CAREER: From Protocol Support to Applications: Elevating Multicast to a Ubiquitous Internet Service

职业：从协议支持到应用程序：将组播提升为无处不在的互联网服务

• 批准号: 9982769
• 负责人: Kevin Almeroth
• 金额: $ 20万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9982769&HistoricalAwards=false
• 关键词: CAREER; Protocol; Support; Applications; Elevating

The investigation of multicast communication as a service in the Internet has been an issue for nearly a decade. And in that time, much progress has been made. From its early inception as a means of streaming audio and video to researchers around the world, the Multicast Backbone (MBone) has grown into an infrastructure supporting commercial applications. But, even though great strides have been made, there are still numerous, serious technical problems to be solved. The rapid growth in multicast users, and the rapid growth in the interest in multicast means not only more and more multicast-capable sites are being added but more demands are being made for a richer set of multicast-base services. As multicast grows in use, the need to make good on the promises of scalability becomes even more important. Furthermore, the complexities of multicast protocols are significantly greater than for unicast protocols. Multicast protocols must communicate state information to manage the dynamic growth of multicast trees and ensure traffic flows only on necessary links; they must implement congestion control among many receivers instead of just one; and they must support management fuctions in an environment with more complexity than traditional management protocols were designed to handle. If multicast implementors have learned anything, it is that fuctions that are easy for unicast protocols are not so easy for multicast. Once one problem is solved, there is another set of problems to be identified and then solved. But even with all the hurdles to overcome the potential utility of a ubiquitous multicast service is immense. Once the protocol issues are more fully solved, the potential for new multicast-based applications and services will carry the Internet to a new level of utility. While multicast is quickly evolving and industry is beginning to take notice, there are still problems to be solved by the academic community. In the last several years, multicast has developed into more than just a research initiative. Multicast is now of interest to many companies. These companies see the value in multicast and also see the value in having multicast as a premiere Internet service. However, just because multicast is being touted as a service ready to roll-out, does not mean all of the technical problems have been solved. More importantly, it would be dangerous for the academic community to believe industry will assume full responsibility for solving the most important problems. The role of academia, and the goal of the research plan described in this proposal, is to support the investigation of problems limiting the effectiveness of the Internet-wide deployment of multicast. Furthermore, results of this research will hopefully be applied in next-generation high speed regional (Ca1REN-2) and national (vBNS and Internet2) networks. The basic goal of the research outlined in this proposal is to continue evolving multicast into an Internet service. A number of multicast research topics and deployment issues are targeted. Because multicast communication is both the subject of ongoing academic research and deployment issues, this CAREER proposal is an investigation of issues along two axes: (1) networking issues ranging from the data link layer up to the application layer, and (2) the type of research ranging from basic research to applied research. Significant thought has been given to organizing this CAREER proposal in a manner that reflects the changing philosophy of academia. The first axis is developed based on the philosophy that applications drive the need to develop new Internet services. In the network, Internet service enable new paradigms and applications to be developed. The second axis is developed based on the philosophy that a new era has begun in which successful faculty must be capable of addressing both fundamental research issues and applied research issues across a range of areas. The proposed education plan relates very closely to the proposed research plan. The educational mission is to teach undergraduates and graduates the fundamental aspects of networking and then to relate them to how things work in the Internet. The key strength of the educational mission is its close ties to the research plan. In particular, the digital classroom is the enabling concept which bring education and research together. The digital classroom is an ideal application. It embodies much of my research philosophy and is an excellent bridge for students. They can see the need for distance learning at the macro-level and can use that knowledge to put into context the micro-level projects. The best way to evaluate a digital classroom is to use it, and the best way to build a digital classroom is to have students (not as chep labor but as eventual "useer") build it. The classroom provides a traditional environment for students to learn theoretical topics, the classroom can also be a place where traditional topics using non-traditional methods, and the classroom is an ideal place to motivate students to think beyond textbooks and closed-end problems. While distance learning is the subject of much research, academic faculty are in the unique position of using, evaluation, proposing, and developing the techniques and tools that will someday define and enable distance learning.

