What Is A Speed Test And How Do They Work

Terminology

Packet
is the unit of data that is routed between an origin and a destination on the Internet or any other packet-switched network. What does that mean? a packet is a container of data. To learn More
Data
is information that is translated into a binary form. To learn More
Latency
is an expression of how much time (usually in milliseconds) it takes for a packet of data to get from one designated point to another. To learn More
Jitter
is the variation in latency as measured in the variability over time of the packet latency across a network. What does that mean? Jitter is basically a way to measure the difference that it takes multiple packets to reach their destination. To learn More
Ping
is a small program that will send a packet of data to a source and measures the time it takes for the packet to return or echo. To learn More

Contrary to popular opinion all speed tests are not the same. Depending on what speed test you use, they all have different software to perform their test, and they all have different locations at which they perform the speed test.

What a speed test does with a web browser or App is connect to a server, which then measures the latency to that site using a ping. Then it either downloads or simulates a download of a file of a known size and measure the time it takes to receive all of the packets sent, that will show it's download speed, it will then upload or simulate the upload of that file and measure the time it takes to receive all of the packets sent by your computer. That will determine your upload speed. To learn more

While the process sounds simple, all speed test companies will accomplish the desired test a bit differently and at different locations, let's take a look at why a location would make a difference. Let's take a look at three different companies that offer speed tests;
Company ABC is located in Brisbane Australia and offers free speed test to their servers.
Company XYZ is located in Seattle Washington and offers free speed test to their server.
DFN which is your Internet Service Provider offers free speed tests to their server
As described above the test sends a ping from their server to your computer and listens for an echo, that communication will travel from their server to your computer and return. The distance from your computer to the server at Company ABC is approximately 7222 miles. Resulting in that packet traveling from their server to your computer and returning to their server. Therefore that packet will have traveled 14444 miles to complete its latency or ping test, that will obviously take some time to travel that far which is about twice the distance between the north and south pole.
The distance from your computer to the server at Company XYZ is approximately 250 miles so that packet must travel from their server to your computer and return to their server, therefore that packet will have traveled 500 miles to complete its latency or ping test, that is approximately the distance from your home to San Francisco.
The distance from your computer to our server is definitely much shorter than either of the above name companies.
Now, why would that make a difference? First, we would need to understand how that packet would get from your computer to their server and back. To go from your computer to Company ABC in Austraila that packet would go from your computer through your router to our equipment and then through multiple switches on our network to our router. From there it would travel through our upstream provider, through multiple switches on their network to their upstream provider, through multiple different companies until it finally reaches the destination all the way on the other side of the planet. After all of that, it then has to turn around and come all the way back. The process would be the same for company XYZ although quite a bit shorter.
To use our speed test the packet would leave your computer, through your router, to our equipment and through our network to our server and return. As you can see there is much less time and distance that communication needs to travel.

Does DFN offer free speed test? Yes Click Here