[ntp:questions] LOCL clock reachability not 377?

Harlan Stenn stenn at ntp.org
Wed Jul 30 22:15:30 UTC 2014

David Woolley writes:
> On 30/07/14 07:50, mike cook wrote:
> > Paradoxically , the LCL clock is fine when there are no refclocks.
> > That is, when you don't need or want it.
> My understanding was that the original purpose of the local clock was
> to cover the case when there were no NTP managed reference clocks (but
> there was another reference clock disciplining the machine with UTC).
> That's why the default stratum is in the mid-range, rather than the
> high numbers.

The "Undisicplined Local Refclock" driver was originally designed to
solve the problem where a group of machines would all take their own
paths off into the weeds if nobody had a connection to a real clock.

For this general case, orphan mode is now the recommended solution.

Later it was discovered that folks like NIST could use the local
refclock with the LOCKCLOCK code, as they had other software that
controleld the system clock and therefore the local refclock was usable
as a time source.

The reason to use a "middle range" stratum for a local refclock is so
that nobody else will start to belive that source if that machine gets
access to outside machines again.

See http://support.ntp.org/bin/view/Support/UndisciplinedLocalClock for
more information about the stratum configuation, in the "Dual Time
Servers" section.
Harlan Stenn <stenn at ntp.org>
http://networktimefoundation.org - be a member!

More information about the questions mailing list