[ntp:questions] Re: offset values from ntpq and ntptrace

Tanguy.ropitault at gmail.com Tanguy.ropitault at gmail.com
Fri Mar 31 08:25:47 UTC 2006


Typically, here comes my results...
I have one server wich is synchronized on a NTP pool.ntp.org server's
projet. So ntptime gives:

[root at linux2400 ntp]# ntptime
ntp_gettime() returns code 0 (OK)
  time c7d76439.c31ea000  Fri, Mar 31 2006 10:18:01.762, (.762186),
  maximum error 123497 us, estimated error 56418 us
ntp_adjtime() returns code 0 (OK)
  modes 0x0 (),
  offset -1717.000 us, frequency 28.921 ppm, interval 4 s,
  maximum error 123497 us, estimated error 56418 us,
  status 0x1 (PLL),
  time constant 2, precision 1.000 us, tolerance 512 ppm,
  pps frequency 0.000 ppm, stability 512.000 ppm, jitter 200.000 us,
  intervals 0, jitter exceeded 0, stability exceeded 0, errors 0.

So if i understand, my NTP server is 56418us accurated compared to the
server on wich it is synchronising? So I don't know compared to the
reference clock??? And 56418us is a good value?

On my client synchronized on my NTP server, ntptime gives:
root at dol600 ntp]# ntptime
ntp_gettime() returns code 0 (OK)
  time c7d761ba.44123000  Fri, Mar 31 2006 10:07:22.265, (.265903),
  maximum error 210968 us, estimated error 2013 us
ntp_adjtime() returns code 0 (OK)
  modes 0x0 (),
  offset 677.000 us, frequency -2.616 ppm, interval 4 s,
  maximum error 210968 us, estimated error 2013 us,
  status 0x1 (PLL),
  time constant 2, precision 1.000 us, tolerance 512 ppm,
  pps frequency 0.000 ppm, stability 512.000 ppm, jitter 200.000 us,
  intervals 0, jitter exceeded 0, stability exceeded 0, errors 0.

2013us is a good number? I know that it depends on my configuration but
I have read that normally, on a LAN, the number could be 50us so I find
that 2013 is too high... can you help pe?




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