[ntp:questions] Advice for a (LAN-interconnected) WLAN Testbed w/ ARM nodes

David L. Mills mills at udel.edu
Wed Aug 4 02:31:22 UTC 2010


Guys,

May I suggest you review the definitions of system offset (THETA), root 
distance (LAMBDA) and system jitter (PSI) in Section 11.2 of rfc5905.

Dave

David Woolley wrote:

> Miroslav Lichvar wrote:
>
>> But there will be more clock updates. Noise in frequency may go up,
>> but the offset will be the same or better, unless there are network
>> congestions that last longer than the clock filter can handle (8 *
>> poll interval).
>>
> The "offset" may be better, but offset is not the offset from true 
> time, it is the offset from the sum of the upstream server time and 
> the measurement errors for the last poll.  There should be no way of 
> measuring the error from UTC.  The fact that you can do so, to some 
> extent, is due to the NTP algorithms being less than ideal.
>
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