando degradação no desempenho final do TCP, os quais ocorrem devido as imperfeições e variações no retorno dos pacotes de confirmação, Acknowlegement, enviados pela estação cliente em resposta aos pacotes de dados recebidos da estação servidora. Este trabalho detalha algumas soluções a este problema, os quais usam técnicas locais de camada de rede. Como resultado de nossa pesquisa apresentamos uma proposta baseada no aperfeiçoamento e combinação de algumas destas técnicas, e cujos resultados obtidos analisamos através de simulação de modelos

    Optimization and Performance Analysis of High Speed Mobile Access Networks

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    The end-to-end performance evaluation of high speed broadband mobile access networks is the main focus of this work. Novel transport network adaptive flow control and enhanced congestion control algorithms are proposed, implemented, tested and validated using a comprehensive High speed packet Access (HSPA) system simulator. The simulation analysis confirms that the aforementioned algorithms are able to provide reliable and guaranteed services for both network operators and end users cost-effectively. Further, two novel analytical models one for congestion control and the other for the combined flow control and congestion control which are based on Markov chains are designed and developed to perform the aforementioned analysis efficiently compared to time consuming detailed system simulations. In addition, the effects of the Long Term Evolution (LTE) transport network (S1and X2 interfaces) on the end user performance are investigated and analysed by introducing a novel comprehensive MAC scheduling scheme and a novel transport service differentiation model

    Розробка та реалізація мережних протоколів. Навчальний посібник

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    Розробка та реалізація мережних протоколів важлива частина сучасної галузі знань, що необхідна для актуального забезпечення взаємозв’язку рівнів та різних технологій будь-якої локальної і глобальної мереж. Мережеві протоколи базуються на міжнародних стандартах, що забезпечують якісну взаємодію різних інноваційних технологій та різних елементів мережі. Вони складають семирівневу структуру, яка здійснює забезпечення вирішення інженерно-технічних питань та потребує постійно оновлювати, вдосконалювати та розробки нових протоколів, як правила взаємодії всіх складових глобальної мережі. Розробка та реалізація мережних протоколів потребує постійного розвитку та вдосконалення для надання абонентам високонадійних видів послуг з високошвидкісною передачею даних.The development and implementation of network protocols is an important part of the modern field of knowledge that is necessary for the actual interconnection of levels and different technologies of any local and global networks. Network protocols are based on international standards that ensure high-quality interaction of various innovative technologies and various network elements. They form a seven-tier structure that provides solutions to engineering and technical issues and requires constant updating, improvement and development of new protocols, as rules of interaction of all components of the global network. The development and implementation of network protocols requires constant development and improvement to provide subscribers with highly reliable types of services with high-speed data transmission.Разработка и реализация сетевых протоколов важная часть современной отрасли знаний, которая необходима для актуального обеспечения взаимосвязи уровней и различных технологий любой локальной и глобальной сетей. Сетевые протоколы базируются на международных стандартах, обеспечивающих качественное взаимодействие различных инновационных технологий и различных элементов сети. Они составляют семиступенчатая структуру, которая осуществляет обеспечение решения инженерно-технических вопросов и требует постоянно обновлять, совершенствовать и разрабатывать новые протоколы, как правила взаимодействия всех составляющих глобальной сети. Разработка и реализация сетевых протоколов требует постоянного развития и совершенствования для предоставления абонентам высоконадежных видов услуг по высокоскоростной передачей данных

    Schemes for building an efficient all-optical virtual private network.

