[ntp:questions] NTP vs chrony comparison (Was: oscillations in ntp clock synchronization)
mayer at ntp.isc.org
Tue Jan 22 03:36:29 UTC 2008
>> correction applied on that sample.
> No, this is offset as measured by the ntp procedure ( (t1+t4-t2-t3)/2 )
No, that's wrong. It is very carefully described in the NTPv4 draft
section 8 (p27):
theta = T(B) - T(A) = 1/2 * [(T2-T1) + (T3-T4)]
Not only do you have the wrong sign, the differences must be calculated
first, otherwise the errors in the calculation overwhelm the resulting
value. That's why it's written the way it is.
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