Implementing bandwidth management in a low-bandwidth environment

Abstract

The Internet has revolutionized the way organizations operate by providing them with the means for gathering and sharing of information. As the Internets popularity has increased, so has networked multimedia applications which place heavy demands on the network in terms of throughput and responsiveness. Under such loads, low capacity shared links fail to offer the quality of service expected by users. Examples of such links include those provisioned over geostationary satellites, shared Asymmetric Digital Subscriber Links (ADSL), or any over-subscribed link. In this project, we design and implement a bandwidth manager prototype for deployment in lowbandwidth links. We base our design on the bandwidth management needs of the Makerere University network where we propose to deploy the prototype. Our prototype design takes advantage of the distribution of flows by size on Internet links, 99% of which studies show to be short-lived. By limiting the consumption of bandwidth by the remaining 1% of flows which account for about 60% of the load on the said links, the prototype promises to significantly improve the quality of service for short-lived flows. After implementing the prototype using tools available on the Linux platform, we proceed to evaluate its design features on an isolated test bed. The test bed provides the environment required for the evaluation, including the capability of emulating links with high bandwidth products, as well as packet losses. Among the features we evaluate are traffic classification functionality, bandwidth allocation accuracy, bandwidth borrowing between classes and traffic prioritization.