Internet access speed/units

[ABE]

I have a little difficulty with the units of measure for the internet access. I think my connection is 3 mbps using DSL.

When I download data my system:
1. starts at a very high speed of about 700 KBPS and gradually declines to about 235 KBPS. Why does the speed change?
2. is 235 KBPS the same as 2.35 mbps?
3. why am I not getting 3 mbps that I am paying for?
4. there are KBPS and kbps and mbps and ... why aren't the units consistent?

[jason]

It is normal for downloads to appear much faster at the start of a download, there are a few things happening here. Your browser will start to download at your RWIN set transfer rate. RWIN or TCP Receive Window is a buffer that determines how much data the receiving computer is prepared to get at one time. Your connection will then be reduced by your actual connection speed, which is 3Mbps - internet latency, distance from your ISP etc. Remember your connection will always be as fast as your slowest link. Depending on how much traffic a given website is receiving, or routing links along the way, there is lots of potential to slow your download speed.

Bandwidth units can be tricky. Capital letters are significant in determining wether you are dealing with bits or bytes. The small b means bits and the capital B means bytes.
Kilobits=Kb
Kilobytes=KB
Megabits=Mb
Megabytes=MB
and so on...
Typically bandwidth is measured in Kilobytes per second units. Kilobits is not very common anymore with high speed connections, but you would typically use Kilobits to describe transfer speeds on dial-up links e.g 56Kbps or 56Kb/s.
A typical DSL link would be 3Mbps Megabits per second which would be 300KB/s Kilobytes per second.

A common question is how come if I pay for a 3Mbps connection am I not getting it, well I hope this puts it all into prospective. You likely are getting it just not everywhere you go.

[admin]

If you are behind a proxy server then your connection is being modified which can account for what appears to be strange behavior but can be technically explained when you know what is happening. For instance when you first start your download the connection speed is being negotiated and may start off much higher than what your actually downloading at. In the background your proxy server is downloading the file at the fastest connection that it can establish with the remote site. The proxy server downloads the file to its local hard drive meanwhile it sends the file to your browser. Depending on how well your proxy is able to send the file to you, you may see a very slow speed such as 8 KB/sec for 10 min. and then it goes up to 700KB/sec for the last 2min. Some proxies will unpack the downloaded archive such as a zip,tar or rar file and "trickle" the file to your browser. The download may appear extremely slow, but in fact the proxy is downloading the file at a very fast rate but only giving you small amounts at a time. Once the proxy has completed downloading the file it will transfer the file to your browser at the fastest possible speed that can be established between your computer and the proxy.

[jason]

Check out this neat website

http://web.forret.com/tools/bandwidth.asp