513 research outputs found

    Multicast Mobility in Mobile IP Version 6 (MIPv6) : Problem Statement and Brief Survey

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    Mobility through Heterogeneous Networks in a 4G Environment

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    Serving and Managing users in a heterogeneous environment. 17th WWRF Meeting in Heidelberg, Germany, 15 - 17 November 2006. [Proceeding presented at WG3 - Co-operative and Ad-hoc Networks]The increase will of ubiquitous access of the users to the requested services points towards the integration of heterogeneous networks. In this sense, a user shall be able to access its services through different access technologies, such as WLAN, Wimax, UMTS and DVB technologies, from the same or different network operators, and to seamless move between different networks with active communications. In this paper we propose a mobility architecture able to support this users’ ubiquitous access and seamless movement, while simultaneously bringing a large flexibility to access network operators

    Key distribution technique for IPTV services with support for admission control and user defined groups

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    Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

    A Cross-System Approach for Multimedia Services with IP Multicast in 4G Networks

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    The increased demand for multimedia services by mobile end users in recent years have driven both Broadcast and Wireless Network operators to develop new systems and architectures for the deployment of such services. The proposed solutions are nonetheless limited either in terms of QoS or Capabilities to deliver new interactive services. This paper highlights strengths and drawbacks of the existing technologies in terms of QoS, Security and Mobility. In order to fill the gap between current solutions we propose a new architecture that builds itself on the synergies created by a heterogeneous network made of existing delivering technologies, such as 3GPP/MBMS and DVB, where services can be delivered to end-users in the most appropriate way for end-users and operators alike. A prototype implementation is further described.EU project - IST-2002- 506997 Daidalos I

    Architecture for satellite services over cryptographically heterogeneous networks with application into smart grid

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    The rapid growth in the demand for Future Internet services with many emerging group applications has driven the development of satellite, which is the preferred delivery mechanism due to its wide area coverage, multicasting capability and speed to deliver affordable future services. Nevertheless, security has been one of the obstacles for both satellite services as well as smart grid group applications, especially with logical/geographical/cryptographic domains spanning heterogeneous networks and regions. In this paper, adaptive security architecture is implemented to protect satellite services for smart grid group applications. The focus is on key management and policy provisioning. Leveraging Group Domain of Interpretation (GDOI) as the standard for smart grid centralized key/policy management architecture, a single Domain of Interpretation (DOI) is deployed and evaluated critically in terms of the added protocol signaling overhead on the satellite system for a fixed-network scenario. This also partially realizes the growing trend towards the use of TCP/IP technology for smart grid applications

    A Fair and Secure Cluster Formation Process for Ad Hoc Networks

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    An efficient approach for organizing large ad hoc networks is to divide the nodes into multiple clusters and designate, for each cluster, a clusterhead which is responsible for holding intercluster control information. The role of a clusterhead entails rights and duties. On the one hand, it has a dominant position in front of the others because it manages the connectivity and has access to other node¿s sensitive information. But on the other hand, the clusterhead role also has some associated costs. Hence, in order to prevent malicious nodes from taking control of the group in a fraudulent way and avoid selfish attacks from suitable nodes, the clusterhead needs to be elected in a secure way. In this paper we present a novel solution that guarantees the clusterhead is elected in a cheat-proof manner

    IPv6 Network Mobility

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    Network Authentication, Authorization, and Accounting has been used since before the days of the Internet as we know it today. Authentication asks the question, “Who or what are you?” Authorization asks, “What are you allowed to do?” And fi nally, accounting wants to know, “What did you do?” These fundamental security building blocks are being used in expanded ways today. The fi rst part of this two-part series focused on the overall concepts of AAA, the elements involved in AAA communications, and highlevel approaches to achieving specifi c AAA goals. It was published in IPJ Volume 10, No. 1[0]. This second part of the series discusses the protocols involved, specifi c applications of AAA, and considerations for the future of AAA

