CAREER: Flexible Strategies for Internet Content Distribution

职业：互联网内容分发的灵活策略

• 批准号: 0093296
• 负责人: John Byers
• 金额: --
• 依托单位: Trustees of Boston University
• 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: 2001-06-01 至 2007-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0093296&HistoricalAwards=false
• 关键词: CAREER; Flexible; Strategies; Internet; Content

The emergence of new technologies for content distribution including content delivery networks (CDNs, end system multicast, distributed content exchange and application-level anycast are fundamentally changing the relationships between consumers and producers of digital content. Whereas traditional approaches to content delivery are predicated on point-to-point connections from a client to a single origin server, these new mechanisms for content distribution fundamentally undermine the assumptions inherent in that model. For example, CDNs redirect clients to a number of equivalent replica servers, while end system multicast goes further and blurs the distinction between client and server by requiring that every participant who wishes to access content serve content as well. To illustrate this point, consider the access graph plotting the flow of TCP connections serving a popular document through the network at an instant in time. Until very recently, this graph could easily be characterized as forming a hub-and-spoke topology with the hub at the origin server; now its complex structure is little known except perhaps to network engineers within the CDNs themselves. Broadly, the researcher's interests lie in characterizing the impact that new and increasingly distributed content delivery mechanisms will have on network traffic, resource management and the design of network protocols. In the research component of the researcher's career development program, he focuses on strategies for addressing the challenges and opportunities that distributed content delivery mechanisms will place on reliable transport protocols. In particular, the complex one-to-many and many-to-many relationships between consumers and producers of digital content will place strain on transport protocols such as TCP, as those protocols are not designed to accomodate the fluid interactions which will take place when users have a multiplicity of service options. The researcher argues for lightweight reliable transport services designed for maximum flexibility which can accomodate connection preemption, connection suspension, connection migration and connection aggregation. While these considerations are fundamental , they have not been carefully studied in the context of TCP because of daunting technical hurdles, complexity, and absence of a driving need. The researcher brings new techniques to bear on the problem, as the proposed work leverages his experience with fast forward error correcting coding techniques which he has applied in the domain of reliable multicast [11] and downloading digital content from multiple mirror sites in parallel [10]. In some of the settings considered, such as dynamic server selection and redirection, the flexibility which the proposed techniques afford can be considered to be a performance optimization, but in other settings, such as providing reliability for end system multicast, the researcher argues that the flexible services proposed are essential to delivering high performance. The proposed educational aspect of the researcher's career development program focuses on enhancing the undergraduate and graduate student experience in his department and building a stronger basis for industrial and inter-institutional networking research collaborations in the Boston area. Proposed activities center around ongoing projects to promote undergraduate involvement in networking research; to enhance the department's networking curriculum; and to encourage students to participate in the computer science community outside of the university, whether by volunteering at a community outreach program or by becoming involved in local organizations of computer scientists. An exciting initiative which the researcher is e actively involved in and which will help achieve these goals is the institution of a center for networking research at Boston University.

内容分发新技术的出现，包括内容分发网络（CDN）、终端系统组播、分布式内容交换和应用级选播，正在从根本上改变数字内容消费者和生产者之间的关系。 虽然传统的内容交付方法是基于从客户端到单个源服务器的点对点连接，但这些新的内容分发机制从根本上破坏了该模型中固有的假设。 例如，CDN将客户端重定向到多个等效的复制服务器，而端系统组播则更进一步，通过要求希望访问内容的每个参与者也提供内容来模糊客户端和服务器之间的区别。 为了说明这一点，考虑访问图，该图绘制了在某个时刻通过网络为一个流行文档提供服务的TCP连接流。 直到最近，这个图可以很容易地被描述为形成一个中心辐射拓扑，其中集线器位于源服务器;现在，除了CDN本身的网络工程师之外，它的复杂结构几乎一无所知。 从广义上讲，研究人员的兴趣在于表征新的和越来越分布式的内容交付机制将对网络流量，资源管理和网络协议的设计产生的影响。 在研究人员的职业发展计划的研究部分，他专注于解决分布式内容交付机制将对可靠的传输协议带来的挑战和机遇的策略。 特别地，数字内容的消费者和生产者之间的复杂的一对多和多对多关系将对诸如TCP的传输协议施加压力，因为这些协议不是被设计成适应当用户具有多种服务选项时将发生的流体交互。 研究人员认为，轻量级的可靠的传输服务设计的最大灵活性，可以容纳连接抢占，连接暂停，连接迁移和连接聚合。 虽然这些考虑是基本的，但由于令人生畏的技术障碍、复杂性和缺乏驱动需求，它们尚未在TCP的上下文中进行仔细研究。 研究人员带来了新的技术来解决这个问题，因为所提出的工作利用了他在可靠多播[11]和并行从多个镜像站点下载数字内容[10]领域中应用的快速前向纠错编码技术的经验。 在一些考虑的设置，如动态服务器选择和重定向，所提出的技术提供的灵活性可以被认为是一个性能优化，但在其他设置，如提供可靠性的终端系统组播，研究人员认为，灵活的服务，提出了提供高性能是必不可少的。 研究人员职业发展计划的拟议教育方面侧重于提高他所在部门的本科生和研究生的经验，并为波士顿地区的工业和机构间网络研究合作奠定更坚实的基础。 拟议的活动围绕正在进行的项目，以促进本科生参与网络研究;加强部门的网络课程;并鼓励学生参与大学以外的计算机科学社区，无论是通过在社区外展计划志愿服务还是通过参与当地计算机科学家组织。 一个令人兴奋的倡议，研究人员积极参与，这将有助于实现这些目标是在波士顿大学的网络研究中心的机构。