[ntp:hackers] Further to the timestamping issue

Poul-Henning Kamp phk at phk.freebsd.dk
Mon Jun 16 12:16:48 UTC 2008

In message <4855E47F.2030203 at udel.edu>, "David L. Mills" writes:

>> * Change/Define Root Dispersion to be useful/meaningful
>> While statistically correct, the number is of no use and often
>> deeply misleading.
>I submit the current semantics are correct, although maybe not 
>as clear in the documentation. If you found this confusing, you should 
>have spoken up before.

I did not say they were not correct, I said they were of no use.

And as a result of that, they are more likely than not to be
correct on the wild network since people don't bother setting
them right for their stratum 1 servers.

Some of this originates with the software, for instance most DCF77
refclocks do not use the same definition of root delay as your
quoted for WWVB.

>> * Fix leapsecond handling.
>> Add timestamp of next scheduled leapsecond, so that clients can
>> handle the event correctly, even if they are offline at the time.
>You need to be more explicit about "fix leapsecond handlin"g.

The current leapsecond handling gives a very short warning about
an impending leapsecond, despite the fact that we know six months
in advance that it will happen.

A device which is "off the net" during the short interval around
the leapsecond, will not know to do the right thing.

This is a particular problem with DCF77 stratum1 servers which 
only get 1 hour leap-second warning in PTB's transmissions.

We should add a field that can contain the time of the next
scheduled leapsecond:

	"Next leapsecond is at [32bit seconds]"

So we can set it at the time when we receive The Bulletin from Mr.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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