[ntp:questions] Have Pi, have GPS = low powered NTP server?
g8kbv at uko2.co.uk
Mon Jun 11 11:33:03 UTC 2012
<CAMbSiYAFdPaprWsLha07cCui0qBdXULdQjN76VtYY37SQsppdA at mail.gmail.com>,
hart at ntp.org says...
> On Thu, Jun 7, 2012 at 10:30 AM, DaveB <g8kbv at uko2.co.uk> wrote:
> > pi at raspberrypi:~$ ntpq -p
> > remote refid st t when poll reach delay offset jitter
> > ========================================================================
> > *192.168.42.24 .GPS. 1 u 362 1024 377 0.563 0.669 0.284
> > time.xilo.net 126.96.36.199 3 - 5h 1024 0 21.571 13.885 0.000
> > dns0.rmplc.co 188.8.131.52 2 - 5h 1024 0 2019.75 -1000.8 0.000
> > If those delay/offset and jitter figures are in milli seconds (?) could
> > that be down to the USB hosted LAN port on the Pi? The same figures for
> > the BSD box at 192.168.42.24 are 0.000 0.004 and 0.002 respectively, I
> > just remoted into that and checked.
> Yes, having your network behind a USB adapter is going to degrade
> performance compared to a PCI-connected NIC. A half-millisecond delay
> is quite high for 100Mbit LAN. Offset and jitter in the same range
> are to be expected.
> The output of:
> ntpq -c "rv 0 version precision"
> would shed a bit more light on which ntpd version and the time to read
> the clock on that system.
> Dave Hart
pi at raspberrypi:~$ ntpq -c "rv 0 version precision"
version="ntpd 4.2.6p2 at 1.2194-o Sun Oct 17 13:24:55 UTC 2010 (1)"
That's all the output it gave.
And the latest stat's (The other listed servers are still ignored or
are unreachable) after several days left to do it's thing.
pi at raspberrypi:~$ ntpq -p
remote refid st t when poll reach delay offset jitter
*192.168.42.24 .GPS. 1 u 491 512 377 0.559 -0.148 0.102
So by my understanding so far, that would agree with the expected
behaviour of a USB based LAN adapter for this sort of use.
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