NTP statistics

This page is related to the Control Center interface.

Description

Network → NTP

Date/Time → NTP Statistics

The following NTP information is displayed within the Control Center interface:

• Server IP.
• Stratum

  A static measure representing the number of servers up to a reference time-server (usually an atomic clock).

• Status:
  • peer - this is the server used for the time synchronization;
  • candidate - this is a server whose time is consistent with the player and may be used in case the peer is no longer available;
  • reject - the server is not used, because its stratum is too low, or it has been configured as "Monitor only" in the Time Sources;
  • oulier - the server is too different from the peer to be used for synchronization;
  • initializing - during transition phase or when it cannot be reached;
  • unreachable - the server cannot be reached.
• Reach

  How often the server has been reached as a percentage within the last 8 attempts; it should be as close as possible to 100%.

• Time offset

  The time difference in milliseconds between the player's time and the NTP server's time.

• Delay

  The time delay in milliseconds between the moment the player has sent the request and got the answer from the NTP server; it should be as small as possible.

• Dispersion

  When repeatedly reading the time, the time offset may vary almost randomly, and the difference (second derivation) of these time offsets is called jitter or dispersion. Note that a small value is needed for synchronized content.

• Poll interval

  The time interval between requests towards the NTP server. It will start with the minimum value and gradually increase up to the maximum value; for internal NTP servers (min, max) = (16s, 256s) and for public ones (min, max) = (64s, 1024s).

After the NTP statistics, the information regarding the local clock calibration is displayed. The correction is displayed in ppm (part per million); for instance, 1ppm would mean that the internal clock will drift with 32 seconds in a year.

Troubleshooting

• In case some of your NTP server can't be reached ("Status" column always remains "Initializing"), it may be behind a firewall or just wrongly configured. Check the NTP server configuration with your system administrator.
• The values in the column "Time offset" should be as close to 0 as possible, it this is not the case, then it might be necessary to either check the network configuration or change the NTP server.
• The NTP server might be rejected if the dispersion value is high, at least higher than the time offset.