With the Network Diagnostic Tool (NDT), the user measures the performance of his/her connection and, more specifically, receives statistical data relating to its most important quality features: speed (throughput), Round Trip Time (RTT), jitter and packet loss rate.
When conducting a measurement, the user’s computer communicates with a specially designed server having a high capacity connection and located at a central point of the network. By analyzing the communication between the server and the user’s computer, the afore-mentioned parameters are calculated and presented to the user.
The duration of a measurement does not exceed 30 seconds. For using NDT, a modern browser is required that supports HTML5 and the WebSocket protocol.
In the measurement page of NDT, users are asked to agree to the data policy before running a measurement. Then, by pressing the BEGIN button, the user executes a default set of measurements. At the start of the measurement, a set of controls are performed (firewall test, test for duplex mismatch detection, etc.). Measurements are done separately in the uplink and downlink directions; a typical measurement lasts 10 seconds in each direction. After the measurement is completed, the basic results are shown on screen: test server location, download and upload speed, latency (RTT), retransmission rate (packet loss rate) and jitter.
After completion of a measurement, the user can see a more detailed report of the measurements, by clicking on DETAILS. The report includes values of TCP parameters (receive window, number of duplicate ACKs, RTO, etc.) as well as useful diagnostics, for which detailed information can be found in the relevant Mesurement Lab web page
The system includes several controls in order to avoid recording measurements with non-verified user data. For example, it does not record measurements performed from mobile networks, from networks of fixed providers who have not registered their IP ranges with EETT, or from networks outside Greece.
If a registered user tries to make a measurement from a non-identified IP address, the following message will appear:
Υour IP address [x.x.x.x] is not registered by your ISP in the HYPERION database. Your measurement results shall not be stored. In case you are a subscriber of a Greek ISP, please report the problem to your ISP or to EETT.
In this case, if a user makes this measurement from a fixed connection, the correspondent ISP should inform EETT about the IP ranges used by its customers, and the offered nominal speeds. Measurements would subsequently be stored. However, if the user makes this measurement from a mobile connection, it would not be stored.
In the case of users outside Greece attempting to register, the following error message appears:
Υour IP address is not registered by your ISP in the HYPERION database. Unfortunately you cannot register, but you can still perform measurements anonymously. In case you are a subscriber of a Greek ISP, please report the problem to your ISP or to EETT.
Furthermore, before each measurement by a registered user, a check is performed on whether the user’s IP address corresponds to the ISP stated in the user’s account. If there is no agreement, the following error message appears:
It seems that your current IP address belongs to an ISP different from the one of your selected connection. If you wish to register your measurements, select the correct connection from the list or set the correct ISP in the Settings of this connection.
Usually, this problem appears when a user has created different connections (e.g. home, office) and does not choose the correct one before running a measurement. Additionally, when users have changed ISP and have not updated their account information. To solve these problems, users just have to choose the correct connection, or update their account information prior to the measurement.