238 research outputs found
Performance Analysis of Multicast Mobility in a Hierarchical Mobile IP Proxy Environment
Mobility support in IPv6 networks is ready for release as an RFC, stimulating
major discussions on improvements to meet real-time communication requirements.
Sprawling hot spots of IP-only wireless networks at the same time await voice
and videoconferencing as standard mobile Internet services, thereby adding the
request for multicast support to real-time mobility. This paper briefly
introduces current approaches for seamless multicast extensions to Mobile IPv6.
Key issues of multicast mobility are discussed. Both analytically and in
simulations comparisons are drawn between handover performance characteristics,
dedicating special focus on the M-HMIPv6 approach.Comment: 11 pages, 7 figure
Roaming Real-Time Applications - Mobility Services in IPv6 Networks
Emerging mobility standards within the next generation Internet Protocol,
IPv6, promise to continuously operate devices roaming between IP networks.
Associated with the paradigm of ubiquitous computing and communication, network
technology is on the spot to deliver voice and videoconferencing as a standard
internet solution. However, current roaming procedures are too slow, to remain
seamless for real-time applications. Multicast mobility still waits for a
convincing design. This paper investigates the temporal behaviour of mobile
IPv6 with dedicated focus on topological impacts. Extending the hierarchical
mobile IPv6 approach we suggest protocol improvements for a continuous
handover, which may serve bidirectional multicast communication, as well. Along
this line a multicast mobility concept is introduced as a service for clients
and sources, as they are of dedicated importance in multipoint conferencing
applications. The mechanisms introduced do not rely on assumptions of any
specific multicast routing protocol in use.Comment: 15 pages, 5 figure
A Cross-System Approach for Multimedia Services with IP Multicast in 4G Networks
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
A Distributed Multimedia Communication System and its Applications to E-Learning
In this paper we report on a multimedia communication system including a
VCoIP (Video Conferencing over IP) software with a distributed architecture and
its applications for teaching scenarios. It is a simple, ready-to-use scheme
for distributed presenting, recording and streaming multimedia content. We also
introduce and investigate concepts and experiments to IPv6 user and session
mobility, with the special focus on real-time video group communication.Comment: Including 6 figure
Mobilidade de emissores e receptores em redes com suporte de multicast
Mestrado em Engenharia Electrónica e TelecomunicaçõesEste trabalho de investigação pretende apresentar, desenvolver e avaliar uma
nova solução para a mobilidade de terminais em redes IP com suporte
Multicast. Tendo em conta que são cada vez mais frequentes aplicações
multimédia, tais como, vídeo-conferências, IPTV, entre muitas outras, as quais
requerem uma elevada largura de banda e penalizam a eficácia da rede, é
necessário desenvolver trabalho nesta temática a qual se encontra ainda, nos
nossos dias, pouco aprofundada.
O IP Multicast consiste no envio de apenas um pacote de dados mesmo que
essa informação seja pedida por vários receptores da rede. Para isso, baseiase
no conceito de grupo. Os elementos da rede, que fazem parte da chamada
árvore de distribuição desse grupo multicast, replicam o pacote de forma a
enviar uma cópia do mesmo sempre que o caminho para os receptores
divergir.
Com o advento da tecnologia e tendo em conta as redes de próxima geração,
verifica-se que estas são essencialmente baseadas no conceito de mobilidade.
Por mobilidade entende-se a capacidade de um terminal se conectar a um
outro elemento (Access Router) da rede.
A solução apresentada pretende oferecer de forma eficiente e transparente
suporte ao movimento dos terminais minimizando os tempos de disrupção
associados. Efectuou-se uma análise às soluções existentes e tendo em conta
a convergência das mesmas, para resolver problemas relacionados com
mobilidade de terminais multicast, uma nova solução centrada em Agentbased
é apresentada.
A proposta apresentada foi testada recorrendo ao simulador NS2,
demonstrando a eficiência e escalabilidade desta solução de mobilidade em
redes multicast.
ABSTRACT: This research work aims to produce, develop and evaluate a new solution to
the mobility of terminals in IP Multicast networks. Since, multimedia
applications, such as, video-conferences, IPTV, and many others, are,
nowadays, more common and because these applications require a lot of
bandwidth and reduce the network efficiency, it is necessary to work on this
subject which is not, yet, very developed.
IP Multicast allows sending only one data packet even if such information is
requested by several receivers on the network. For that, it is based on the
concept of group. The elements on the network, which are part of the multicast
delivery tree for that group, replicate the packet, when the path to receivers
differ, in order to send one copy for each one.
With the advent of technology and taking into account next generation
networks, we see that they are essentially based on the concept of mobility.
The concept of mobility means the ability of a terminal to connect to another
element (Access Router) on the network.
