On 26/11/2012 23:59, David Woolley wrote:
Offsets should be randomly distributed between + and - signs. If they
are all of one sign, you are not locked up or there is a bug. They
should be of s similar magnitude to the jitter.
They may not be evenly distributed, because of limitations of the
network, but they must be spread across zero.
On the card which is synced purely to LAN servers, over a day the mean
offset of the FreeBSD stratum-1 server (the selected sync source) is
0.000 ms, and that of two Windows stratum-1 servers is 0.014 ms. The
mean jitter is 0.041 ms (FreeBSD) and 0.048 and 0.280 ms (Windows). The
offset of WAN-based pool servers was in the region of 2 - 8 ms.
On the card with the PPS source, the mean offset of the other servers is
-0.020 ms (FreeBSD) and -0.008 ms (both Windows). Mean jitter is 0.230
ms (FreeBSD) and 0.036 ms and 0.230 and 0.047 ms (Windows). The offset
of WAN-based pool servers was in the region of 2 - 14 ms.
THe WAN is vai a cable modem connection, rather asymmetrical at 30 Mb/s
down and 3 Mb/s up.
--
Cheers,
David
Web: http://www.satsignal.eu
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