Multimedia Communication in Wide-Area Networks

9508274托斯利广域网络对多媒体应用提出了与通信相关的新挑战，因为丢包、更长的延迟和更大的用户数量成为重要因素。虽然新兴的ATM网络为支持这种多媒体应用提供了通信服务，但今天的互联环境和传统使得两个终端主机之间的端到端ATM连接在可预见的未来是不可能的。该项目的研究在开发支持实时多媒体应用所需的网络基础设施方面迈出了及时而重要的一步。该建议包括一系列理论和实验研究，旨在设计和评估可扩展服务，以支持广域网或网际网络中的实时多媒体应用。具体地说，研究人员将：1)开发和评估面向接收者的方法，以提供可扩展的可靠组播服务。基本问题是了解如何在发送方和接收方之间分配协议功能，如何使用多播来提供可靠的多播，以及如何在差错恢复协议中使用特定于应用的语义信息；以及2)开发和评估终端主机机制，例如播放调整算法和专用差错恢复协议，以提高由几个不同的实时应用获得的服务质量。研究人员将利用有关组件应用程序的应用程序特定信息-在这种情况下，它们的不同时间限制。*达琳·费舍尔项目经理网络和通信研究项目4201威尔逊大道。弗吉尼亚州阿灵顿22230(703)306-306-06211175室(传真)

9508274 Towsley Wide-area networks pose new communication-related challenges for multimedia applications as packet loss, longer delays, and larger user populations become important factors. While emerging ATM networks provide communication services for supporting such multimedia applications today's internetworked environment and legacy make end-to-end ATM connectivity between two end hosts unlikely in the foreseeable future. Research in this project represents a timely and important step in developing the network infrastructure needed to support real-time multimedia applications. This proposal includes a mix of theoretical and experimental research aimed at the design and evaluation of scalable services for supporting real-time multimedia applications in a wide-area network or internetwork. Specifically, the researchers will: 1) develop and evaluate receiver-oriented approaches for providing scalable reliable multicast services. The fundamental concerns are to understand how to allocate protocol functionality among the sender and receivers, how to use multicast to provide reliable multicast, and how to use application-specific semantic information in error recovery protocols; and 2) develop and evaluate end host mechanisms, such as playout adjustment algorithms and special-purpose error-recovery protocols, for enhancing the quality of service attained by several different real-time applications. The researchers will exploit application-specific information about the component applications - in this case their different timing constraints. *** ******* Darleen Fisher Program Manager Networking and Communications Research Program 4201 Wilson Blvd. Room 1175 Arlington Va 22230 (703) 306-1949 (703) 306-0621 (FAX)