IRITI puts at everybody disposal on the Internet network the
following time services, synchronized directly with the source of the italian standard time: the right time and the NTP primary
To be kept updated about these services, one can subscribe to the mailing list time sending a mail to the address email@example.com with the word subscribe in the field Subject.
To have more information send a mail to firstname.lastname@example.org .
It is a www page containing the date and the hour at the time of page transmission.
The page reception has variable delays generally greater that 1 second, mainly produced by the transmission performance of the Internet network through all the way from the right time server to the requesting computer.
After the first reading, the page can be manually updated using the reload command available in every www browser.
Pay attention to the cache option of www browsers: it can give rise to readings of old pages of right time. In doubt, give at least one reload command.
The figure shows an example of right time page with an explanation of the less evident elements.
Since 1993 February, a NTP primary server synchronized by a direct link to the italian standard time of the National Electrotecnical Institute "G. Ferraris" is active at IRITI. The server and the time source are in the same building.
The following table shows the characteristics of the NTP primary.
|NTP software||ntp 4.0.99k|
|reference clock||IEN CTD directly connected|
|maximum deviation from reference||10 ms|
|access policy||open to everybody (1)|
|geographical position||45°00'54"N, 7°38'20.7"E, 306.6H|
|site, locality||IRITI, Torino - Italy|
To have more detailed information about working principles, installation and usage of NTP software, read the Network Time Protocol (NTP) page.
who is already
List of computers (NTP clients) already synchronized on the primary server, updated at every midnight. The list includes al NTP clients that synchronized at least one time since the last reset of the NTP software on the primary server.
accuracy of synchronization
The accuracy of the synchronization was measured as the dispersion and the offset from the primary server. The values range from minimums of few milliseconds for computers on the same local network of the server, to maximums of hundreds of milliseconds for computers connected to remote networks.
The following table shows the accuracy values measured on 1996 January on some computers continuously synchronized to the primary server. The hop distance shows the number of Internet nodes (typically routers) between client and sever. The table is ordered by ascending number of hops. All times are in milliseconds.
|client site||hop distance||time distance||offset||dispersion|
F. Pollastri - The Time of Internet