• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 15
  • 6
  • 5
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 43
  • 15
  • 13
  • 13
  • 13
  • 10
  • 8
  • 8
  • 7
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A SECURE MEDIA STREAM COMMUNICATION FOR NEXT GENERATION NETWORK

Wu, Hao, Zhong, Zhangdui 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / In NGN, the open interfaces and the IP protocol make the hazard of security aspect increased accordingly. Thereby, it is a very important premise for NGN network operation to afford a good secure media stream communication. In this paper, we will present a secure media stream communication for NGN. Then we will discuss the three parts of the media stream secure communication——media stream source authentication, secret key negotiation and distribution; media stream encryption/decryption in detail. It can effectively realize media stream end-to-end secure communication. Meanwhile, it also makes use of the expanding of former protocol during the secret key negotiation process.
2

Quality of Service optimisation framework for Next Generation Networks

Weber, Frank Gerd January 2012 (has links)
Within recent years, the concept of Next Generation Networks (NGN) has become widely accepted within the telecommunication area, in parallel with the migration of telecommunication networks from traditional circuit-switched technologies such as ISDN (Integrated Services Digital Network) towards packet-switched NGN. In this context, SIP (Session Initiation Protocol), originally developed for Internet use only, has emerged as the major signalling protocol for multimedia sessions in IP (Internet Protocol) based NGN. One of the traditional limitations of IP when faced with the challenges of real-time communications is the lack of quality support at the network layer. In line with NGN specification work, international standardisation bodies have defined a sophisticated QoS (Quality of Service) architecture for NGN, controlling IP transport resources and conventional IP QoS mechanisms through centralised higher layer network elements via cross-layer signalling. Being able to centrally control QoS conditions for any media session in NGN without the imperative of a cross-layer approach would result in a feasible and less complex NGN architecture. Especially the demand for additional network elements would be decreased, resulting in the reduction of system and operational costs in both, service and transport infrastructure. This thesis proposes a novel framework for QoS optimisation for media sessions in SIP-based NGN without the need for cross-layer signalling. One key contribution of the framework is the approach to identify and logically group media sessions that encounter similar QoS conditions, which is performed by applying pattern recognition and clustering techniques. Based on this novel methodology, the framework provides functions and mechanisms for comprehensive resource-saving QoS estimation, adaptation of QoS conditions, and support of Call Admission Control. The framework can be integrated with any arbitrary SIP-IP-based real-time communication infrastructure, since it does not require access to any particular QoS control or monitoring functionalities provided within the IP transport network. The proposed framework concept has been deployed and validated in a prototypical simulation environment. Simulation results show MOS (Mean Opinion Score) improvement rates between 53 and 66 percent without any active control of transport network resources. Overall, the proposed framework comes as an effective concept for central controlled QoS optimisation in NGN without the need for cross-layer signalling. As such, by either being run stand-alone or combined with conventional QoS control mechanisms, the framework provides a comprehensive basis for both the reduction of complexity and mitigation of issues coming along with QoS provision in NGN.
3

