[ntp:questions] NTP and SNTP in the end, give me precision of 1ms?

Unruh unruh-spam at physics.ubc.ca
Sun Sep 14 03:33:47 UTC 2008


David Woolley <david at ex.djwhome.demon.co.uk.invalid> writes:

>Unruh wrote:

>> 
>> An SNTP canot be a server if it is not tied to a hardware clock.

>s/cannot/should not/  Pre-Windows 2003 versions of w32time are examples 
>of some things that are commonly used in violation of the rule.

I should have said, and SNTP which complies with the RFC specification....


>Generally, though, Unruh is on the right lines; whilst you can make some 
>assumptions about the abilities of an NTP client, you can make none 
>about those of an SNTP one, as the specification says nothing about how 
>it uses the measurements it makes.  (NTP is still at the mercy of 
>unusual configurations and hardware, software and networking issues.)

>SNTP clients are often used with very long poll intervals, that are not 
>compatible with 1ms tracking.




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