Originally Posted by Scott Smith
It's a well known fact hosting sites with big files INCLUDING MICROSOFT throttle their downloads. Otherwise something as simple as a Service Pack roll out could pull their network to it's knees.
Yes, most all ISP's have a network management policy that kicks in during congested periods.
Here is the one I'm on:http://www.viasatresidential.com/wp-...012-Jan-13.pdf
ViaSat determines the nature of relevant traffic using deep-packet
inspection. More specifically, during periods of congestion:
The network gives high preference for VOIP, video/audio streaming/progressive downloads, and Internet browsing (both HTTP and HTTPS) applications (Level 1 Traffic).
The network gives second preference to email, small file attachments or transfers, and similar applications (Level 2 Traffic), which are less time-sensitive. In general, small files are files less than 50 MBs, although ViaSat may vary the size of file it considers to be small from time to time in order to best optimize network performance. Under congestion, the subscriber may experience somewhat lower speeds for Level 2 Traffic than for Level 1 Traffic transmitted during this time.
The network gives lowest preference to software updates, large file transfers, and similar applications (Level 3 Traffic) where, due to the longer duration of the overall transaction, longer delays are more acceptable than for the other levels of traffic (above). During congestion, subscribers may experience longer transfer times for large downloads.
That's why we've always recommended testing be done early in the day, before congestion sets in...once you've established a speed test site that delivers reliable results based on comparison of results from one test site to the other then you can then test with much smaller files during the evening hours when the network congestion is greatest ..
One of the big selling features of testmy.net for test engineers is it's the only reputable test site that allows users to select the file size used for their tests. A rule-of-thumb we always recommend for reliable speed tests is to use at least a x8 file size of the users' rated "up-to" speed package they pay for..example: if your package says speeds "up-to" 50mbs (mega-bits/sec) then you should select a file size of 50mB's (mega-bytes) to perform your test. A service with speeds "up-to" 12mbs would use at least a 12mB file size.
Network management and the ability to test that network are two different subjects...A network management engineer and a systems test engineer have different objectives when evaluating the overall performance on internet services..the two will rarely agree..