Internet Congestion Control: Design, Modeling, and Analysis

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

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.