User-centric quality of service provisioning in IP networks

Culverhouse, Mark January 2012 (has links)
The Internet has become the preferred transport medium for almost every type of communication, continuing to grow, both in terms of the number of users and delivered services. Efforts have been made to ensure that time sensitive applications receive sufficient resources and subsequently receive an acceptable Quality of Service (QoS). However, typical Internet users no longer use a single service at a given point in time, as they are instead engaged in a multimedia-rich experience, comprising of many different concurrent services. Given the scalability problems raised by the diversity of the users and traffic, in conjunction with their increasing expectations, the task of QoS provisioning can no longer be approached from the perspective of providing priority to specific traffic types over coexisting services; either through explicit resource reservation, or traffic classification using static policies, as is the case with the current approach to QoS provisioning, Differentiated Services (Diffserv). This current use of static resource allocation and traffic shaping methods reveals a distinct lack of synergy between current QoS practices and user activities, thus highlighting a need for a QoS solution reflecting the user services. The aim of this thesis is to investigate and propose a novel QoS architecture, which considers the activities of the user and manages resources from a user-centric perspective. The research begins with a comprehensive examination of existing QoS technologies and mechanisms, arguing that current QoS practises are too static in their configuration and typically give priority to specific individual services rather than considering the user experience. The analysis also reveals the potential threat that unresponsive application traffic presents to coexisting Internet services and QoS efforts, and introduces the requirement for a balance between application QoS and fairness. This thesis proposes a novel architecture, the Congestion Aware Packet Scheduler (CAPS), which manages and controls traffic at the point of service aggregation, in order to optimise the overall QoS of the user experience. The CAPS architecture, in contrast to traditional QoS alternatives, places no predetermined precedence on a specific traffic; instead, it adapts QoS policies to each individual’s Internet traffic profile and dynamically controls the ratio of user services to maintain an optimised QoS experience. The rationale behind this approach was to enable a QoS optimised experience to each Internet user and not just those using preferred services. Furthermore, unresponsive bandwidth intensive applications, such as Peer-to-Peer, are managed fairly while minimising their impact on coexisting services. The CAPS architecture has been validated through extensive simulations with the topologies used replicating the complexity and scale of real-network ISP infrastructures. The results show that for a number of different user-traffic profiles, the proposed approach achieves an improved aggregate QoS for each user when compared with Best effort Internet, Traditional Diffserv and Weighted-RED configurations. Furthermore, the results demonstrate that the proposed architecture not only provides an optimised QoS to the user, irrespective of their traffic profile, but through the avoidance of static resource allocation, can adapt with the Internet user as their use of services change.
4

A Study of Performance Appraisal of Next Generation Networks Programs

Liu, Hao-ming 03 July 2008 (has links)
Since 1999, Ministry of Economic Affairs, R.O.C. boosts ITDP programs actively¡Adeveloping science and technology programs get more and more important for upgrading industry¡¦s R&D abilities. This study is going to establish a performance appraisal model to promote the justice and trust of programs appraisal, provide government for a well model to advance national industries¡¦ forces and competencies. This study establishes a performance appraisal model with AHP and Delphi method. It is shown that ¡§networks effect¡¨ is the most important and critical index of this model and program. Finally we address a performance appraisal model to help the government and industries set up an evaluation or execute appraisal strategy well.
5

Estudio de Arquitecturas para la Convergencia de Telefonía Fija-Móvil

Peña Zamudio, Paulina Natalia January 2007 (has links)
El acelerado desarrollo de las tecnologías en telecomunicaciones tanto de telefonía fija y móvil como de las redes de datos, junto con el surgimiento de nuevas tecnologías de acceso para proveer distintos servicios han abierto las puertas a nuevos problemas y oportunidades a las empresas. Mientras por un lado, la amplia gama de tecnologías ha permitido un mayor número de servicios y de penetración en los distintos estratos y nichos de usuarios, por otro lado, la interoperabilidad entre distintas redes se ha vuelto un problema no menor. Desde hace algún tiempo se están viviendo una serie de cambios dentro de las redes de los operadores de telecomunicaciones: ya no basta que una empresa de telefonía ofrezca sólo servicios de telefonía e Internet, o que las empresas distribuidoras de televisión por cable ofrezcan sólo servicios de televisión, sino que todas las redes de telecomunicaciones se están orientando y evolucionando a brindar un amplio espectro de servicios. Este fenómeno se conoce como convergencia de redes o FMC (Fixed Mobile Convergence). El concepto de convergencia fija-móvil se enfoca a la provisión de servicios desde cualquier tipo de terminal y sin importar la red de acceso utilizada. Para eso es necesario hacer que todos los tipos de redes de telecomunicaciones interactúen entre sí, de forma de orientarlas a los servicios y aplicaciones sin importar la naturaleza del acceso utilizado por el usuario. Surgen así conceptos como el de NGN (Next Generation Network) para lograr este objetivo y nuevas arquitecturas integradoras como lo son IMS (IP Multimedia Subsystem). En este trabajo se presenta un estudio de las principales arquitecturas actuales de telefonía tanto fijas como móviles, donde se contempla la telefonía fija tradicional, celular e IP. Dentro de este estudio se examinan sus componentes funcionales, protocolos e interfaces con la finalidad de plantear y estudiar las arquitecturas y componentes necesarias para que estas redes sean interoperables, planteando una arquitectura convergente y orientada a servicios. Se expone como resultado principalmente un estudio de la arquitectura IMS como una opción factible para lograr la convergencia, mostrando sus principales entidades y procedimientos de interoperación con otras redes. Además, como un aporte a las tecnologías de acceso inalámbricas emergentes en servicios de redes se plantea una arquitectura con WiMAX como tecnología de acceso y se comparan sus ventajas y desventajas en relación a otras tecnologías de acceso a las redes de telecomunicaciones. La descripción detallada tanto de las componentes de IMS como paraguas de la convergencia como de los procedimientos de interoperación entre esta arquitectura y diferentes redes de acceso da pie para el desarrollo de nuevas memorias relativas a este tema, como por ejemplo la implementación de una arquitectura convergente a nivel docente basada en IMS utilizando tecnologías de acceso de interés en la actualidad, como lo son las tecnologías inalámbricas y en particular WiMAX. Las futuras investigaciones y trabajos de desarrollo basados en la convergencia de redes son de gran importancia en la formación de ingenieros útiles y valiosos para el mercado de hoy en día.
6

