With the increasing popularity of handheld devices and wireless local area networks (LANs), real-time applications such as Internet telephony are poised to become ubiquitous. While there has been a substantial amount of research on quality of service problems in the Internet, most end-to-end bandwidth allocation approaches, such as RSVP, have had limited success due to scalability and deployment issues. Starting with the observation that reserving bandwidth in the Internet backbone requires substantial infrastructure support, but reserving bandwidth in the first hop does not, we only focus on the first-hop reservation. We evaluate several first hop allocation schemes and determine their effectiveness in improving end-to-end performance. Since utilization of the reserved first-hop bandwidth depends on the remaining Internet path throughput, we characterize this throughput using traces collected from a popular Web site. Our analysis shows that different clients experience widely different throughputs, and that a significant portion of the clients receive very low throughput (e.g. less than 20 Kbps). We then evaluate several bandwidth allocation schemes for various congestion scenarios. Our results show that the scheme which takes into account of both the application data rate and available Internet path bandwidth yields the best performance. Moreover, the scheme performs even better if it adapts to the changing path properties. We discuss how path bandwidth can be measured without active probing, how frequently it needs to be measured, and how this measurement is incorporated into the first-hop bandwidth allocation algorithm.
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