multimedia conferencing systems axe usually large, complex software systems. We describe a local control architecture and communication protocols that allow to tie together media agents, controllers and auxiliary appl...
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Distributed systems that span large geographic distances or manage large numbers of objects are already common place. In such systems, programming applications with even modest reliability requirements to run correctl...
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Distributed systems that span large geographic distances or manage large numbers of objects are already common place. In such systems, programming applications with even modest reliability requirements to run correctly and efficiently is a difficult task due to asynchrony and the possibility of complex failure scenarios. We describe the architecture of the RELACS communication subsystem that constitutes the microkernel of a layered approach to reliable computing in large-scale distributed systems. RELACS is designed to be highly portable and implements a very small number of abstractions and primitives that should be sufficient for building a variety of interesting higher-level paradigms.< >
With the increasing availability of workstations and networking facilities, desktop conferencing systems have attracted a considerable amount of attention. In our design of Nebula, an experimental conferencing system,...
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With the increasing availability of workstations and networking facilities, desktop conferencing systems have attracted a considerable amount of attention. In our design of Nebula, an experimental conferencing system, one of the design objectives is to use a distributed approach to provide reliable service while maintaining overall system simplicity. Another objective is to model the operation of the conferencing system on actual teleconferencing systems and to provide flexibility to the user in controlling the conference. Finally, the system is to have a well defined programming interface to allow user applications to developed easily. This paper provides a detailed overview of Nebula, with special emphasis on the conferencing capabilities. System requirements and various design issues will be discussed in the next section. The system architecture, in particular the major building blocks, will be discussed next. Finally the applications built on top of the conferencing system is described.
It is generally accepted that most of the currently existing transport protocols such as TCP/UDP and OSI Transport protocols are not suitable for multimediaconferenceapplications, in which different media services r...
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ISBN:
(纸本)0780318250
It is generally accepted that most of the currently existing transport protocols such as TCP/UDP and OSI Transport protocols are not suitable for multimediaconferenceapplications, in which different media services require different service requirements. However, the wide use of these protocols make them attractive to people who are interested in finding the performance of these protocols and quickly bring multimedia to the desktop. In this paper we present the design, realization and analysis of a multimediaconference system on FDDI using TCP/ip protocols. End-to-end delays and jitters are measured to compare the performances of two architectures: one architecture is based on TCP in which all applications services, interactive video, interactive voice and data, are multiplexed at the application level and transmitted through TCP;the other architecture has interactive video and voice transmitted through UDP and data transmitted through TCP. We also present a new way to measure the delay which avoids the frequency synchronization problem. Important aspects of the experience gained from building the software for the multimediaconference are also presented, especially with respect to parallelism within different parts of the software.
The proceedings contain 24 papers. The special focus in this conference is on multimedia Transport and Teleservices. The topics include: A mail-based teleservice architecture for archiving and retrieving dynamically c...
ISBN:
(纸本)9783540587590
The proceedings contain 24 papers. The special focus in this conference is on multimedia Transport and Teleservices. The topics include: A mail-based teleservice architecture for archiving and retrieving dynamically composable multimedia documents;the global store server - a multimedia teleservice component;from broadband network services to a distributed multimedia support-environment;managing shared ephemeral teleconferencing state;computational components for synchronous cooperation on multimedia information;a binding architecture for multimedia networks;implementation of a end-to-end quality of service management scheme;a formal description technique supporting expression of quality of service and media synchronization;on the synchronization mechanisms for multimedia integrated services networks;efficient support for multiparty communication;QoS negotiation for multicast communications;support for high-performance multipoint multimedia services;providing support for data transfer in a new networking environment;congestion avoidance for video over ip networks;congestion control in multimedia communication with heterogenous networks and receivers;resource requirements for VBR mpeg traffic in interactive applications;transmission of MPEG2 applications over ATM networks;a platform for multimedia telecooperation bridging endsystem heterogeneity;a scheme for multimedia and hypermedia synchronization;integration of existing applications into a conference system and the CIO multimedia communication platform.
