[ntp:questions] Is this normal?
David.Russell at dowjones.com
Mon May 10 17:45:05 UTC 2010
I am trying to verify the correct implementation of NTP on a device that is configured to poll a GPS based dedicated time server on the local area network. The round trip times to this stratum 1 vary between 3.3 and 3.4ms.
I have plotted the offset vs drift in the included jpg. The drift rate varies between -3 and -3.2 us/s and the offset is +/- 200us. Note that the first part of the graph is when NTP started.
My questions are that given that a device has excellent network access to a good stratum 1 server should the drift rate vary this much? Can I infer anything from the data regarding proper computations in the code, timestamping of the packets or even the system clock?
Thanks in advance,
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