The presented solution aims to efficiently and transparently support terminals
movement minimizing the correspondent disruption time. Analyzing current
solutions and taking into account their convergence, in order to solve multicast
terminals mobility issues, a new Agent-based solution is presented.
The proposal was tested using the simulator NS2, demonstrating the efficiency
and scalability of this mobility solution in multicast networks
Optimização de recursos para difusão em redes de próxima geração
Doutoramento em ElectrotecniaEsta tese aborda o problema de optimização de recursos de rede, na entrega de Serviços de Comunicação em Grupo, em Redes de Próxima Geração que suportem tecnologias de difusão. De acordo com esta problemática, são feitas propostas que levam em atenção a evolução espectável das redes 3G em Redes Heterogéneas de Próxima Geração que incluam tecnologias de difusão tais como o DVB. A optimização de recursos em Comunicações em Grupo é apresentada como um desafio vertical que deve cruzar diversas camadas. As optimizações aqui propostas cobrem tanto a interface entre Aplicação e a Plataforma de Serviços para a disponibilização de serviços de comunicação em grupo, como as abstracções e mapeamentos feitos na interface entre a Rede Central e a Rede de Acesso Rádio. As optimizações propostas nesta tese, assumem que o caminho evolutivo na direcção de uma Rede de Próxima Geração é feito através do IP. Em primeiro lugar são endereçadas as optimizações entre a Aplicação e a Plataforma de Serviços que já podem ser integradas nas redes 3G existentes. Estas optimizações podem potenciar o desenvolvimento de novas e inovadoras aplicações, que através do uso de mecanismos de distribuição em difusão podem fazer um uso mais eficiente dos recursos de rede. De seguida são apresentadas optimizações ao nível da interface entre a Rede Central e a Rede de Acesso Rádio que abordam a heterogeneidade das redes futuras assim como a necessidade de suportar tecnologias de difusão. É ainda considerada a possibilidade de aumentar a qualidade de serviço de serviços de difusão através do mapeamento do IP multicast em portadoras unidireccionais. Por forma a validar todas estas optimizações, vários protótipos foram desenvolvidos com base num router avançado para redes de acesso de próxima geração. As funcionalidades e arquitectura de software desse router são também aqui apresentadas.This thesis addresses the problem of optimizing network resource usage, for the delivery of Group Services, in Next Generation Networks featuring broadcast technologies. In this scope, proposals are made according to the expected evolution of 3G networks into Next Generation Heterogeneous Networks that include broadcast technologies such as DVB. Group Communication resource optimization is considered a vertical challenge that must cross several layers. The optimizations here proposed cover both Application to Service Platform interfaces for group communication services, and Core Network to Radio Access Network interface abstractions and mappings. The proposed optimizations are also presented taking into consideration network evolution path towards an All-IP based Next Generation Network. First it is addressed the Application to Service Platform optimization, which can already be deployed over 3G networks. This optimization could potentiate the development of new and innovative applications that through the use of broadcast/multicast service delivery mechanisms could be more efficient network wise. Next proposals are made on the Core Network to Radio Access Network interfaces that address the heterogeneity of future networks and consider the need to support broadcast networks. It is also considered the possibility to increase the Quality of Service of broadcast/multicast services based on the dynamic mapping of IP multicast into unicast radio bearers. In order to validate these optimizations, several prototypes were built based on an advanced access router for next generation networks. Such access router functionalities and software architecture are also presented here
A Common API for Transparent Hybrid Multicast
Group communication services exist in a large variety of flavors and technical
implementations at different protocol layers. Multicast data distribution is
most efficiently performed on the lowest available layer, but a heterogeneous
deployment status of multicast technologies throughout the Internet requires
an adaptive service binding at runtime. Today, it is difficult to write an
application that runs everywhere and at the same time makes use of the most
efficient multicast service available in the network. Facing robustness
requirements, developers are frequently forced to use a stable upper-layer
protocol provided by the application itself. This document describes a common
multicast API that is suitable for transparent communication in underlay and
overlay and that grants access to the different flavors of multicast. It
proposes an abstract naming scheme that uses multicast URIs, and it discusses
mapping mechanisms between different namespaces and distribution technologies.
Additionally, this document describes the application of this API for building
gateways that interconnect current Multicast Domains throughout the Internet.
It reports on an implementation of the programming Interface, including
service middleware. This document is a product of the Scalable Adaptive
Multicast (SAM) Research Group
Monitoring multicast traffic in heterogeneous networks
Estágio realizado no INESC - Porto e orientado pelo Prof. Doutor Ricardo MorlaTese de mestrado integrado. Engenharia Electrotécnica e de Computadores - Major Telecomunicações. Faculdade de Engenharia. Universidade do Porto. 200
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