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24th August 2011 at 09:57 #67010mXaGuest
I am trying 2 methodologies for data sessions
1- Single file download
2- Multiple files download at same time
Throughput is higher for case 2 than that of 1 with a big percentage. Does anyone know the reason for this variance?
mXa24th August 2011 at 13:07 #67011SHELDONGuest
I think the difference is as a result of downloading a smaller file in case 1. In case 2, the combined effect of downloading multiple files is equivalent to downloading a big file.
In order to correctly measure throughput, you need to download a big file (eg 20Mb). Otherwise, the throughput will be fictitiously low. This is because the throughput starts increasing from zero(just before u start downloading), and if the file is small, it will finish downloading before you achieve the maximum throughput.
Hope this helps
Sheldon26th August 2011 at 21:21 #67012mXaGuest
Thanks Sheldon for ur reply. What u r saying makes sense, I will try it.
There is another thing in my mind. What are the things that delay me from reaching my maximum throughput ? (if i assumed downloading a large file)
mXa26th August 2011 at 21:48 #67013pixGuest
are you in EGPRS or in 3G ? HSDPA ?
the reason for slow transfer at the beginning is that the system is being cautious : it assumes you have bad radio quality so it encodes the signal with high % of protection + it modulates the signal with a robust modulation.
pix27th August 2011 at 11:30 #67014mXaGuest
I am on 3G. I checked TCP window value and it is in an adequate range.
What u r saying implies for both 2G and 3G ? Can I change that % of protection to make a faster start ?
mXa27th August 2011 at 22:08 #67015mXaGuest
I meant HSDPA in 3G.
Thx10th September 2011 at 23:06 #67016mXaGuest
what is the deal with protection bits ?