The TCP slow start algorithm tries to increase the initial congestion window size exponentially until the slow start threshold is reached. The initial TCP start-up performance depends on accurate estimation of these two parameters. However, due to lack of information on network states initially, the standard TCP uses default values for these parameters.;If the initial congestion window size and the slow start threshold can be estimated accurately, it is possible for TCP to achieve higher initial bandwidth without congesting the network. For this purpose, we introduce a method to estimate the slow start threshold and the congestion window size using other TCP connections sharing the bottleneck links by taking advantage of fairness in TCP. Furthermore, when the information of other TCP connections sharing the same bottleneck links is not available, it is possible to approximate end-to-end available bandwidth with packet pair measurements which, in turn, is used to estimate the slow start threshold.;The standard TCP slow start, when delayed acknowledgement is enabled, can be slow since the growth rate of the congestion window is lower than when the delayed acknowledgement is not used. By way of inverted packet pairs and counting duplicate acknowledgements to increase the congestion window size during slow start, the advantage of delayed acknowledgement is retained during the congestion avoidance stage of TCP, while achieving almost the same performance in slow start as when delayed acknowledgement is not used.;Finally, our slow start algorithms can help to achieve higher initial bandwidth on a large delay bandwidth product path. This allows users of multimedia streaming applications or web browsers can have an improved user experience.
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