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    by Tam Scott Kin Lun.Thesis submitted in: October 2005.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references (leaves 58-64).Abstracts in English and Chinese.Chapter 1. --- Introduction --- p.1Chapter 1.1. --- Optical Networks --- p.1Chapter 1.1.1. --- IP over Optical Networks --- p.1Chapter 1.1.2. --- Challenges in Optical Networks --- p.4Chapter 1.2. --- Virtual Private Networks (VPN) --- p.5Chapter 1.2.1. --- CE Based VPN --- p.6Chapter 1.2.2. --- Network Based VPN --- p.7Chapter 1.2.2.1. --- MPLS Layer 2 VPN --- p.8Chapter 1.2.2.2. --- MPLS Layer 3 VPN --- p.9Chapter 1.2.3. --- Optical VPN --- p.9Chapter 1.2.4. --- Challenges in VPN Technologies --- p.11Chapter 1.3. --- Objective of this Thesis --- p.11Chapter 1.4. --- Outline of this Thesis --- p.12Chapter 2. --- Architecture of an All-Optical VPN --- p.13Chapter 2.1. --- Introduction --- p.13Chapter 2.2. --- Networking Vendor Activities --- p.13Chapter 2.3. --- Service Provider Activities --- p.15Chapter 2.4. --- Standard Bodies Activities --- p.16Chapter 2.5. --- Requirements for All-Optical VPN --- p.17Chapter 2.6. --- Reconfigurability of an All-Optical VPN --- p.19Chapter 2.7. --- Switching Methods in All-Optical VPN --- p.20Chapter 2.8. --- Survivability of an All-Optical VPN --- p.23Chapter 3. --- Maximizing the Utilization Of A Survivable Multi-Ring WDM Network --- p.25Chapter 3.1. --- Introduction --- p.25Chapter 3.2. --- Background --- p.25Chapter 3.3. --- Method --- p.26Chapter 3.3.1. --- Effect on packet based services --- p.28Chapter 3.3.2. --- Effect on optical circuit based services --- p.28Chapter 3.4. --- Simulation results --- p.29Chapter 3.5. --- Chapter Summary --- p.36Chapter 4. --- Design of an All-Optical VPN Processing Engine --- p.37Chapter 4.1. --- Introduction --- p.37Chapter 4.2. --- Concepts of Optical Processors --- p.38Chapter 4.3. --- Design Principles of the All-Optical VPN Processing Engine --- p.40Chapter 4.3.1. --- Systolic System --- p.41Chapter 4.3.2. --- Design Considerations of an Optical Processing Cell --- p.42Chapter 4.3.2.1. --- Mach-Zehnder Structures --- p.43Chapter 4.3.2.2. --- Vertical Cavity Semiconductor Optical Amplifier --- p.43Chapter 4.3.2.3. --- The Optical Processing Cell --- p.44Chapter 4.3.3. --- All-Optical VPN Processing Engine --- p.47Chapter 4.4. --- Design Evaluation --- p.49Chapter 4.5. --- Application Example --- p.50Chapter 4.6. --- Chapter Summary --- p.54Chapter 5. --- Conclusion --- p.55Chapter 5.1. --- Summary of the Thesis --- p.55Chapter 5.2. --- Future Works --- p.56Chapter 6. --- References --- p.5

    Layer Two Tunnelling Protocol (L2TP) Over ATM Adaptation Layer 5 (AAL5)

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    Tecnología de las comunicaciones móviles

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    Las comunicaciones móviles es, claramente, uno de los campos de las telecomunicaciones donde estamos viviendo, día a día, un mayor desarrollo y cambio. El Área de Teoría de la Señal y Comunicaciones de la Universidad Miguel Hernández no se puede mostrar insensible a tales acontecimientos, y prueba de ello es la presente publicación. Con ella se pretende ofrecer al lector una completa visión de diferentes aspectos, como puede comprobar consultando el índice de la misma. Pretende ser un buen complemento a las explicaciones de clase de la asignatura “Tecnología de las comunicaciones móviles”, para la que está especialmente ideado. Se ha tratado de completar el libro “Introducción a las comunicaciones móviles” con las tecnologías de las comunicaciones móviles optimizadas para datos, y por tanto, orientadas a conmutación de paquetes. En el primer capítulo se da una breve introducción a WAP, pasando, después, en el capítulo 2 a describir más en profundidad GPRS o generación 2,5 de la telefonía móvil en Europa. El capítulo 3, nos introduce en la técnica de acceso múltiple por división de código, CDMA, para facilitarnos la mejor comprensión de los capítulos siguientes. En UMTS o tercera generación, (capítulo 4) nos paramos con más detalle, por ser la tecnología que se pretende revolucione el futuro. Por último, los capítulos 5 y 6 dan una iniciación a otras tecnologías, que aunque con cierta incertidumbre, interactuarán con las redes móviles en el entorno privado, como son las redes inalámbricas, WLAN, y Bluetooth
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