CAREER:The Internet Congestion Manager

近年来，互联网流量模式和应用迅速发展，网络拥塞正成为一个极其重要的问题。虽然因特网的传输协议TCP结合了拥塞控制机制，并且迄今为止对因特网的稳定性负有主要责任，但两个有问题的趋势威胁着这种情况： 并发流： 一些应用程序的特点是发送方和接收方之间有多个并发流。如今，这些流彼此竞争网络资源，在网络上表现得过于激进，并且彼此不共享有关网络的信息。 缺乏适应性： 越来越多的应用程序使用基于UDP的流没有健全的拥塞控制，因为他们不需要TCP提供的可靠，有序的服务。今天，他们不了解或适应良好的悬挂网络条件。不幸的是，目前的协议体系结构不提供足够的支持。 受这些趋势的推动，NSF的CAREER提案从终端系统的角度重新审视了互联网拥塞管理，并提出了一种围绕拥塞管理器（CM）构建的新架构。CM维护跨流的网络统计数据，编排由鲁棒控制原则管理的数据传输，并使用拥塞控制器、流检测器和反馈探测器从接收器获得反馈。它还为应用程序导出了一个简单而强大的API，以了解网络状态并调整其数据传输以获得最佳性能。 该提案的研究重点包括：（i）网络架构，涉及CM基础设施和API的设计和部署，（ii）使用数学和模拟技术分析 关于控制质量、因特网性能的空间稳定性、以及网络性能参数的时间稳定性和缓存潜力的拥塞反馈，（iii）算法，用于决定哪些流共享拥塞状态，用于新的拥塞控制技术，以及用于在没有接收器反馈的情况下使拥塞控制参数老化，（iv）在发射机和接收机之间传送探测和反馈的协议，并允许在数据传输中反映用户偏好，（v）CM和包括Web和实时会议应用在内的若干应用的实现，及（vi）在广域互联网上部署CM及其应用程序，以进行性能试验。 如果成功，这项研究有可能从根本上改变终端主机的网络架构，并大大改善设计和 互联网应用的实现，形成未来互联网拥塞管理的基础。随着这项工作的成熟，预计将对一些CM协议和API进行IRTF（互联网研究任务组）和IETF（互联网工程任务组）批准的标准化，并与流行服务器操作系统的供应商进行讨论，以探讨技术转让问题。本研究的主要预期结果是详细设计，分析和评估CM架构的内部算法，拥塞分析，自适应API，CM协议，在Linux操作系统中的参考实现，以及几个应用程序。由此产生的软件将在标准的麻省理工学院下免费提供。版权所有. 这份提案中的教育计划包括三个部分：（i）课程开发，在本科生和研究生阶段引入两门新的网络课程，重点放在基本原则和实际问题上，（ii）本科生研究，利用麻省理工学院。的UROP计划，并涉及本科生在各个方面的建议的研究，和（iii）教学理念，强调科学方法和实验计算机科学在本科教育，通过设计几个动手实验任务，并广泛使用模拟和可视化讲座相同的工具，是车辆的研究提出了这里。

Internet traffic patterns and applications have been evolving rapidly in recent years and network congestion is becoming a problem of extreme importance. While the Internet's transport protocol, TCP, incorporates congestion control machinery and has largely been responsible for the stability of the Internet to date, two problematic trends threaten this situation: Concurrent flows: Several applications are characterized by multiple concurrent flows between sender and receiver. Today, these flows compete with each other for network resources, prove overly aggressive on the network, and do not share information about the network with each other. Lack of adaptation: An increasing number of applications use UDP-based flows without sound congestion control because they do not need the reliable, in-order service provided by TCP. Today, they do not learn about or adapt well to hanging network conditions. Unfortunately, current protocol architectures do notprovide adequate support for this. Motivated by these trends, this NSF CAREER proposal takes a fresh look at Internet congestion management from an end-system perspective and proposes a new architecture built around a Congestion Manager (CM). The CM maintains network statistics across flows, orchestrates data transmissions governed by robust control principles, and obtains feedback from the receiver, using a congestion Controller, Flow Scheduler, and Feedback Prober. It also exports a simple yet powerful API for applications to learn about network state and adapt their data transmissions to obtain the best possible performance. The research thrusts of this proposal include: (i) network architecture, involving the design and deployment of the CM infrastructure and API, (ii) analysis using mathematical and simulation techniques of the impact of congestion feedback on control quality, of the spatial stability of Internet performance, and of the temporal stability and potential for caching of network performance parameters, (iii) algorithms, for deciding which flows share congestion state, for new congestion control techniques, and for aging congestion control parameters in the absence of receiver feedback, (iv) protocols to communicate probes and feedback between senders and receivers and allow user preferences to be reflected in data transmissions, (v) implementation of the CM and several applications including Web and real-time conferencing ones, and (vi) deployment of the CM and its applications in the wide-area Internet to conduct performance experiments. If successful, this research has the potential to fundamentally change the network architecture of end-hosts and greatly improve the design and implementation of Internet applications, forming the basis for congestion management in the future Internet. As this work matures, IRTF- (Internet Research Task Force) and IETF-sanctioned (Internet Engineering Task Force) standardization of some of the CM protocols and API are expected, as are discussions with vendors of popular server operating systems to explore technology transfer issues. The major expected results of this research are a detailed design, analysis, and evaluation of the CM architecture the internal algorithms, analysis of congestion, the adaptation API, the CM protocol, a reference implementation in the Linux operating system, and several applications. The resulting software will be made freely available under the standard M.I.T. copyright. The education plan in this proposal consists of three components: (i) curriculum development, to introduce two new courses in networking at the undergraduate and graduate levels, focusing on fundamental principles as well as practical issues, (ii) undergraduate research, tapping into M.I.T.'s UROP program and involving undergraduate students in various aspects of the proposed research, and (iii) a teaching philosophy emphasizing the scientific method and experimental computer science in undergraduate education, by designing several hands-on experimental tasks and using simulation and visualization extensively in lectures the same tools that are the vehicles for the research proposed herein.