Re: [Ntp] Local time in NTPv5?

9

On Sat, Jul 30, 2022, 8:56 PM Danny Mayer <mayer@pdmconsulting.net> wrote:

>
> On 7/27/22 11:01 AM, Miroslav Lichvar wrote:
> > There are some very simple devices like clocks or security cameras
> > that use NTP for synchronization, but they need to know the time zone
> > in order to display local time. Selecting the time zone and/or
> > updating the data may be difficult. I have heard of some cases where
> > people gave up on the configuration and instead patched their NTP
> > server to compensate for the offset between the default time zone and
> > local time.
> >
> > I'm wondering if NTPv5 could better support this use case. In my draft
> > there already is UTC, TAI, UT1, and leap-smeared UTC. Local time could
> > be the 5th timescale to be requested by the client. The timescale
> > offset field could be the offset to UTC in minutes (in seconds it
> > would not fit the 16-bit field for some zones).
> >
> > The assumption is that the client doesn't know where it is, but it
> > expects the server (e.g. from the DHCP NTP option) to be in the same
> > time zone. The software would be simplified and no time-specific
> > configuration is required.
> >
> > Does that seem reasonable?
> >
> This makes no sense at all. NTP only knows about UTC. All major
> operating systems store timestamps in UTC. Time-zones are just a display
> issue. The software displaying the timestamps is responsible for
> displaying timestamps in the appropriate way. You are incorrect in
> stating that no time-specific confguration is required. NTP doesn't know
> where a client is nor does it have any way of telling. The client does
> know. Don't expect NTP to deal with the Olson time-zone database.
>

I work for a video streaming company. I'm in mountain time, but others are
in a dozen timezones. Sometimes when I deal with one our servers scattered
all over the world I care about local time (mine) other time I care about
the time of the majority of its streamers. Other times I care about local
time of the Colo it is at. Now multiply it by those dozens of colleagues.
There is no local time once you get away from one's self.

This is a long way to say I agree and it's not a good fit for ntp's remit.
The tz database really only shares a name with NTP. But it the domains
don't really overlap.

Warner

Danny
>
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