将多播通信作为一种服务在互联网上进行研究已经有近十年的历史了。在这段时间里，取得了很大的进展。从最初作为向世界各地的研究人员传输音频和视频的一种手段开始，多播骨干网（MBone）已经发展成为支持商业应用的基础设施。但是，尽管已经取得了很大的进步，仍然有许多严重的技术问题需要解决。组播用户的快速增长和对组播兴趣的快速增长不仅意味着越来越多的支持组播的站点被添加，而且对更丰富的组播基础服务提出了更多的要求。随着多播应用的增长，实现可伸缩性的承诺变得更加重要。此外，组播协议的复杂性明显大于单播协议。组播协议必须通信状态信息来管理组播树的动态增长，并确保流量只在必要的链路上流动；它们必须在许多接收器之间实现拥塞控制，而不是只有一个接收器；而且，它们必须在比传统管理协议所设计的要复杂得多的环境中支持管理功能。如果组播实现者学到了什么，那就是对于单播协议来说容易的功能对于组播来说就不那么容易了。一旦一个问题解决了，就会有另一组问题需要识别和解决。但是，即使克服了所有的障碍，无处不在的多播服务的潜在效用也是巨大的。一旦协议问题得到更充分的解决，新的基于多播的应用程序和服务的潜力将把互联网带到一个新的实用水平。虽然多播正在迅速发展，工业界也开始注意到它，但学术界仍有一些问题需要解决。在过去的几年里，多播已经不仅仅是一个研究项目。多播现在引起了许多公司的兴趣。这些公司看到了多播的价值，也看到了将多播作为首要互联网服务的价值。然而，仅仅因为多播被吹捧为一种准备推出的服务，并不意味着所有的技术问题都得到了解决。更重要的是，如果学术界认为工业界将承担解决最重要问题的全部责任，那将是危险的。学术界的角色，以及本提案中描述的研究计划的目标，是支持对限制互联网范围内多播部署有效性的问题的调查。此外，本研究成果有望应用于下一代高速区域（Ca1REN-2）和国家（vBNS和Internet2）网络。本提案中概述的研究的基本目标是继续将多播发展成为一种互联网服务。一些组播研究课题和部署问题是有针对性的。由于多播通信既是正在进行的学术研究和部署问题的主题，因此本CAREER提案是沿着两个轴对问题进行调查：(1)从数据链路层到应用层的网络问题，以及(2)从基础研究到应用研究的研究类型。以一种反映学术界不断变化的哲学的方式组织这一职业建议已经得到了重要的思考。第一个轴是基于应用程序驱动开发新Internet服务的需求这一理念开发的。在网络中，Internet服务使新的范例和应用得以发展。第二个轴心是基于这样一种理念发展起来的：一个新时代已经开始，在这个时代，成功的教师必须能够解决一系列领域的基础研究问题和应用研究问题。拟议的教育计划与拟议的研究计划密切相关。教育任务是教授本科生和毕业生网络的基本方面，然后将他们与互联网上的事物如何工作联系起来。教育使命的关键优势在于它与研究计划的紧密联系。特别是，数字教室是将教育和研究结合在一起的使能概念。数字教室是一个理想的应用。它体现了我的许多研究理念，是学生的一个很好的桥梁。他们可以在宏观层面上看到远程学习的需求，并可以利用这些知识将微观层面的项目纳入背景。评估一个数字教室的最好方法是使用它，而建造一个数字教室的最好方法是让学生（不是廉价劳动力，而是最终的“用户”）建造它。课堂为学生学习理论课题提供了一个传统的环境，课堂也可以成为传统课题运用非传统方法的场所，课堂是激发学生超越教科书和封闭式问题思考的理想场所。虽然远程学习是许多研究的主题，但学术教师在使用、评估、提出和开发技术和工具方面处于独特的地位，这些技术和工具有朝一日将定义和实现远程学习。