A Scaleable Multicast Protocol to Enable Future-Generation Large Scale Multimedia Applications

可扩展的组播协议，支持下一代大规模多媒体应用

• 批准号: 0088026
• 负责人: Kien Hua
• 金额: $ 30万
• 依托单位: The University of Central Florida Board of Trustees
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-15 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0088026&HistoricalAwards=false
• 关键词: Scaleable; Multicast; Protocol; Enable; Future

A picture is worth a thousand words, and the addition of sound and motion can breathe life into a picture.As a result, the use of video in all kinds of multimedia applications has become an important developmentin the 1990s. In particular, Video on demand (VOD) is a core technology for many important applicationssuch as digital libraries, distance learning, electronic commerce, entertainment, public informationsystems, etc.The simplest video delivery technique employs a dedicated stream for each service request. Obviously,this scheme is too expensive and has been shown to have little scalability. To vastly reduce this cost, onecan leverage multicast technology to allow multiple clients to share a video stream. Unfortunately, today'smulticast technology was developed in the 80's, and was not optimized for such applications. Missing amulticast could mean a long wait until the next multicast. This limitation has recently led to a large bodyof research looking for remedies at the application level.Application-level solutions, however, cannot address all the drawbacks, particularly traffic congestioncaused by too many multicasts. In fact, this proposal is motivated by application-level work done bythe investigator in his last NSF project (from 1998 to 2000). The achievements of that project, thoughsignificant, were constrained by the limitation of standard multicast. Minimizing the multicast frequencyis crucial for any multicast-based applications, particularly those running on a public network such as theInternet. Attaining this goal requires a fundamental change in the multicast concept. The investigatorproposes enabling the multicast tree to deliver the entire video to all the receivers who may subscribe tothe multicast at different times. This new capability would significantly reduce the number of multicastsnecessary, and therefore lower the network resource requirements. At first sight, this seems like a missionimpossible. But on the contrary, this can be achieved by allowing the routers on the multicast tree tointercept and cache a video stream passing through. The data can be relayed to subsequent subscribers tofurther extend the multicast tree. In this project, the investigator proposes to develop a suite of techniquesto make such an environment practical for future-generation large-scale multimedia applications.To assess the potential of the proposed idea, the investigator has designed an initial version of hisCaching Multicast Protocol (CMP). The preliminary study indicates that this approach has the potentialto revolutionize the way in which multimedia information is disseminated. This scheme is much morescalable and less expensive than application-level solutions. The new communication paradigm, however,demands new research at the network level. In this project, the investigator proposes to study issues suchas cache organization, cache replacement policies, multicast routing algorithms, congestion control, clientand server protocols, etc. In addition, he will implement a prototype, consisting of CMP-capable routers,CMP-compliant servers (sources) and CMP-compliant clients (destinations) to examine the practicality ofthe proposed techniques.The significance of this project is in advancing multicast technology to enable large-scale deploymentof multimedia applications. Although many great advances have been made in the field of informationtechnology, none have had as great and direct an impact on the daily lives of ordinary citizens as multime-diainformation systems. As such, the benefits of this research will reach many people in society. In termsof education, this project will help to support three doctoral students. The investigator has a good recordof using NSF projects to train students for teaching careers. After these students graduate, they can helpto spread the CMP expertise developed from this project to their new institutions. Other graduate studentstaking our advanced databases course can also benefit from this work by experimenting with various newmulticast applications on the CMP testbed. To reach out to members of communities, materials resultingfrom this research will be disseminated on the investigator's research group website.

一张图片胜过千言万语，声音和运动的加入可以为图片注入生命。因此，视频在各种多媒体应用中的使用已成为20世纪90年代的一项重要发展。尤其是视频点播(Video On Demand，VOD)是数字图书馆、远程教育、电子商务、娱乐、公共信息系统等许多重要应用的核心技术，最简单的视频交付技术为每个服务请求提供专用的流。显然，这个方案太昂贵了，而且被证明几乎没有可伸缩性。为了大大降低这一成本，可以利用多播技术来允许多个客户端共享一个视频流。不幸的是，今天的组播技术是在80年代的S发展起来的，并没有针对这样的应用进行优化。丢失多播可能意味着要等待很长时间才能进行下一次多播。然而，应用程序级的解决方案不能解决所有的缺点，特别是由太多的多播引起的流量拥堵。事实上，这项建议的动机是调查员在他的上一个NSF项目(从1998年到2000年)中所做的应用程序级别的工作。该项目的成就虽然意义重大，但受到标准多播的限制。最大限度地减少组播频率对于任何基于组播的应用来说都是至关重要的，尤其是那些运行在公共网络上的应用，例如互联网。要实现这一目标，需要从根本上改变组播概念。研究人员建议使多播树能够将整个视频传递给可能在不同时间订阅多播的所有接收者。这一新功能将显著减少所需的组播数量，从而降低网络资源需求。乍一看，这似乎是一项不可能完成的任务。但相反，这可以通过允许多播树上的路由器拦截和缓存通过的视频流来实现。数据可以被转发到后续订户以进一步扩展多播树。在这个项目中，研究人员建议开发一套技术来使这种环境适用于下一代大规模多媒体应用。为了评估所提出的想法的潜力，研究人员设计了一个初始版本的HisCachingMulticast协议(CMP)。初步研究表明，这种方法有可能彻底改变多媒体信息的传播方式。与应用程序级解决方案相比，该方案具有更强的可伸缩性，并且成本更低。然而，新的传播范式需要在网络层面进行新的研究。在这个项目中，研究人员提出了研究缓存组织、缓存替换策略、多播路由算法、拥塞控制、客户端和服务器协议等问题。此外，他还将实现一个原型，由支持MP的路由器、兼容CMP的服务器(源)和兼容CMP的客户端(目的地)组成，以检验所提出的技术的实用性。本项目的意义在于推动组播技术的发展，使多媒体应用能够大规模部署。虽然在信息技术领域取得了许多重大进展，但对普通公民日常生活的影响没有一个像多时间信息系统那样巨大和直接。因此，这项研究的好处将惠及社会上的许多人。在教育方面，该项目将帮助支持三名博士生。这位调查员在使用NSF项目培训学生从事教学工作方面有很好的记录。在这些学生毕业后，他们可以帮助将从这个项目中发展出来的《议定书》专业知识传播到他们的新机构。其他正在学习我们的高级数据库课程的研究生也可以从这项工作中受益，他们可以在CMP试验台上试验各种新的多播应用程序。为了接触社区成员，这项研究产生的材料将在调查员研究小组的网站上传播。