    Serviços multimédia multicast de próxima geração

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    Mestrado em Engenharia Electrónica e TelecomunicaçõesUma das mais recentes conquistas na evolução móvel foi o 3G, permitindo o acesso a serviços multimédia com qualidade de serviço assegurada. No entanto, a tecnologia UMTS, tal como definida na sua Release ’99, é apenas capaz de transmitir em modo unicast, sendo manifestamente ineficiente para comunicações multimédia almejando grupos de utilizadores. A tecnologia IMS surge na Release 5 do 3GPP que começou a responder já a algumas necessidades, permitindo comunicações sobre IP oferecendo serviços Internet a qualquer momento e em qualquer lugar sobre tecnologias de comunicação móveis fornecendo pela primeira vez sessões multimédia satisfatórias. A Release 6 por sua vez trouxe a tecnologia MBMS que permite transmissões em broadcast e multicast para redes móveis. O MBMS fornece os serviços de aplicações multimédia que todos estavam à espera, tanto para os utilizadores como para os prestadores de serviços. O operador pode agora fazer uso da tecnologia existente aumentando todo o tipo de benefícios no serviço prestado ao cliente. Com a possível integração destas duas tecnologias passa a ser possível desenvolver serviços assentes em redes convergentes em que os conteúdos são entregues usando tecnologias unicast, multicast ou broadcast. Neste contexto, o principal motivo deste trabalho consiste essencialmente em fazer uso dos recursos da rede terminando com o desperdício dos mesmos e aumentando a eficiência dos serviços através da integração das tecnologias IMS e MBMS. O trabalho realizado começa com o estudo do estado da arte das telecomunicações móveis com referência às tecnologias referidas, seguindo-se a apresentação da possível integração IMS-MBMS e terminando com o projecto de uma plataforma de demonstração que no futuro possa ser uma implementação de serviço multimédia multicast. O objectivo principal é mostrar os benefícios de um serviço que era normalmente executado em unicast relativamente ao modo multicast, fazendo uso da nova convergência de tecnologias IMS e MBMS. Na conclusão do trabalho são referidas as vantagens do uso de portadoras multicast e broadcast, tendo como perspectiva de que este trabalho possa ser um ponto de partida para um novo conjunto de serviços poupando recursos de rede e permitindo uma eficiência considerável em serviços inovadores.3G is bang up to date in the mobile phone industry. It allows access to multimedia services and gives a guarantee of quality of service. The UMTS technology, defined in 3GPP Release ’99, provides an unicast transmission, but it is completely inefficient when it comes to multimedia group communications. The IMS technology first appeared in Release 5 that has already started to consider the interests of the clients. It provides communications over IP, offering Internet services anytime, anywhere on mobile communication technologies. Also, it offers for the first time satisfactory multimedia sessions. On the other hand, Release 6 gave rise to the MBMS technology that provides broadcast and multicast transmissions for mobile networks. The MBMS provides multimedia applications services that everyone was waiting, including users and service providers. Now the operator makes use of existing technology in order to provide better costumer services. The possible integration of these two technologies will contribute to develop services based on converged networks in which contents are delivered through the unicast, multicast or broadcast technologies. Therefore, the objective of this work is basically to make use of network resources avoiding wastes and improving customer services through the integration of the IMS and the MBMS technologies. The executed work starts with the mobile telecommunications state of the art with reference to the referred technologies, followed by the IMS-MBMS convergence presentation and finishing with the proposal for implementation of a service platform that can be used for a multimedia multicast service. The main point is to show the benefits of a service that has been normally executed in unicast mode over the multicast mode, making use of the new IMS and MBMS technologies integration. To closure the work it is referred the advantages to use multicast and broadcast bearers, with the perspective that this work could be a starting point to a new set of services, saving network resources and allowing for innovate services a considerable efficency