On privacy in mobile voice communication networks

Croft, Neil John 03 October 2011 (has links)
The introduction of mobile communications has undoubtedly altered our physical and social world. Like the Internet, it has changed the way we interact with each other allowing for communication using a variety of communication mediums by means of a magnitude of interactive mobile devices. The context, content, persons communicating, situation and timing all have a varying degree of influence on the sensitivity of information being shared. The individual's awareness of exposure of their private information on the Internet has filtered through into the mobile communications space. It is commonly held in current mobile communication network literature that as privacy-sensitive information travels through a network, it may be exposed to privacy infringement at various stages along its journey. Much of the concern from the individual's perspective, though, stems from a fear of the unknown. In the presence of these threats and vulnerabilities it is justified to wonder whether current mobile communications networks (and indeed future networks) provides sufficient privacy for users with very valuable information to communicate. In this thesis, I develop a systematic approach to identifying areas of privacy concern in a current mobile communication networks in an effort to outline mobile communication privacy principles and how applicable they are in Next Generation Networks. With a privacy stance, the objective of my work is through technical examination and sometimes theoretical undertaking to identify acceptable solutions which restrict the flow of private information and ultimately confirm, through privacy analyses, the benefits gained in doing so. The results show that, given the current situation and technological configuration, there are commonalities which extend beyond a mere concern within a mobile communications network's requirement for privacy enhancement. In a perfect world, the idea is to articulate towards a system of privacy by design rather than as an uttered afterthought. It is no longer inconceivable to think there is an opportunity to deliver a privacy-conscious network, if careful consideration is given to all parties and aspects that govern a mobile communications network and the correct privacy-enhancing technologies are administered correctly. Throughout my thesis, although each privacy solution is segmented and may have a specific privacy application, the results attested contribute largely to a converged prospectus for privacy-aware future generation communication networks. The significance of this lies in the study of past privacy pitfalls in order to better manage the potential for future privacy problems. The rationalisation is if privacy principles are identified (in existing networks) and adhered and applied to (in next generation networks), then we converge towards a network infrastructure that possesses a desirable level of privacy protection. / Thesis (PhD)--University of Pretoria, 2011. / Computer Science / unrestricted
7

An IMS-based VOD Service Supporting Session Continuation

Johansson, Jonatan January 2009 (has links)
<p>IP-based TV (IPTV) is gradually replacing traditional means for broadcasting. At the same time, players from the telecom industry is seeking to create a new, standardized architectural framework for delivering all kinds of multimedia services over IP to end users; the IP Multimedia Subsystem (IMS).</p><p>This thesis is about video on demand, one of the more popular services enabled by IPTV. The thesis starts out by introducing the reader to IMS and IPTV and presents the current work in the area of IMS-based IPTV, done by the TISPAN committee of the ETSI.</p><p>The author then takes an explorative approach in investigating how a signaling schema for an IMS-based VOD service could look like, based on TISPAN’s existing work. The service is subject to an extra requirement; it should support session continuity, meaning it should be possible to resume the streaming of a video where the user left off, possibly on a different device. The investigation shows that it is possible to combine SIP and RTSP in several ways to get the desired behaviour.</p><p>The second part of the results consists of a proof of technology-implementation of the signaling schema that is the output from the first part. The implemented service runs on an IPTV set-top box on the client side, and a regular PC on the server side. The service uses open source software to a great extent and is fairly portable. A sample VOD session using the implemented system is presented along with full message contents.</p><p>The thesis concludes with a summary of the results and a discussion on what has been left out from the implementation and possibly subject to further studies. Finally, there is a brief summary on the recent developments within the field of IMS-based IPTV.</p>
8

