David L. Mills wrote:
> David,
>
> In the NTPv3 spec the leap bits are to be set on the day of the leap.
> This is compliant with the new NTPv4 spec; that spec is more liberal
> in order to support and prioritize leap warnings when multiple means
> are available. In cases where the radio delivers a timecode via
> serial port, some radios include provisions for leap warning; some do
> not. I don't know if an NMEA sentence has provisions for that. There
> are no provisions for leap warning in IRIG devices I have.
>
> I  don't know if the Meinberg GPS or EndRun CDMA receiver include
> provisions for leap warning. If so, it should appear in the NTP header
> on the day of the leap. Both receivers use an embedded Linux system
> which in principle has the same provisions as the public
> distribution..
>
> Dave

Thanks, Dave.  I don't know about the NMEA sentence either, but I don't 
recall seeing that possibility.  On my GPS-based server, it does also have 
Internet sources, but even though one of those sources is showing the leap 
bit, my server is not.  I'll have to check on December 31st.  It will be 
disappinting if I have similar problems to last time!

  http://www.satsignal.eu/ntp/ntp-events.htm#leapsecond

In view of the popularity of the GPS18-LVC it's a pity that the driver 
support for the leap second isn't better, but I appreciate that being able 
to test once every few years doesn't make things any easier!

Here are the results from my own server, and two of the five Internet 
servers to which it is connected.  Disappointingly, the three pool servers 
didn't respond to the "ntpq -c rv" command.  Of the other two, one 
indicates a leap second, and the other doesn't.

__________________________________________________________
C:\>ntpq -c rv pixie
assID=0 status=2484 leap_none, sync_uhf_clock/PPS, 8 events, 
event_peer/strat_ch
g,
version="ntpd 4.2.0-a Sun May  8 06:01:21 UTC 2005 (1)",
processor="i386", system="FreeBSD/5.4-RELEASE", leap=00, stratum=1,
precision=-17, rootdelay=0.000, rootdispersion=2.125, peer=5113,
refid=PPS, reftime=ccf1ca39.2c218fe1  Tue, Dec 16 2008  6:33:29.172,
poll=6, clock=ccf1ca43.fbb22262  Tue, Dec 16 2008  6:33:39.983, state=4,
offset=0.008, frequency=41.314, jitter=0.005, stability=0.018

C:\>ntpq -n -p pixie
     remote           refid      st t when poll reach   delay   offset 
jitter
==============================================================================
+78.129.142.80   195.66.241.3     2 u   46   64  377   22.441    2.319 
0.441
+212.13.194.96   212.13.204.4     3 u   28   64  377   20.532    1.125 
1.354
+213.130.44.252  128.250.33.242   2 u   37   64  377   22.043    1.964 
0.322
-88.96.233.89    192.53.103.108   2 u   54   64  377   64.083    3.175 
0.593
-130.88.200.6    193.62.22.98     2 u    3   64  377   26.839   10.450 
0.467
*127.127.20.1    .PPS.            0 l   14   64  377    0.000    0.008 
0.008

C:\>ntpq -c rv 78.129.142.80
78.129.142.80: timed out, nothing received
***Request timed out

C:\>ntpq -c rv 212.13.194.96
212.13.194.96: timed out, nothing received
***Request timed out

C:\>ntpq -c rv 213.130.44.252
213.130.44.252: timed out, nothing received
***Request timed out

C:\>ntpq -c rv 88.96.233.89
assID=0 status=06f4 leap_none, sync_ntp, 15 events, event_peer/strat_chg,
version="ntpd [email protected] Tue Nov  4 15:54:13 UTC 2008 (1)",
processor="i386", system="FreeBSD/7.1-PRERELEASE", leap=00, stratum=2,
precision=-21, rootdelay=83.613, rootdispersion=24.271, peer=30612,
refid=192.53.103.108,
reftime=ccf1c8ec.39dc931f  Tue, Dec 16 2008  6:27:56.226, poll=10,
clock=ccf1cac8.5e837314  Tue, Dec 16 2008  6:35:52.369, state=4,
offset=0.174, frequency=-66.147, jitter=0.438, noise=0.392,
stability=0.020, tai=0,
access_policy="experimental server not suitable for production use"

C:\>ntpq -c rv 130.88.200.6
assID=0 status=46f4 leap_add_sec, sync_ntp, 15 events, 
event_peer/strat_chg,
version="ntpd 4.2.0-a Wed Jul 23 12:48:29 BST 2008 (1)",
processor="i386", system="FreeBSD/6.3-STABLE", leap=01, stratum=2,
precision=-17, rootdelay=1.723, rootdispersion=54.425, peer=38190,
refid=193.62.22.98,
reftime=ccf1ca10.7782ce5d  Tue, Dec 16 2008  6:32:48.466, poll=10,
clock=ccf1cade.07d6bcb6  Tue, Dec 16 2008  6:36:14.030, state=4,
offset=-10.270, frequency=-0.505, jitter=9.321, stability=0.004
__________________________________________________________ 

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