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Sometimes there's a need to download multiple files from somewhere. The protocol I'm specifically interested in is HTTP, however this question is also relevant to FTP or any other non-P2P protocol for transferring files.

Assuming the server (for example, Rapidshare) has unlimited bandwidth (relative to the client), and the client has a standard internet connection of X Mb/s, will it be faster to download multiple files at the same time (how many?) or download them as a queue, one after the other?

Which parameters will change your answer? Will it be different for different internet connection speeds? What about home/work LAN?

yellowblood
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2 Answers2

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It depends on what the rate-limiting factor is. Most of the time, the end-user's Internet bandwidth is the limiting factor, and then it doesn't matter. But if, for example, the limiting factor is competing with other traffic, then more streams will tend to get a larger share of that traffic. If the limiting factor is packet loss, then more streams may be a bit more resistant (as a drop on one stream won't affect traffic on the others).

David Schwartz
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I have Firefox browser with Down Them All extension, running in Ubuntu. Every additional file download increases the average speed and decreases the total time to completion. Six simultaneous downloads of roughly the same size can complete in 1/6 the elapsed time of a single download, if they all complete within a few seconds of each other. If 5 of them finish at 3 minutes, and 1 is not yet finished, the time to completion of that 1 will increase rapidly to as much as 20 minutes. I have found that repeatedly running an internet speed test at the same time as a single download will greatly decrease the time it takes to complete that download.

rjeff
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