[ntp:questions] NTP.ORG MEINBERG KEEP TIME ACCURATE to 10MS

David Lord snews at lordynet.org
Thu Nov 15 09:06:21 UTC 2012


Richard B. Gilbert wrote:
> On 11/14/2012 12:02 AM, E-Mail Sent to this address will be added to the 
> BlackLists wrote:
>> gbusenberg at yahoo.com wrote:
>>> I am now left with two lines in ntp.conf
>>> driftfile "C:\Program Files\NTP\etc\ntp.drift"
>>> server 10.1.126.204 iburst minpoll 5
>>
>> There have been plenty of improvemnets since 4.2.6p5 circa 2011Dec24
>> <http://www.davehart.net/ntp/win/x86/ntp-4.2.7p310-win-x86-debug-bin.zip>
>> <http://www.davehart.net/ntp/win/x86/ntp-4.2.7p310-win-x86-debug-sym.zip>
>>
>> # ALL (Clients and/or Servers)
>> #  Start the Service with C:\Program Files\NTP\bin\ntpd.exe -U 3 -M -g 
>> -c "C:\Program Files\NTP\etc\ntp.conf"
>> #   the -g will prevent a panic stop if the time needs to be steped 
>> when started
>>
>> # ntp.conf
>> driftfile "C:\Program Files\NTP\etc\ntp.drift"
>> statsdir "C:\Program Files\NTP\etc\"
>> enable monitor
>> enable stats
>> statistics loopstats peerstats
>> keys "C:\Program Files\NTP\etc\ntp.keys" # e.g. contains: 123 M 
>> YOUR_MD5_KEY
>> trustedkey 123
>> tos cohort 1 orphan 11
>> restrict default limited kod nomodify notrap
>> restrict 127.0.0.1
>> restrict source nomodify
>> broadcastclient
>> manycastserver  224.0.1.1
>> multicastclient 224.0.1.1 key 123 preempt
>> manycastclient  224.0.1.1 key 123 preempt
>> pool pool.ntp.org preempt                # Won't hurt anything if the 
>> internet can't be reached
>> server 10.1.126.204 iburst key 123
>>
>> # If you address the server by name append preempt
>> # Let NTP worry about the minpoll and maxpoll for LAN devices
>>
>> # They should all try to sync to 10.1.126.204
>> #  If they can't reach 10.1.126.204 they should all try to stick together
>>
>> # NTP expects to be run continuously; After a Boot/Reboot/Restart/...
>> #  give the systems 30 minutes to stabilize polls and temperature
>> #   before expecting too much from the ntpq stats
>>
> 30 minutes is more than a little optimistic!  NTPD needs something like 
> ten hours to stabilize with the best time you are going to get.  Thirty 
> minutes after startup is about when NTPD gets days, hours, and minutes
> right.  The next nine and a half hours will be devoted to improve the
> accuracy.

Last night I updated kernel on ntp0.lordynet.org.uk and
system was rebooted at around 23:53.


NetBSD-6
ntpd 4.2.6p5

10 minutes after reboot:
Offset hasn't stabilised and is still 0.000 us but server has
just begun to reply to queries.

Thu Nov 15 00:03:00 GMT 2012
      remote           refid      st t when poll reach   delay   offset 
  jitter
==============================================================================
*SHM(0)          .MSFa.           0 l   20   64  377    0.000    0.096 
  0.279
+ntp1.lordynet.o 81.187.61.74     2 u   28   64   77    0.443   -0.050 
  0.057
+ntp1.aa.net.uk  195.66.241.3     2 u  100  256    1   13.600    0.012 
  0.216
  xxxxxxxxxxxxxxx 131.188.3.222    2 u    5  256    7   24.311   -0.092 
   0.130
  xxxxxxxxxxxxxxx 194.66.31.14     2 u  255  256    3   19.934    3.285 
   0.306
  xxxxxxxxxxxxxxx 195.66.241.2     2 u    9  256    7   13.660   -0.877 
   0.204
  xxxxxxxxxxxxxxx 195.66.241.2     2 u    -  256    7   13.675   -0.312 
   0.239
ntp_gettime() returns code 0 (OK)
   time d44eafb5.c6300000  Thu, Nov 15 2012  0:03:01.774, (.174837786),
   maximum error 304516 us, estimated error 16 us, TAI offset 0
ntp_adjtime() returns code 0 (OK)
   modes 0x0 (),
   offset 0.000 us, frequency -47.095 ppm, interval 4 s,
   maximum error 304516 us, estimated error 16 us,
   status 0x1 (PLL),
   time constant 3, precision 0.000 us, tolerance 496 ppm,
   pps frequency -47.095 ppm, stability 0.000 ppm, jitter 0.000 us,
   intervals 0, jitter exceeded 0, stability exceeded 0, errors 0.


30 minutes after reboot:

Thu Nov 15 00:23:00 GMT 2012
      remote           refid      st t when poll reach   delay   offset 
  jitter
==============================================================================
*SHM(0)          .MSFa.           0 l    4   64  377    0.000   -0.117 
  0.400
+ntp1.lordynet.o 81.187.61.74     2 u    8   64  377    0.417   -0.235 
  0.120
-ntp1.aa.net.uk  195.66.241.3     2 u    7  256   17   13.426    0.364 
  0.493
+xxxxxxxxxxxxxxx 131.188.3.222    2 u  141  256  177   24.311   -0.092 
  0.204
-xxxxxxxxxxxxxxx 194.66.31.14     2 u  121  256  177   19.934    3.285 
  0.285
-xxxxxxxxxxxxxxx 195.66.241.2     2 u  155  256  177   13.372   -1.400 
  0.437
-xxxxxxxxxxxxxxx 195.66.241.2     2 u  137  256  177   13.675   -0.312 
  0.251
ntp_gettime() returns code 0 (OK)
   time d44eb465.042cb210  Thu, Nov 15 2012  0:23:01.016, (.016307390),
   maximum error 3947 us, estimated error 287 us, TAI offset 35
ntp_adjtime() returns code 0 (OK)
   modes 0x0 (),
   offset -116.428 us, frequency -46.406 ppm, interval 4 s,
   maximum error 3947 us, estimated error 287 us,
   status 0x2001 (PLL,NANO),
   time constant 6, precision 0.001 us, tolerance 496 ppm,
   pps frequency -46.416 ppm, stability 0.000 ppm, jitter 0.000 us,
   intervals 0, jitter exceeded 0, stability exceeded 0, errors 0.


David




> 
> This should suggest to you that NTDP should be run 24 hours a day, seven 
> days a week. . . . .
> 
> It's not always possible, but TRY!
> 
> 



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