An IMS-based VOD Service Supporting Session Continuation

Johansson, Jonatan January 2009 (has links)
IP-based TV (IPTV) is gradually replacing traditional means for broadcasting. At the same time, players from the telecom industry is seeking to create a new, standardized architectural framework for delivering all kinds of multimedia services over IP to end users; the IP Multimedia Subsystem (IMS). This thesis is about video on demand, one of the more popular services enabled by IPTV. The thesis starts out by introducing the reader to IMS and IPTV and presents the current work in the area of IMS-based IPTV, done by the TISPAN committee of the ETSI. The author then takes an explorative approach in investigating how a signaling schema for an IMS-based VOD service could look like, based on TISPAN’s existing work. The service is subject to an extra requirement; it should support session continuity, meaning it should be possible to resume the streaming of a video where the user left off, possibly on a different device. The investigation shows that it is possible to combine SIP and RTSP in several ways to get the desired behaviour. The second part of the results consists of a proof of technology-implementation of the signaling schema that is the output from the first part. The implemented service runs on an IPTV set-top box on the client side, and a regular PC on the server side. The service uses open source software to a great extent and is fairly portable. A sample VOD session using the implemented system is presented along with full message contents. The thesis concludes with a summary of the results and a discussion on what has been left out from the implementation and possibly subject to further studies. Finally, there is a brief summary on the recent developments within the field of IMS-based IPTV.
9

La sécurité des futures architectures convergentes pour des services personnalisés : aspect architectural et protocolaire / Security of converging future architectures for personalized services : architectural and protocol aspects

Hammami, Ali 01 July 2013 (has links)
L’émergence et l’évolution des réseaux de nouvelles génération (NGN) a soulevé plusieurs défis surtout en termes d’hétérogénéité, de mobilité et de sécurité. En effet, l’utilisateur est capable, dans un tel environnement, d’avoir accès à plusieurs réseaux, à travers différents terminaux, avec un choix vaste de services fournis par différents fournisseurs. De plus, les utilisateurs finaux demandent à être constamment connectés n’importe où, n’importe quand et n’importe comment. Ils désirent également avoir un accès sécurisé à leurs services à travers une session dynamique, seamless et continue selon leurs préférences et la QoS demandée. Dans ce contexte, la sécurité représente une composante majeure. Face à cette session user-centric sécurisée, plusieurs défis se posent. L’environnement est de plus en plus ouvert, de multiples services ne sont pas connus d’avance et nous avons une diversité de communications entre les services et les utilisateurs. L’hétérogénéité des ressources (terminaux, réseaux et services) impliquées dans la session de l’utilisateur accentue la complexité des tâches de sécurité. Les différentes déclinaisons de mobilité (mobilité de l’utilisateur, mobilité du terminal, mobilité du réseau et mobilité du service) modifient la session user-centric que l’on veut unique, sécurisée et seamless avec la délivrance d’un service continu. / The emergence and evolution of Next Generation Networks (NGN) have raised several challenges mainly in terms of heterogeneity, mobility and security. In fact, the user is able, in such environment, to have access to many networks, via multiple devices, with a vast choice of services offered by different providers. Furthermore, end-users claim to be constantly connected anywhere, anytime and anyhow. Besides, they want to have a secure access to their services through a dynamic, seamless and continuous session according to their preferences and the desired QoS. In this context, security represents an important concern. In fact, this user-centric session should obviously be secured. However, many challenges arise. In such environment, system boundaries, which were well delimited, become increasingly open. Indeed, there are multiple services which are unknown in advance and multiple communications between services and with users. Besides, heterogeneity of involved resources (terminals, networks and services) in the user session increases the complexity of security tasks. In addition, the different types of mobility (user, terminal, network and service mobility) affect the user-centric session that should be unique, secure and seamless and ensure continuity of services.
10

Acessos sob demanda em NGN: impactos das trocas dinâmicas entre provedores Wi-Fi para o usuário móvel / Access on demand in NGN: the impact of dynamic switching of Wi-Fi

