And download managers/accelerators can detect this and apply the segmented transfer technique across multiple servers, allowing the downloader to get more collective bandwidth delivered to them. In some cases it is possible to find multiple servers that provide the same resource, sometimes a single DNS address round-robins to several IP addresses, or a server is part of a mirror network of some kind. Hence, people who live near by are not so likely to need to do a segmented transfer, but people who live in far away locations are more likely to benefit from going crazy with their segmentation. However, this limitation appears to be "per connection", so multiple TCP connections to a single server can help mitigate the performance hit of the high latency ping time. There's this annoying thing called bandwidth-delay-product where the size of the TCP buffers at either end do some math thing in conjunction with ping time to get the actual experienced speed, and this in practice means large ping times will limit your speed regardless how many megabits/sec all the interim connections have. Secondĭownload accelerators like to break a single transfer into several smaller segments of equal size, using the same start-range-stop mechanics, and perform them in parallel, which greatly improves transfer time over slow networks. Thus, if you have an intermittent connection, the aggregate transfer time is greatly lessened. This means if something dies mid transaction ( ie: TCP Time-out ) it just reconnects where it left off and you don't have to start from scratch. Acceleration is multi-faceted FirstĪ substantial benefit of managed/accelerated downloads is the tool in question remembers Start/Stop offsets transferred and uses "partial" and 'range' headers to request parts of the file instead of all of it. You'll get a more comprehensive overview of Download Accelerators at wikipedia.
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