On 2008-08-13, John Bartas <[EMAIL PROTECTED]> wrote:
> Hi Folks,
>
> I have some questions about when (if ever) NTP will set time backward. 
> I'll be using it on Embedded Linux for time stamping video frames.
>
> I've found several mentions in RFC 1305 that this should not happen, and 
> also in section "Step Phase Adjustments" mention that it can jump 
> backwards.

ntpd has a default step threshold of 128ms. When the offset does not
exceed this threshold the clock is slewed. When the offset exceeds this
threshold the clock is stepped.

> Is there a simple description anywhere if what variables affect this, 
> and how? I'd like to know when it's going to jump backwards on Linux - 
> what the rules are and what control I have over it.

The ntpd manual page,
http://www.eecis.udel.edu/~mills/ntp/html/ntpd.html (dev release)
or http://doc.ntp.org/4.2.4/ntpd.html (stable release), provides a
description of now NTP works. Start at the "How NTP Operates" section.

-- 
Steve Kostecke <[EMAIL PROTECTED]>
NTP Public Services Project - http://support.ntp.org/

_______________________________________________
questions mailing list
[email protected]
https://lists.ntp.org/mailman/listinfo/questions

Reply via email to