Augusto, Mario Ezequiel 12 November 2012 (has links)
Atualmente tem crescido o uso de aparelhos móveis com mais de uma interface de rede para o acesso à Internet, caracterizando em parte as Redes de Próxima Geração (NGN). Outras características da NGN são o acesso sob demanda, no qual o cliente de acesso não seria, necessariamente, usuário de um único provedor e usaria a rede de outros provedores conforme a necessidade, e o gerenciamento de handover (trocas de rede) centrado no usuário, no qual o usuário é quem decide à qual rede vai se conectar e em que momento. Existem algumas implicações relacionadas ao acesso sob demanda que podem melhorar ou piorar a experiência de acesso do usuário e causar certos impactos relacionados à vazão recebida, valor gasto, número de handovers, entre outros. Para o dispositivo móvel gerenciar os handovers, ele precisa obter informações sobre as redes disponíveis como, por exemplo, preço e incentivos, além das informações já obtidas atualmente como força do sinal recebido e identificador do provedor (SSID). Porém, os provedores não possuem um sistema automatizado para fornecer tais informações aos dispositivos móveis. Esta tese apresenta uma avaliação dos impactos das trocas dinâmicas entre provedores Wi-Fi para o usuário móvel, comparando o acesso sob demanda com o acesso tradicional (como é feito atualmente). Como metodologia para esta avaliação, foram realizadas simulações de redes em um cenário com provedores Wi-Fi com perfis diferentes, nas quais foram analisados o número de handovers realizados, a quantidade de bytes recebidos e o valor gasto com o acesso. Nestas simulações o usuário pôde priorizar o custo da conexão, a força do sinal recebido e a carga de trabalho no ponto de acesso para decidir a troca de rede. Esta tese também apresenta uma arquitetura para provimento de informações adicionais sobre as redes disponíveis em um ambiente de acesso sob demanda com gerenciamento de handover centrado no usuário, chamada MYHand (MIH-based and Y-Comm-based Handover Management). Para isso foi utilizada a arquitetura para acesso sob demanda chamada Y-Comm e o padrão IEEE 802.21 (MIH Media Independent Handover). Os resultados desta tese contribuem no gerenciamento das trocas de rede e ubiquidade do acesso à Internet em NGN. A arquitetura MYHand auxiliará o dispositivo móvel a obter mais informações necessárias à decisão de handover, podendo otimizá-la. Com os resultados das simulações, o dispositivo móvel poderá prever o quanto determinada decisão poderá beneficiar a experiência do usuário em termos de qualidade da conexão e custo / Currently, the usage of mobile devices with multiple network interfaces for Internet access has been growing, characterizing partially the Next Generation Networks (NGN). Other features of the NGN are access on demand, in which the customer is not, necessarily, user of a single provider and would use the network of other providers as needed, and the user-centric handover management, in which the user decides which network to connect to and at which time. There are some implications related to access on demand which can improve or worsen the user access experience and cause some impacts related to throughput, paid value, number of handovers, among others. The mobile can manage the handovers but he needs to obtain information about available networks as, for example, price and incentives, in addition to the information already obtained currently as received signal strength and provider identifier (SSID). However, providers do not have an automated system to provide such information to mobile devices. This thesis presents an evaluation of the impacts of dynamic switching between Wi-Fi providers for the mobile user, comparing access on demand to the traditional approach (as currently done). As methodology for this evaluation, simulations were performed in a scenario with Wi-Fi providers with different profiles, in which the number of handovers performed, the amount of received bytes, and the paid value were analyzed. In these simulations the mobile user could prioritize the cost of the connection, the received signal strength, and the load on the access point to decide the handover. This thesis also presents an architecture for additional information provisioning about available networks in an access on demand environment with user-centric handover management, called MYHand (MIH-based and Y-Comm-based Handover Management). For this purpose, an architecture for access on demand called Y-Comm and the IEEE 802.21 standard (MIH Media Independent Handover) were used. The results of this thesis contribute to the handover management and ubiquity of Internet access in NGN. The MYHand architecture will assist the mobile device to obtain more information, necessary to the handover decision, optimizing it. With the results of the simulations, the mobile device can predict how much a particular decision may benefit the user experience in terms of connection quality and cost

Page generated in 0.0265 seconds