The architecture and implementation of a small distributed conferencing system and shared multimedia application is described. The conferencing system, which is based on OSI upper layer services and TCP/ip as the tran...
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The architecture and implementation of a small distributed conferencing system and shared multimedia application is described. The conferencing system, which is based on OSI upper layer services and TCP/ip as the transport/network layer, is used to study various aspects of service distribution through process placement strategies in a networked environment. The system also serves as a testbed for the implementation of additional application services, in order to study the suitability of upper layer OSI protocols for interactive multimediaapplications. We describe the design and implementation of one such distributed multimedia application, namely a shared office whiteboard under X-Windows.
It is generally accepted that most of the currently existing transport protocols such as TCP/UDP and OSI transport protocols are not suitable for multimediaconferenceapplications, in which different media services r...
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It is generally accepted that most of the currently existing transport protocols such as TCP/UDP and OSI transport protocols are not suitable for multimediaconferenceapplications, in which different media services require different service requirements. However, the wide use of these protocols make them attractive to people who are interested in finding the performance of these protocols and quickly bring multimedia to the desktop. The authors present the design, realization and analysis of a multimediaconference system on FDDI using TCP/ip protocols. End-to-end delays and jitters are measured to compare the performances of two architectures: one architecture is based on TCP in which all applications services, interactive video, interactive voice and data, are multiplexed at the application level and transmitted through TCP; the other architecture has interactive video and voice transmitted through UDP and data transmitted through TCP. The authors also present a new way to measure the delay which avoids the frequency synchronization problem. Important aspects of the experience gained from building the software for the multimediaconference are also presented, especially with respect to parallelism within different parts of the software.< >
The authors examine the use of a new architecture for the design of system software. The architecture allows the construction of flexible system software components, and the resulting realizations can be tailored to t...
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The authors examine the use of a new architecture for the design of system software. The architecture allows the construction of flexible system software components, and the resulting realizations can be tailored to the needs of various applications. The focus is on the application of that architecture to distributed shared memory (DSM). The system software architecture, called pi , defines elements of system software as generalized objects. These x objects have two interfaces: one for usage and one for additional control. pi enables system software components to evolve as computer hardware evolves and it addresses the demands emerging classes of applications like object-oriented databases and multimedia. The pi architecture and its use in a DSM subsystem for clustered workstations are discussed.< >
Starting with the imminent roll-out of the ipmultimediasubsystem (IMS) and fourth-Generation networking technology, Next Generation Networks (NGN) are gradually becoming reality, with charging and Quality-of-Service...
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ISBN:
(数字)9783642017964
ISBN:
(纸本)9783642017957
Starting with the imminent roll-out of the ipmultimediasubsystem (IMS) and fourth-Generation networking technology, Next Generation Networks (NGN) are gradually becoming reality, with charging and Quality-of-Service (QoS) issues as two of the key drivers for the evolution toward the convergent all-ip network of the future. Therefore, the 6th international Workshop on Internet Charging and QoS Technology (ICQT 2009) was devoted to discussing the most recent approaches, models, and mechanisms in this highly interesting and important research area. The present volume of the Lecture Notes in Computer Science series includes those papers presented at ICQT 2009—collocated this year with the IFip Networking 2009 conference—taking place on May 15, 2009, in Aachen, Germany and hosted by the Rheinisch-Westfälische Technische Hochschule (RWTH Aachen). For the commercial success of future QoS-enabled communication services, the emergence of viable business models, pricing schemes, and charging and accounting mechanisms is of paramount importance. Problems in this domain can only be addressed through a broad interdisciplinary approach linking together a variety of technical and economic perspectives, which are constantly driving a plethora of relevant research t- ics for application developers, business architects, network providers, service providers, and customers. Within the current trend toward a convergent NGN architecture, compe- tion modeling, pricing mechanisms, and the economics of inter-domain traffic are of specific importance and urgency. Thus, they determined—in the form of three technical sessions—the core of the ICQT 2009 program.
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