[ntp:hackers] Server timestamps going backwards by up to 2 milliseconds

David J Taylor david-taylor at blueyonder.co.uk
Wed Dec 23 10:04:53 UTC 2009


David,

On low precision systems, the effect of adding the "fuzz" in the low-order 
bits of the timestamps can result in timestamps in the NTP packet returned 
from the server going backwards by as much as two milliseconds (measured). 
The transmit timestamp from the server can indicate a time earlier than 
the receive timestamp.  Is this really desirable?  What effect might it 
have on NTP clients which use such servers?

If there is a need for the "fuzz", should just the receive timestamp be 
fuzzed, and the transmit reported as "fuzzed receive + epsilon", so that a 
forward progression of time is maintained?

Thanks,
David
-- 
SatSignal software - quality software written to your requirements
Web:  www.satsignal.eu
Email:  davidtaylor at writeme.com 




More information about the hackers mailing list