Internet Congestion Control: Design, Modeling, and Analysis

未来的高速网络将比任何现有网络都要大得多，也更复杂。应用程序、中间件和传输协议以及路由器/交换机资源管理算法的多样性和互动性将使这些网络的设计、开发、控制、管理和评估成为一项异常困难的任务。网络控制体系结构中最关键的组件之一就是拥塞控制。到目前为止，互联网一直依赖于TCP的大多数变体中存在的加性增加、乘性减少机制来进行拥塞控制。然而，人们越来越认识到，未来的高速网络需要能够与TCP共存的新的拥塞控制机制。这是由于提供异类应用需求的需求日益增加，并且因为许多未来的应用将依赖于多播。目前，TCP拥塞控制不足以处理异构性或组播。还需要一种更好的方法来建模和分析TCP性能和即将到来的拥塞控制算法的性能。尤其需要开发这样的方法来评估混合的TCP会话和未来的非TCP会话的行为，以避免在部署它们时出现任何令人不快的意外。该提案描述了两个主要领域的新的基础研究：(1)基于公式的拥塞控制。研究人员提出了一种新的基于速率的拥塞控制方法。该项目引入了一种基于公式的方法，其中会话监控其端到端丢失率并相应地调整其传输速率。该研究展示了如何使用该方法来构造一个对TCP友好的速率控制算法，并概述了该方法的研究议程，以探索和利用该方法支持多播应用和支持异类应用的潜力。(2)拥塞控制算法的性能评价。研究人员提出了基于随机微分方程组的不同拥塞控制算法的性能评估研究。这项研究在理解、设计和分析下一代传输协议所需的拥塞控制算法方面迈出了重要的一步。

Future high-speed networks will be significantly larger and more complex than any existing network. The variety and interaction of the applications, the middleware and transport protocols, and the router/switch resource management algorithms will make the design, development, control, management and evaluation of these networks an exceptionally difficult task. One of the most critical components in the network control architecture is that concerned with congestion control. The Internet has relied till now on the additive increase, multiplicative decrease mechanism, found in most variations of TCP, for congestion control. There is increasing recognition, however, that new congestion control mechanisms, which will be able to coexist with TCP, are needed in future high speed networks. This is due to the increasing need to provide for heterogeneous application requirements and because of many future applications will rely on multicast. As is, TCP congestion control is inadequate for handling either heterogeneity or multicast. There is also a need for a better methodology for modeling and analyzing the TCP performance and the performance of coming congestion control algorithms. The development of such a methodology is especially needed to evaluate the behavior of a mix of TCP sessions and future non-TCP sessions so as to avoid any unpleasant surprises as they are deployed. This proposal describes new and fundamental research in two broad areas: (1)Formula-based congestion control. The researcher proposes research on a new approach to rate-based congestion control. The project introduces a formula-based approach in which a session monitors its end-end loss rate and adapts its transmission rate accordingly. The research shows how this can be used to construct a TCP-friendly rate control algorithm and then outline a research agenda for exploring and exploiting the potential of this approach to support multicast applications, and to support heterogeneous applications. (2)Performance evaluation of congestion control algorithms. The researcher proposes research on the performance evaluation of different congestion control algorithms based on the use of stochastic differential equations. This proposed research represents a fundamentally important step in the understanding, design, analysis of congestion control algorithms needed by the next generation transport protocols.