Mobatime DTS 4801.masterclock, Инструкция по эксплуатации

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8.2 Time take-over, NTP
Generally NTP as per RFC 1305.
Maximum 4 sources.
Reference clock for DCF with selectable time zone.
Time take-over from DCF:

Reference clock for the reception from DCF.
At least 3 minutes of reception required before the NTP server is available.
Stratum of the time source = 0

Stratum of DTS 480x = 1.
Time take-over from NTP:

As per NTP RFC 1305 (www.ntp.org)
(see http://support.ntp.org/bin/view/Servers/WebHome for servers on internet)
Time take-over from RTC (internal time of the DTS 480x):

The NTP server is started with stratum 3, if a DCF source is configured.
As soon as a time source delivers the time, the stratum is set accordingly.
If there is no DCF time source configured, the NTP server will only start when it
receives the time from another NTP server.
Manual time setting:

The NTP server will be started with stratum 3 if DCF is configured as time source.
As soon as a time source delivers the time, the stratum is set accordingly.
If there is no DCF time source configured, the NTP server will only start when it
receives the time from another NTP server.
Error cases:

DCF failure:
Depending on the setting of the “Stratum TO (1-16)”, the stratum will be counted
upwards, till it reaches 16.
When the startum reaches the value "Stratum limit for synchalarm", the alarm
"Failure time source Str" occures (fix delay of 1 min) and the sync LED turns off.
When a time source is available again, the stratum will immediately be set according
to the time source (stratum time 1).

DCF failure with NTP as backup time source:
Depending on the setting of the “Stratum TO”, the stratum will be counted upwards,
till it reaches 16.
In case the stratum limit is reached and a NTP server with a better stratum is
available, the DTS 480x synchronizes from NTP.
When the local time source is available again, the stratum will immediately be set
according the time source (stratum time 1).

NTP failure:
The failure of the/all NTP source/s without a defined fix stratum and without DCF.
Normally, it takes 8 * the poll intervall of the current source until the peer is
recognized as invalid (source can no longer be reached) and NTP loses
synchronization. The length of time, with the exception of the poll interval, also
depends on the jitter measured, number of sources, length of synchronization and
source deviation, and can thus deviate enormously in individual cases.
Exception for time take-over:
After a software update, the first time take over can last distinctly longer (> 8
minutes).