[ntp:questions] Re: ntpd -x

Brian T. Brunner brian.t.brunner at gai-tronics.com
Mon Jan 30 15:37:17 UTC 2006

>>> "David L. Mills" <mills at udel.edu> 01/27/06 12:09PM >>>

DaveM> At the very real risk of boring everybody on this list to tears, I have 
DaveM> a burning agenda to expose this issue to a responsible community.

DaveM> Your flight dispatcher machines are running just fine and one of them 
DaveM> suddenly veers off course by one hour. Your application is air traffic 
DaveM> control. Your choices are:

This seems to cross the boundary between NTP and the application.
NTP has no way of telling whether all the machines running a particular 
distributed application all have the same notion of "the time".

A significant question is whether the distributed database application  
(air traffic control in this case) runs on machines that all are NTP co-peers 
or co-clients of a single time server (set)?

AIUI, NTP only disciplines the local clock, and passes judgement on the credibility
of other clocks; it does not judge itself to be the false ticker, so it can't tell
the application that the time returned (on this machine) is hysterical, and the 
application should go ask someone else.

I think it is outside NTP's current scope to implement NDC (Network Distributed Clock)
or NTOD (Networked Time Of Day)  or NTR (Network Time Reference) to  provide 
"the time" for all distributed application actions.  Are you (David) suggesting that
the NTP project scope be broadened to embrace some concept of NTOD?

Brian Brunner
brian.t.brunner at gai-tronics.com

This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.

This footnote also confirms that this email message has been swept
for the presence of computer viruses.

www.hubbell.com - Hubbell Incorporated

More information about the questions mailing list