Domain Name System (DNS) is a system or database that manages domain names and similar networks. Each ISP (Internet Service Provider) manages DNS from their servers and DNS are usually needed for surfing the web properly -though it's not strictly necessary to use provider-specific DNS. This means that you can use other DNS for your internet connection; sometimes even improving the browsing speed since high-quality DNS are capable of quickly resolving new domain names.

There's more than meets the eye when performing an ADSL speed test. Whenever you measure your DSL or ADSL broadband speed, you have to take into consideration that packets travel through broad band.
The test must also take into consideration the technology used to deliver these packets and the variants that may fluctuate in your ADSL speed. To get results as accurate as possible, our internet test was developed with the most sophisticated speed test techniques by using servers spread throughout the world so that the speed test could be as consistent as possible when users surf the web.
When it comes to preparing our speed test, since the test design must be clear and user-friendly, we also need to consider the presentation and accuracy of the results provided.

To perform an ADSL upload test, we use a default amount of UDP packets of uniform size at a rate slightly higher than the nominal tested ADSL. In order to perform a test with a slightly higher rate than the one that is recommended by the default, it is necessary to saturate the broadband test.
The processes in our servers dedicated to test ADLS speed, return an echo of the packets sent as they reach the server. The time difference, T, is measured between the arrival from the first to the last packet the user receives.

A server traffic generator is reserved for the speed test, generating download traffic for ADSL users. It is a process specifically designed to receive that kind of information, measuring the arrival time of packets. Given the nature of ADSL connection (where download speed is much greater than upload) the client cannot create an echo of the packets sent. In this case it is used the same user PC to measure the download speed of the ADSL user.