Resources

Bandwidth Speed Test

The DSCI Speed Test will help you assess your current line throughput or Internet connection speed. To better understand the test results, be sure to read through the Understanding Internet Bandwidth section below.



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Understanding Internet Bandwidth

About Bandwidth

Internet bandwidth is, in simple terms, the transmission speed or throughput of your connection to the Internet. However, measuring bandwidth can be tricky, since the lowest bandwidth point between your computer and the site you’re looking at determines the effective transmission speed at any moment.

Three factors outside of your computer control how quickly you can view Web pages or download information:

  • The Internet bandwidth between your computer and the site you’re viewing.
  • The round-trip time between your computer and the site you’re viewing.
  • The response time of the site you’re viewing.

The Internet changes from one moment to the next in ways that are impossible to predict. You cannot expect to see the same bandwidth value every time you measure it. Furthermore, you cannot expect to see the full nominal speed of your connection for your bandwidth measurement because there are always delays somewhere.

To get the best picture of your Internet bandwidth, test several times. Also test at different times of the day: Your bandwidth measurement at 7 AM may be much better than your bandwidth measurement at 10 PM.

Determining Bandwidth Availability

How do you translate Kilobytes (KB) to kilobits (kb)?

First, let’s explain how you can count the passage of information that we refer to as “bandwidth.” In the simplest of forms, data is simply 1s and 0s; these are referred to as bits. This is how we refer to the speed of T-1 connections. For example a 384kbps connection represents a 384000 bit per second connection. When using a commercial OS and browser you will often get a download speed which is measured in “KBps” (kilo-bytes-per-second). In order to get “kbps” (kilo-bits-per-second) you have to perform a little math. There are 8 bits in a byte and 1024 bytes in a kilobyte. Thus 384000 bits = 48000 bytes = 46.875 Kilobytes.

Why the difference? Communications speeds are usually measured in bits per second, while many computer operations are measured in bytes per second.

What else consumes bandwidth?

It is impossible to send “pure” information over a digital line. This is due to the fact that the transmitted data is encapsulated in shells (frames) to ensure the integrity of the information, as well the additional protocols necessary to route the data over Ethernet, ATM, and other networking protocols.

This means about 8-10% of bandwidth is taken up by routing overhead. This overhead brings down the bandwidth in our example above to about 42Kbps on a perfect connection in which bandwidth is saturated and there are no delays on the Internet.

Real world performance predictability is found by dividing your connection speed (kbps) by 10 to arrive at typical speeds (in Kbps). Example: 604/128kbps / 10 = 60.4/12.8 Kbps.