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8.4
Time acceptance from NTP
Acceptance:
•
As NTP RFC 1305, RFC 5905 (www.ntp.org)
(see http://ntp.isc.org/bin/view/Servers/WebHome for internet-server)
Stratum in normal, synchronized operation:
•
Stratum value of DTS is always one step higher than that of the current NTP time
server
Stratum in case of an error
•
As NTP RFC 1305, RFC 5905 (www.ntp.org)
8.5
NTP as backup
If DTS 4132 is synchronized with a DCF or GPS source, the NTP can be used as
redundancy source. This function is active, as soon as at least one time server is
configured in menu ‘2. Configuration’
‘2. Time handling
‘4. NTP server’).
Stratum in normal, synchronized operation:
•
Equal Stratum value “Time Acceptance from an external source (DCF or GPS)”
Behavior in case of an error:
•
Failure of primary Source:
"St. est": Means: Expected NTP Stratum of the NTP sources
"St. est" = MAX(Stratum NTP candidates)
Means: "St. est" contains the stratum value of the poorest NTP source.
If internal Stratum > "St. est" + 1, then change to NTP as source takes place
(internal stratum is one step higher than that of the poorest available NTP source).
•
As soon as the primary source is available again, the changes are set back.
8.6
Time server
•
NTP v4 (compatible with v3) as per RFC 1305, RFC 5905 (Port 123)
•
SNTP (UDP), RFC 2030 (Port 123)
•
TIME (TCP/UDP), RFC 868 (Port 37)
•
DAYTIME (TCP/UDP), RFC 867 (Port 13)
8.7
Time accuracy, time-keeping
See appendix H Technical data.