[ntp:questions] 500ppm - is it too small?

Richard B. Gilbert rgilbert88 at comcast.net
Mon Aug 17 18:24:29 UTC 2009


nemo_outis wrote:
> "Richard B. Gilbert" <rgilbert88 at comcast.net> wrote in
> news:poydnd1spod4pBTXnZ2dnUVZ_vudnZ2d at giganews.com: 
> 
>> I still haven't seen any argument that supporting a value greater than
>> 500 PPM is worth the trouble!
> 
> I still haven't seen any evidence that there is much trouble - only 
> anticipatory speculative whinging. 
> 
> Nor, for that matter, has there been much other than speculation and vague 
> anecdotal recollections that the 500 ppm limit *may* have had some 
> justification and not been entirely arbitrary.
> 
> This doesn't inspire much confdence about the documentation of the 
> architecture and design decisions regarding ntp.
> 
> Regards,
> 
> 

I think "Das Buch" a/k/a  "Computer Network Time Synchronization: The 
Network Time Protocol" by David L. Mills might help you understand the 
design and how it was derived.

See:
http://www.amazon.com/s/ref=nb_ss?url=search-alias%3Daps&field-keywords=NTP&x=0&y=0

I think you will need some background in "control systems", "phase 
locked loops" and other such esoterica.  I don't pretend to understand 
the math.  I simply use the software derived from it to synchronize my 
clocks.

NTPD does that nicely!




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