Technical Report Number
With the explosion of the World Wide Web, the Internet infrastructure faces new challenges in providing high performance for data trafﬁc. First, it must be able to pro-vide a fair-share of congested link bandwidth to every ﬂow. Second, since web trafﬁc is inherently interactive, it must minimize the delay for data transfer. Recent studies have shown that queue management algorithms such as Tail Drop, RED and Blue are deﬁcient in providing high throughput, low delay paths for a data ﬂow. Two major shortcomings of the current algorithms are: they allow TCP ﬂows to get synchronized and thus require large buffers during congestion to enable high throughput; and they allow unfair bandwidth usage for shorter round-trip time TCP ﬂows. We propose algorithms using multiple queues and discard policies with hysteresis at bottleneck routers to address both these issues. Us-ing ns-2 simulations, we show that these algorithms can signiﬁcantly outperform RED and Blue, especially at smaller buffer sizes. Using multiple queues raises two new concerns: scalability and excess memory bandwidth usage caused by dropping packets which have been queued. We propose and evaluate an architecture using Bloom ﬁlters to evenly distribute ﬂows among queues to improve scalability. We have also developed new intelligent packet discard algorithms that discard packets on arrival and are able to achieve performance close to that of policies that may discard packets that have already been queued. Finally, we propose better methods for evaluating the performance of fair-queueing methods. In the current literature, fair-queueing methods are evaluated based on their worst-case performance. This can exaggerate the differences among algorithms, since the worst-case behavior is dependent on the the precise timing of packet arrivals. This work seeks to understand what happens under more typical circumstances.
Kantawala, Anshul and Turner, Jonathan S., "Improving the Performance of Internet Data Transport" Report Number: WUCSE-2005-11 (2005). All Computer Science and Engineering Research.