156 research outputs found
Session Management in Multicast
As a new network technique to efficiently distribute information from a small number of senders to large numbers of receivers, multicast encounters many problems in scalability, membership management, security, etc. These problems hinder the deployment of multicast technology in commercial applications. To overcome these problems, a more general solution for multicast technology is needed. In this paper, after studying current multicast technologies, we summarized the technical requirements for multicast, including data delivery, scalability, security, group management, reliability, and deployment. In order to understand and meet the requirements, we define a life cycle model that most multicast sessions should follow. According to the requirements and the life cycle model, we propose and design a general solution that can control each phase of a session and satisfy most requirements for multicast technology. This general solution has three parts: hierarchical topology auto-configuration algorithm, Session Management Mechanism, and techniques supporting different multicast protocols. To verify the feasibility of our solution and compare its performance with other multicast techniques, we simulate our solution and compare it with PIM-SM and ESM
Prospects for Internet technology
This paper surveys the current developments in Internet technology, with a particular emphasis on performance, and the growing need for various guarantees of quality of service. It discusses hardware technologies for increased bandwidth, mechanisms for requesting and providing specific qualities of service, and various scaling issues. Fi-nally it discusses mechanisms needed for (but not the economics of) the Internet in the mass market. To this end, we survey changes in the areas of addressing, and flow management. 1
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IP Mobile Multicast over Next Generation Satellite Networks. Design and Evaluation of a Seamless Mobility Framework for IP Multicast Communications over a Multi-beam Geostationary Satellite Network
The inherent broadcast nature of satellites, their global coverage and direct
access to a large number of subscribers give satellites unrivalled advantages in
supporting IP multicast applications. A new generation of satellite systems that
support regenerative on-board processors and multiple spot beam technology
have opened new possibilities of implementing IP multicast communication over
satellites. These new features enable satellites to make efficient use of their
allocated bandwidth resources and provide cost effective network services but
equally, create new challenges for mobile satellite terminals. IP mobility support
in general and IP mobile multicast support in particular on mobile satellite
terminals like the ones mounted on continental flights, maritime vessels, etc.,
still remain big challenges that have received very little attention from the
research community.
Up till now, there are no proposed mechanisms to support IP multicast for
mobile receivers/sources in multi-beam satellite networks in open literature.
This study explores the suitability of IP multicast mobility support schemes
defined for terrestrial networks in a satellite environment and proposes novel
schemes based on the concepts of Home and Remote subscription-based approaches, multiple interface and PMIPv6 protocol. Detailed analysis and
comparison of results obtained from the proposed schemes, Mobile IP (MIP)
Home and Remote subscription-based approaches (for terrestrial networks)
when implemented on a reference multi-beam satellite network are presented.
From these results, the proposed schemes outperform the MIP Home and
Remote subscription-based approaches in terms of gateway handover latency,
number of multicast packets lost and signalling cost over the satellite air
interface
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 new framework for minimising handover in multicast mobility
Nowadays, mobile devices support a variety of multimedia applications such as live video, radio or online gaming. People spend their time on mobile devices for entertainment more and more via the internet. Due to the requirements of multimedia applications over wireless communication those applications require a huge bandwidth on the network to support them, which creates problems for the network provider. However, one pattern that is appropriate for the efficient delivery of multimedia messages is multicast delivery.Multicast services do, however, introduce challenges within the network when the recipients of the service are moving. Powerful multicast routing protocols are designed for static client IP addresses. Hence, when the mobile node changes the location, it introduces the problem of access network handover. Therefore, this is the aim of the research where a new framework will be developed for multicast mobility within WiFi network to reduce and provide smooth mobility when handover occurs. This research is focused on techniques to reduce handover latency, minimize packet loss and provide connection when a user moves between network zones.To achieve these aims, this designed framework lets mobile nodes send the message to register to foreign agents in advance for addressing IP address of the new zone and to establish the multicast tree earlier. Moreover, there are processes that keep the connection of the path alive.The framework is being simulated on OPNET Modeler for evaluating the performance in terms of handover latency time, the number of packet loss and so on. There are many scenarios that have been tested. According to the results, it shows that the new framework has reduced handover latency time around 60% on average and minimized packet delay approximately 0.7 - 150 ms on mobile node depending on network topology. This framework can provide IP address reconfiguration, binding update, joining multicast group and distribution path of multicast tree in advance. However, there are some overheads and cost that this framework has to pay for such as IP address database, increasing broadcast within networks and keeping connection path alive
Multicast for ubiquitos streaming of multimedia content to mobile terminals : Network architecture and protocols
The Universal Mobile Telecommunication Services (UMTS) network was envisioned to carry a wide range of new services; however, the first UMTS release was not designed to efficiently support multimedia content. In this thesis we analyse several mechanisms, and suggest architectural changes to improve UMTS’s capacity for a subset of the multimedia services; high-bandwidth group services. In our initial work we have suggested how IP multicast protocols can be used in the UMTS network to reduce the required network capacity for group services. This proposal was one of many suggestions for the evolving Multimedia Broadcast/Multicast Service (MBMS) architecture for UMTS. The next technique we have suggested and analysed is a new wireless channel type named the "sticky-channel"; this channel is intended for sparsely populated multicast groups. The sticky-channel is able to stick to mobile multicast members in the boarder area of neighbouring radio cells, thus some base stations does not need to broadcast the multicast data. Consequently, the total number of broadcast channels needed to cover a given area is reduced. There is a marginal reduction of required resources with this technique. In the main part of our work we have studied heterogeneous multihop wireless access for multicast traffic in the UMTS network. In a heterogeneous wireless access network, the wireless resources needed to distribute high-bandwidth group services, can be shared among cooperating network technologies. Mobile terminals with a UMTS interface and an IEEE 802.11 interface are readily available, consequently a heterogeneous network with UMTS and 802.11 links will be easy to deploy. We have described a heterogeneous architecture based on those wireless technologies. In this architecture, the range of a UMTS radio channel is reduced, and local IEEE 802.11-based Mobile Ad Hoc Networks (MANETs) forward the data to users located outside the coverage of the reduced UMTS channel. The wireless resources required to transmit a data packet are proportional to (at least) the square of the distance the packet must travel, thus a reduction in the channel range releases a significant amount of UMTS radio resources. Detailed simulation results showed acceptable service quality when the UMTS broadcast channel range is more than halved. Finally we have studied whether Forward Error Correction (FEC) at the packet-level on multicast flows could improve the performance of the heterogeneous wireless access network. There is a marginal improvement. Most of the protection brought by the FEC code has been used to repair the increased packet-loss introduced by the FEC overhead
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