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E-MAIL: OFFICE@VNIIFTRI.RU

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15.06.2019

 

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SERVICES OF NTP SERVERS

FSUE VNIIFTRI provides open access to timeline synchronization servers using the NTP protocol. Currently, there is a grouping of 4 stratum 1 servers connected to the state primary standard of RF time, 4 stratum1 servers connected to secondary standards and one stratum 2 server synchronizing with the main grouping of servers. All servers provide access via the NTPv4 IPv4 protocol in accordance with the international standard RFC-5905.

The NTPv4 protocol provides synchronization accuracy of the order of tens of milliseconds when interacting over the Internet.

Support for this protocol is implemented for most operating systems:

  • ntpd daemon for Unix-like systems;
  • built-in date and time settings or W32tm.exe for MS Windows operating systems.
Address Port Level Device Access
ntp1.vniiftri.ru IPv4 UDP 123 stratum 1 Meinberg LANTIME M300/MRS свободный
ntp2.vniiftri.ru IPv4 UDP 123 stratum 1 Meinberg LANTIME M300/MRS свободный
ntp3.vniiftri.ru IPv4 UDP 123 stratum 1 Meinberg LANTIME M300/MRS свободный
ntp4.vniiftri.ru IPv4 UDP 123 stratum 1 Symmetricom SyncServer S250i свободный
ntp21.vniiftri.ru IPv4 UDP 123 stratum 2 Linux kernel ntpd 4.2.6 Intel Xeon свободный

ntp1.niiftri.irkutsk.ru IPv4 UDP 123 stratum 1   свободный
ntp2.niiftri.irkutsk.ru IPv4 UDP 123 stratum 1   свободный

vniiftri.khv.ru IPv4 UDP 123 stratum 1  Meinberg LANTIME M300/MRS свободный
vniiftri2.khv.ru IPv4 UDP 123 stratum 1  Meinberg LANTIME M300/MRS свободный

NTP uses UDP for its work. The NTP system is extremely resistant to changes in media latency.

NTP uses the Marzullo algorithm (proposed by Keith Marzullo from the University of California, San Diego), including such a feature as transmission time accounting. In version 4, it is able to achieve an accuracy of 10 ms (1/100 s) when working via the Internet, and up to 0.2 ms (1/5000 s) and better within local networks.

The time is represented in the NTP system by a 64-bit number (8 bytes) consisting of a 32-bit counter of seconds and a 32-bit counter of fractions of a second, allowing you to transfer time in the range of 232 seconds with a theoretical accuracy of 2−32 seconds. Since the time scale in NTP is repeated every 232 seconds (136 years), the recipient must at least know approximately the current time (with an accuracy of 50 years).