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Add an NTP Source

TimeKeeper supports nearly any form of NTP, and can achieve sub-microsecond accuracy with the protocol if the NTP implementation is adequate.

Typically, TimeKeeper running on VelaSync will be deployed as an NTP server, offering the following features:

  • Accuracy in the low hundreds of nanoseconds
  • Management capabilities to record the reported accuracy of NTP clients
  • Support tens of thousands of clients per second from a single instance.

To change the configuration of an existing NTP source, or create a new NTP source:

  • Navigate to Configuration > TimeKeeper configuration, and under the Sources tab, select the NTP source you would like to edit, or select Add a new source below.

Editing/Adding an NTP Source

The editable features are:

NTP server

The IP address or DNS name of the intended NTP server.

NTP sync rate

Rate at which to query the server, in packets/sec. A value of 0.9 would query every 1.1 seconds. A value of 0.5 stands for a query every 2 seconds. See also NTP Query Rate.

Sync error threshold

If the sync quality (offset) exceeds this floating point value, emit trap/syslog messages.

Major time

[Choose one: SOURCE0, 1, 2, etc.] Combine this source's second-scale time with time of day information from the source named here. [Default: unselect/Choose one]

Cable delay

Bias the clock to account for cable delays or asymmetries. With a long cable run that delays signal by 1ms, use a value of 0.001. TimeKeeper will subtract this value from the incoming timing signal.

Designate a low quality source

Assume source is very low quality and prioritize minimal changes to local oscillator to stabilize time.

Periodically re-resolve DNS name

If enabled, will cause the source to periodically re-resolve the DNS name specified for the NTP source.

Detect asymmetry

Enable to detect and measure network link asymmetry. Your network needs to be properly configured to test for asymmetries. For more information, see Detecting Network Asymmetries.


Note: Do not forget to click Save TimeKeeper changes in the upper right corner, once you have applied your changes.

Additional information about adding sources can be found under Configuring Timing Sources.