Homehow ToHow internet speed tests work and how accurate they are

How internet speed tests work and how accurate they are

Do you have an ADSL or VDSL connection on the internet? Are you sure your provider offers you what you pay for? If you want to see what you really got when you signed up for the internet connection, read the article below.


If you are looking for the new VDSL of 50 Mbps it is better to check first if you really have that speed. Internet speed tests are a quick way to see how fast your internet connection is.

Internet service providers promise "up to" a certain speed, measured in optimum conditions. But if you want to know how fast or slow your connection is, a speed test is a must.

What is Internet Speed ​​Testing?
A speed test is the best way to get an idea of ​​how fast your connection is at that time.

The service you connect to the internet often limits download and upload speeds based on the financial package you chose, local congestion, any settings you have imposed, and so on.

The most interesting point of a connection is the promises of the Internet Service Provider (ISP). These almost always include the phrase "up". This policy trick from the ISP gives him the right to claim that if you promised "up to 24 Mbps" and you only receive 15 Mbps, then the company keeps its promise. But if you make metrics and see 10 Mbps, then you are not getting what you pay for and it is time to call your ISP.

Of course ADSL and VDSL connections have limitations and multiple factors that affect speed, but the self-respecting ISP takes care of setting up DSLAM in each square and not overloading them in motion. DSLAM is a multiplexer, located within your neighborhood's KAFAO, which assumes the concentration of the signals from the entire neighborhood into a single complex signal through a process called multiplexing. From there, the data is sent to your ISP that has given you access to the internet.


A speed test measures the ping, and the speed of up and down. The measurement of the latter two is necessary because most ISPs offer separate download and load rates. Typically, the download speed is the one shown in the brochures, as it is the fastest, but if you go into the details of your connection you will see that the ISP usually determines a slower shipping speed for each financial package.

For example, our local ISP offers an ADSL connection packet at 24 Mbps download speed, but the 1 Mbps download speed.

How does a speed test work?
There are three ways to do a speed test of your internet connection. THE first way and the easiest, is to go to an online service through your browser. There are several such as speedtest.net, fast.com, testmy.net, broadbandspeedchecker.co.uk, speed.io and a whole lot more.

Ο second way is to use an ftp application and download a large file via an ftp connection, while at the same time you will see your speed through a download manager. And here there are many ftp servers that offer this feature, such as Cosmote, Nova (Forthnet), the National Technical University of Athens., h Hetzner.de etc.

Ο third way is to provide your router with such a speed gauge, where you enter it through a browser to run it.


When you start a speed test, many things happen. First, the test service determines your location and the nearest test server to you. It is important to test your internet speed with your nearest test server, as the speed that your ISP promises refers to ideal conditions. In fact, if your ISP has a speed test server then you should measure your speed on it.

Some versions, such as the Speedtest.net of Ookla, have the option to change the server. When the speed test is started, a simple ping signal is sent to the server and he answers. Send and reply time is measured in milliseconds (ms). The smaller the number the better.

After the ping has finished, the download test begins. Your computer opens multiple connections to the server and tries to download a small number of data. At this point, two things are measured: how long the packet of data had to download and how much network media was used.

If the testing program detects that your computer has more connectivity, it opens more connections to the server and downloads more data. The idea is to upload your internet connection to see how much it can accomplish by doing simultaneous tasks.

Imagine your internet service as a high-speed motorway. Opening additional links is like adding more lanes to the highway. The speed limit has not changed, but more cars can go from the same space at a faster rate. So the 50 car will arrive earlier using a four-lane motorway than two lanes.

Once the service finds that it has the right connections to test your internet service, it downloads additional pieces of data, counts the amount received during the time allocation, and lists the download speed, with the unit of measure Mbps, which means Megabytes per second . It essentially tells you in a time equal to one second how many megabytes it managed to download.

The load test follows. It is essentially the same procedure as the receiving test, but vice versa. Instead of downloading data from the server to your computer, your computer uploads data to the server.

For more detailed technical information, read on analysis of Speedtest.net about how it works.

Are speed tests accurate?
Although speed tests sound like something simple, it's actually much harder to accurately measure how fast your internet connection is.

Watch this first step of the process: selecting a test server. Often the nearest server can be incredibly close, maybe even in the same city. This proximity is an optimal situation, with the data not having to travel far. Businesses know that proximity makes a difference, and that's why some, like Netflix, use a broad and global customer service network to bring the data as close as possible to you.

But the whole internet is not near you. Many of these are on remote computers, sometimes in another city or in another country. So while the speed test can show incredibly fast traffic, you may find that downloading a program is too slow if the server hosting the data is too long. Based on this common scenario, your test results may show you a faster performance than actual usage.

The difference in server locations is the reason why you might see different speed results when you try different speed test services, such as the Ookla, Netflix ή Google. See the results we received from 4 different services that we were targeting on different servers.

Service Ping (ms) Download (Mbps) Upload (Mbps)
Speedtest.net (to Cosmote) 28 13,02 0,77
Fast.com (Netflix) 32 12,00 0,74
Googlefiber.net (Google) 647 11,60 0,55
Broadband (to Frankfurt) 356 12,18 0,81

Your ISP can also offer you a speed test such as Cosmote the Cyta, Forthnet. Vodafone used to have a ftp connection for speedtest, but today its page has been removed. Or, if your provider is not listed, you can select it ftp of the National Technical University of Athens.

However, in reality you should not rely on speed test results produced by your ISP. These tests are optimized for ideal conditions using nearby servers. This means you will get a faster result than what will give you a Netflix or Google speed test.

It's a good method if you just want to boast about how wonderful your ISP is (or that's the idea), or make sure your ISP delivers the promising internet speed, but it's a bad way to get a real speed idea your. See what speeds Speedtest.net has shown to us for different servers that exist both in Greece and abroad.

Speed ​​measurements with Speedtest.net
Server - Country  Ping (ms) Download (Mbps) Upload (Mbps)
To Cosmote 28 13,02 0,77
To Vodafone Greece 27 12,50 0,77
To AT&T (New York - USA) 160 12,21 0,75
To i3D (Tokyo - Japan) 336 12,26 0.54


To second step of the control process, your computer attempts to open additional connections and maximize the use of your network. If you already have your network loaded, the speed test can not fully utilize your resources.

If you try to run a speed test while watching streaming a Netflix movie or downloading a large update, for example, your results will be lower than the test results you would have done without performing the above tasks.

How you are connected and which devices you test, also affect the results. An ethernet-connected computer should have a faster speed result than a tablet connected to Wi-Fi, because Wi-Fi is generally slower than the ethernet. You may find that the results differ on different devices, even if they use the same connection.

How to get the most accurate results
Getting accurate results depends on what you plan to measure. Do you want to see if your internet service provider really provides the promised speeds that your contract says?

Then go for optimal, ideal conditions. Use a device connected to the ethernet (wired, not wireless), select the test server closest to you, and stop anything that can consume your Internet connection.

It would be better to restart your router before performing a speed test. If your router has built-in speed control, use it instead of doing it via an online service. This removes some steps the process must go through and so the results will be better.

However, if you want to see results that are closer to real-world performance, use a browser or application. Bypassing the test of your router, you will be able to select a server that is further away. Try with Google you theoretically visit it quite often.

Ultimately, regardless of the methodology or the way you measure it, you will not get an absolutely accurate result. However, you can satisfy your curiosity by controlling the speeds promised by your ISP.

In a world without fences and walls, who needs Gates and Windows