A reliable multicast webcast protocol for multimedia collaboration and caching
A reliable multicast webcast protocol for multimedia collaboration and caching
复制标题
用于多媒体协作和缓存的可靠多播网络广播协议
DOI：
10.1145/354384.354399
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
Jay Lepreau
中科院分区：
文献类型：
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作者：
L. Wright;S. McCanne;Jay Lepreau
旨在促进远距离协作的大规模、多点、多媒体会议应用程序越来越受欢迎。这些协作环境通常由实时音频、视频和共享绘图应用程序组成，有助于使协作者的地理位置变得无关紧要。为了补充这些现有的协作应用程序，具有通过万维网（WWW）同步分发文档的能力将是有用的。网络中同步信息传播的一种模式是网络广播，其中数据同时分发到多个目的地。然而，当应用于网络广播时，WWW的传统单播客户端/服务器通信模型受到影响;需要许多客户端使用客户端/服务器模型同时从源服务器获取数据的解决方案可能会导致服务器和链路过载。已经提出了一些网播解决办法。许多具有有限的可扩展性，因为它们是基于单播，而其他使用多播更可扩展的数据传输，但需要服务器修改或具有严格的架构。我们相信，成功的网络广播解决方案将提供可扩展的，可靠的交付，但仍然与现有的Web基础设施兼容。在本文中，我们描述了一个网络直播的设计，利用应用程序级框架（ALF）的设计方法，提高了以前的设计。我们建立在可扩展的可靠多播（SRM）框架，这是基于ALF，创建一个自定义协议，以满足网络广播的可扩展性需求。我们采用的协议在一个架构，包括两个可重用的组件：一个webcache组件和浏览器控制组件。我们已经实现了我们的设计使用MASH多媒体应用程序工具包和SRM协议模块称为libsrm。我们提出了一个简单的性能评估的结果，并报告使用MASH和libsrm的经验教训。
Large-scale, multi-point, multimedia conferencing applications designed to facilitate long-distance collaboration are enjoying growing popularity. Usually composed of real-time audio, video and shared-drawing applications, these collaborative environments help render the geographical location of collaborators irrelevant. To complement these existing collaborative applications, it would be useful to have the ability to distribute documents synchronously over the World Wide Web (WWW). One model for synchronized information dissemination within the Web is webcasting in which data are simultaneously distributed to multiple destinations. The WWW's traditional unicast client/server communication model suffers, however, when applied to webcasting; solutions which require many clients to simultaneously fetch data from the origin server using the client/server model will likely cause server and link overload. A number of webcasting solutions have been proposed. Many have limited scalability because they are based on unicast while others use multicast for more scalable data delivery but require server modification or have rigid architectures. We believe that successful webcasting solutions will provide scalable, reliable delivery yet still be compatible with the existing Web infrastructure. In this paper we describe a webcast design that improves upon previous designs by leveraging application level framing (ALF) design methodology. We build upon the Scalable Reliable Multicast (SRM) framework, which is based upon ALF, to create a custom protocol to meet webcast's scalability needs. We employ the protocol in an architecture consisting of two reusable components: a webcache component and a browser control component. We have implemented our design using the MASH multimedia application toolkit and a SRM protocol module called libsrm. We present the results of a simple performance evaluation and report on lessons learned while using MASH and libsrm.