[ntp:questions] Magice Server Numbers: 4,5,7,9

David L. Mills mills at udel.edu
Fri Sep 16 14:06:58 UTC 2011


We would not be having this discussion if folks read "how NTP works" in 
the online documentation, in particular, the page on the select 
algorithm. The number of candidates is not limited to ten. By default, 
ten is the high water mark for survivors mobilized as preemptible in 
manycast and pool modes.


Danny Mayer wrote:

>On 9/16/2011 2:24 AM, unruh wrote:
6. Seven clocks allow for the failure of three.

>>>Etc, etc. . . .
>>The only answer is to have at least 10000000000001 clocks although that
>>is also not foolproof:-) 
>Actually no. If you get too many reference clocks they will start to
>gang up against each other and it becomes impossibly complex to try and
>decide which set to use. As the number of clocks increase the number of
>gangs will likely increase. That's why the reference implementation
>limits the number of reference clocks to 10.
>questions mailing list
>questions at lists.ntp.org

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