[ntp:questions] Re: Reading time offset from ntp variables using ntpq

Daniel Kabs daniel.kabs at gmx.de
Wed Feb 22 07:47:28 UTC 2006


Hello David!

David Woolley wrote:
>>Originate: the time the request packet left your system
>>Receive: the time the request packet arrived at the server
>>Transmit: the time the reply packet departed the server
> 
> The measurement takes a finite time to make (delay I think, but it might
> be twice delay).  Basically it takes between Originate and Originate + delay
> (the client receive time isn't recorded here).  Therefore you cannot state
> one specific time at which the measurement was made.  Using any of the
> latter 3 should be OK as long as you always use the same one.  Note that,
> as the clock isn't being disciplined, Originate may differ drastically 
> from Receive and Transmit (i.e. by offset).

Thank you for clarifying the meanings and usage of the timestamps. I'll 
try to include the explanations which everybody contributed to this 
thread on
https://ntp.isc.org/bin/view/Support/HowToCalibrateSystemClockUsingNTP


> ... Nowadays, I use ntptime, to set the kernel parameters,
 > and don't run ntpd at all....

Using "ntptime" is a great suggestion. I planned to use "adjtimex" for 
this job but it's more than twice the size of "ntptime". So I'd rather 
use the latter one to save some kBytes :-)

Cheers
Daniel
-- 
Refactor, don't archive! - SamHasler - 28 Aug 2004 - twiki.org




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