[LG Revolution] Cybie257:
I'm starting a thread about this subject here because it isn't appropriate to continue a separate discussion where it all began.

There is a misunderstanding about Network/Data/Tethering Speeds and I would like to explain it the best I can.

If you Are using the root tether apps, you are connecting at 54Mbps.

- 54Mbps at 40% capacity is around 21.6Mbps

- 21.6Mbps is approximately 2.7 MB (MegaBytes) per second

- 21.6Mbps is also the MAX throughput you should expect

- With overhead and other factors, generally you will get approx 65-70% of that throughput that is usable data (OSI Model Overhead)

- 65% of 21.6Mbps = 1.755 MB/Sec Actual Speed Downloading a File, or 14Mbps

Why, then, would I get readings as high as 20-22Mbps via Speedtest Sites? Because that is RAW data (Little Overhead - OSI Model) and providing you with MAXimum Throughput readings on a 54Mbps Maximum Bandwidth Link.

Bandwidth and Throughput are Totally different, though mistakenly thought of as the same.

If your connecting via the USB Tether option, you are connecting at 480Mbps (USB 2.0 Standard), but you may notice via Windows 7, that the LinkSpeed is reading 412Gbps, which is obviously wrong, so going with 480Mbps for this explanation.

- 480Mbps at 40% capacity is around 192Mbps

- 192Mbps is approximately 24 MB (MegaBytes) per second

- 192Mbps is also the MAX throughput you should expect

- With overhead and other factors, generally you will get approx 65-70% of that throughput that is usable data (OSI Model Overhead)

- 65% of 192Mbps = 15.6 MB/Sec Actual Speed Downloading a File, or 124.8Mbps

If your network speed is at 21.6Mbps or less (SpeedTest directly on the phone), you wouldn't necessarily see any significant speed differences between the phone/USB Tether/WiFi Tether Methods.

If your phone, such as mine, is getting Speeds as fast as 40.5Mbps Down, then yes, you would have quite a difference between USB Tether and Wifi Tether speeds on your computer.

40.5Mbps = 5.06 MB/Sec File Transfer Rate. Because the capacity of the USB Tethering is way beyond the Max Network Rate (Phone), there is theoretically no Loss in speed. 124.8Mbps - 40.5Mbps = 84.3Mbps. There is over 84.3Mbps of spare throughput available.

So, for those who have argued that there shouldn't be that much of a difference between Wifi Tethering and USB Tethering, learn about overhead, bandwidth, througputs, and the OSI model. It's factual information and will allow you to understand more about the difference in speeds on any network. Using the methods of calculation above, you will always be able to know what to expect when transferring a file to and from the internet, or even another computer. Just keep note of the MAX output numbers. There will always be something that gets in the way. The Max Speed on the Freeway might be 65MPH, but when traffic is very heavy, you might be down to 20MPH. Same goes for number of computer on the information highway.

A good detailed Bandwidth Calculator can be found at: http://web.forret.com/tools/bandwidth.asp?speed=14&unit=Mbps

After looking at the preview of the post, I already know what I should expect as a question about bandwidth/throughput via USB mode.

Question: If you show the MAX USB Throughput to be 15.6MB/Sec, then why can I transfer files to and from phone and other USB Devices at 22+MB/Sec?

Answer: USB VS Ethernet. The USB Is actually being converted to an Ethernet connection for the purpose of Network Data and not File Data.

-Cybie

PS. It's late and I'm tired. So, if something is not clear, or it appears I goofed up something bad here, please do not hesitate to ask questions. I would like this to be as clear as possible as to why I answered other posts the way I did. And to do it here in a General thread in order to not go off-topic in a Developer Thread.