    A wireless multicast delivery architecture for mobile terminals

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    Content delivery over the Internet to a large number of mobile users offers interesting business opportunities for content providers, intermediaries, and access network operators. A user could receive, for example, music or a digital newspaper directly to a mobile device over wireless networks. Currently, content delivery over the Internet is held back by a number of reasons. Existing network technologies, such as GPRS, have a very limited capacity to transfer large files, such as those required for good-quality pictures in a newspaper. Another problem is security. Content received over the Internet is very vulnerable to being forged. A user who cannot be certain about the source and consistency of the received stock quotes is unlikely to pay for the information. Furthermore, content providers are unwilling to distribute their valuable information over the Internet due to their fear of copyright infringements. Traditionally, content has been considered consumed as soon as it has been downloaded. Content providers have been keen on preventing their content from being transferred over peer-to-peer networks because they consider the delivery itself to be a copyright infringement. In this dissertation, content delivery is separated from content consumption by encrypting the content before delivery. When the users wishes to consume the content, a license which includes the decryption key is provided. The architecture allows content to be delivered to users' devices even before the user commits to consume the content. The user can choose to receive content whenever downloading it is the most convenient and affordable. Thus, the content providers are able to maintain control over the use of their information even after the data has been transferred to the users' terminals. In addition, content received by users can be strongly source authenticated. The architecture allows secure, efficient and reliable delivery of content to a large group of receivers. The architecture does not commit itself to any specific delivery technique, and the content can be delivered using any delivery technique including multicast, broadcast, unicast, and peer-to-peer. This dissertation focuses mostly on multicast as the delivery technique. The efficiency of the multicast delivery over unreliable heterogenous wireless access networks is thoroughly analyzed. Mobile terminals can seamlessly switch between access points and access technologies while continuing to receive data reliably from the network. The multicast delivery uses adaptive error correction and retransmissions to deliver the content as efficiently as possible to a very large number of receivers. The simulations show, that the vast majority of receivers are able to receive the content reliably with a small delay even when the radio network suffers from high packet loss probability. Although the architecture is designed to deliver content to mobile terminals, it is also suitable for delivering content to terminals with fixed Internet connectivity.Digitaalisen sisällön siirtäminen liikkuville käyttäjille Internetin yli tarjoaa uusia liiketoimintamahdollisuuksia niin sisällöntuottajille, välittäjille kuin verkko-operaattoreille. Teknikkaa voidaan käyttää esimerkiksi musiikin tai sähköisten lehtien välittämiseen käyttäjille langattoman verkon kautta. Sisällön välittämistä Internetin kautta hankaloittaa yhä usea seikka. Nykyisin laajassa käytössä olevat verkkotekniikat, kuten GPRS, ovat liian hitaita siirtämään hyvin suuria tiedostoja suurelle määrällä vastaanottajia. Lisäksi väärennetyn tiedon välittäminen Internetin kautta on erittäin helppoa. Sisältö, jonka aitoudesta ja alkuperästä ei ole varmuutta, on usein arvotonta käyttäjälle. Sisällöntuottajat puolestaan ovat haluttomia käyttämään sisältönsä levittämiseen Internetiä mikäli digitaalisesti levitettävän sisällön kopioiminen ja oikeudeton kuluttaminen on liian helppoa. Perinteisesti sisältö ajatellaankin kulutetuksi jo sillä hetkellä, kun se on siirretty käyttäjän laitteeseen. Sen vuoksi sisällön tuottajat ovatkin käyttäneet paljon resursejaan estääkseen sisältönsä välittämisen vertaisverkoissa, koska jo pelkkää sisällön siirtämistä pidetään tekijänoikeusrikkomuksena. Tässä työssä erotetaan sisällön siirtäminen sisällön kuluttamisesta suojaamalla sisältö salauksella ennen sen siirtämistä käyttäjille ja sallimalla vapaa salatun sisällön jakelu. Arkkitehtuuri mahdollistaa sisällön siirtämisen käyttäjien laitteille silloin kun sisällön siirtäminen on edullisinta ja tehokkainta. Vasta käyttäjän halutessa kuluttaa aiemmin lataamaansa sisältöä, tarkistetaan oikeis sisällön käyttöön. Arkkitehtuuri mahdollistaa myös ladatun sisällön alkuperän ja eheyden vahvan tarkistamisen. Arkkitehtuuri mahdollistaa turvallisen, tehokkaan ja luotettavan sisällön siirtämisen suurelle määrälle vastaanottajia. Arkkitehtuuri ei pakota sisällön jakelua käyttämään mitään tiettyä siirtomenetelmää vaan sisältö voidaan siirtää käyttäen esimerkiksi ryhmälähetystä (multicast), joukkolähetystä (broadcast), täsmälähetystä (unicast) tai vertaisverkkoja (peer-to-peer). Tässä työssä on keskitytty analysoimaan ryhmälähetyksen soveltuvuutta tiedon siirtomenetelmänä. Ryhmälähetysmenetelmän tehokkuutta on analysoitu siirrettäessä sisältöä heterogeenisen langattoman liityntäverkon yli. Liikkuvat päätelaitteet voivat siirtyä saumattomasti liityntäverkosta toiseen samalla kun ne vastaanottavat sisältöä. Ryhmälähetys hyödyntää adaptiivista virheenkorjausta ja uudelleenlähetyksiä siirtääkseen sisällönmahdollisimman tehokkaasti suurelle joukolle vastaanottajia. Simulaatiot osoittavat, että erittäin suuri osa vastaanottajista saa sisällön luotettavasti ja pienellä viiveellä vaikka liityntäverkossa pakettien virhetodennäköisyys olisi suuri. Arkkitehtuuri on suunniteltu siirtämään sisältöä liikkuville laitteille, mutta sitä voidaan käyttää yhtä hyvin myös kiinteään verkkoon liitettyjen laitteiden kanssa.reviewe
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