ITR: Active Queue Management for Scalable Network Services: Theory and Internet Practice

ITR：可扩展网络服务的主动队列管理：理论与互联网实践

• 批准号: 0082870
• 负责人: Kevin Jeffay
• 金额: $ 45.19万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0082870&HistoricalAwards=false
• 关键词: ITR; Active; Queue; Management; Scalable

Two of the largest issues facing the Internet today are the problems of (1) providing quality-of-service to applications that require some form of "guarantee" of bandwidth availability and/or end-to-end delay, and (2) the problem of avoiding congestion between traditional best-effort flows. Packet scheduling has been the mechanism traditionally used for quality-of-service guarantees while end-system adaptations in the transport layer have been the dominant form of congestion control. Typically, the problems of congestion control and quality-of-service have been addressed as largely independent concerns and separate mechanisms have been developed for each . The essence of this project is to study the interplay between congestion control and quality-of-service and the mechanisms that have been employed for realizing each. The starting point is an investigation of using active queue management(AQM) techniques in network routers to provide both congestion control and quality-of-service for IP flows. Active queue management refers to the practice of manipulating the queue of packets at an outbound network interface on a router to bias the performance of network flows. For example, discarding packets from the queue is an active queue management mechanism that is used in the RED (random early detection) congestion avoidance mechanism. There does not yet exist any fundamental theoretical understanding of how individual AQM mechanisms effect the performance of network flows. From the perspective of Internet service providers this problem is compounded by the fact that there is little, if any, understanding of how AQM mechanisms can be tuned to realize specific performance goals. The impact of AQM mechanisms on broader measures of network performance is unknown because a framework for analyzing AQM performance does not yet exist. This is in contrast to other approaches for quality-of-service such as packet scheduling. Packet schedulers have been carefully analyzed and frameworks exist for computing bounds on performance metrics such as delay, delay-jitter, packet loss, etc. The main goal of this project is to develop the theoretical underpinnings and engineering principles to guide the construction and deployment of AQM for the Internet. This requires an analytic and empirical study of AQM mechanisms for the purpose of understanding the costs, benefits, and scalability limitations of using AQM for congestion control and quality-of-service. The project also contributes to the overall understanding of principles of resource management in routers. In addition, novel AQM schemes that provide new, scalable solutions for quality of service and congestion control are developed.Specific objectives include the following: 1. Develop an analysis framework for understanding the performance of AQM mechanisms. A novel aspect is consideration of both network-centric performance metrics such as link utilization, and end-systemor user-centric measures such as response time. 2. Develop and analyze novel AQM and hybrid AQM-packet scheduling schemes that realize a spectrum of quality-of-service and congestion control services. A key contribution here is a demonstration of the costsand benefits of using packet scheduling v. AQM for scalable implementations of services. 3. Demonstrate the effectiveness of the AQM schemes through a case study in managing a research network and supporting an advanced, real-time, distributed-virtual-environment application. The results of this project can have a significant impact on the evolution of the Internet to support new levels of service quality and control congestion while ensuring scalability for very large numbers of users and devices.

当今因特网面临的两个最大的问题是：（1）向需要某种形式的带宽可用性和/或端到端延迟的“保证”的应用提供服务质量的问题，以及（2）避免传统尽力而为流之间的拥塞的问题。分组调度一直是传统上用于服务质量保证的机制，而传输层中的端系统自适应一直是拥塞控制的主要形式。典型地，拥塞控制和服务质量的问题已经被作为很大程度上独立的关注点来解决，并且已经为每一个开发了单独的机制。 这个项目的实质是研究拥塞控制和服务质量之间的相互作用，以及实现每一个机制。出发点是使用主动队列管理（AQM）技术在网络路由器提供拥塞控制和服务质量的IP流的调查。主动队列管理是指在路由器上的出站网络接口处操纵分组队列以使网络流的性能发生偏差的做法。例如，从队列中丢弃分组是在RED（随机早期检测）拥塞避免机制中使用的主动队列管理机制。 目前还没有任何基本的理论理解，如何个别的AQM机制的影响网络流的性能。从互联网服务提供商的角度来看，这个问题是复杂的事实，有很少，如果有的话，了解如何AQM机制可以调整，以实现特定的性能目标。AQM机制对更广泛的网络性能测量的影响是未知的，因为分析AQM性能的框架还不存在。这与数据包调度等其他服务质量方法形成鲜明对比。已经仔细分析了分组转发器，并且存在用于计算性能度量（诸如延迟、延迟抖动、分组丢失等）的界限的框架。 这个项目的主要目标是发展的理论基础和工程原则，以指导建设和部署的AQM的互联网。这需要一个分析和实证研究的AQM机制，了解的成本，效益和可扩展性的限制，使用AQM拥塞控制和服务质量的目的。该项目还有助于对路由器资源管理原理的全面理解。此外，新的主动队列管理方案提供了新的，可扩展的解决方案的服务质量和拥塞控制的发展。具体目标包括： 1.开发一个分析框架来理解AQM机制的性能。一个新颖的方面是考虑以网络为中心的性能指标（例如链路利用率）和以终端系统或用户为中心的指标（例如响应时间）。 2.开发和分析新的AQM和混合AQM分组调度方案，实现一系列的服务质量和拥塞控制服务。这里的一个关键贡献是使用分组调度v. AQM的服务的可扩展实现的成本和好处的示范。 3.通过一个案例研究来证明AQM方案在管理研究网络和支持先进的、实时的、分布式虚拟环境应用中的有效性。 该项目的结果可能会对互联网的发展产生重大影响，以支持新的服务质量水平和控制拥塞，同时确保大量用户和设备的可扩展性。