[ntp:questions] Re: ntpd transmit timestamp precision

Richard B. Gilbert rgilbert88 at comcast.net
Sun Feb 19 22:30:34 UTC 2006


David L. Mills wrote:
> Harlan,
> 
> I'm uneasy calling random() for every read of the clock, as it could be 
> expensive. It seems a bit overkill to fuzz the nanobits when the caller 
> has timespec and fuzzed to 10 ms. Perhaps a test of precision greater 
> than a microsecond is advised.
> 
> Dave

Why is this important for nptd to do?  RFC 2030 calls for it in SNTP 
implementations but doesn't ntpd have other means for detecting loops 
and replays?  Don't a LAN and/or a WAN introduce enough jitter to make 
the low order bits meaningless in any case?




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