[ntp:questions] different Ntp servers...

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Tue May 26 12:56:32 UTC 2009

Andy wrote:
> About 10 years ago we used to have 2 seperate GPS receivers feeding
> into two Sparc servers via their serial port. I can't remember the
> version of NTP we ran however these were our stratum one servers, One
> of the Sparcs developed a fault on it's serial interface which delayed
> the input meaning the two stratum one servers started showing
> different time so all the statum 2 servers stopped trusting both
> stratum 1 servers as they could not determine which server, if any,
> was telling the  truth. Ever since then we have always used at least 3
> stratum one servers with seperate stratum zero sources to form a
> quorum so that startum 2 can differentiate the good from the bad. I
> believe this is set down as best practise in the ntp.org FAQ - this is
> a practical example of why this is wise.

The "best practice" is in fact to use at least _four_ sources, that way 
you can lose one and still have a voting group.


- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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