Hi,
I have 2 stratum 1 Freebsd boxes in roughly the same configuration,
ie a network stratum 1 peer and a Cs 1PPS ; they are working
ok afaics, but both report a sys_jitter of 0.001907 that seem to be an
impasable lower limit. Does anyone have some link/explanation
regarding the mechanism behind this limit ?
Thank you in advance.
Below are ntpq -p and ntpq -c rv output for both machines :
saturne :
remote refid st t when poll reach delay offset jitter
==============================================================================
oPPS(0) .PPS. 0 l 25 64 377 0.000 0.001 0.002
+192.168.12.7 .PPS. 1 s 31 64 377 0.366 0.042 0.040
*ntp-p1.obspm.fr .TS-4. 1 s 123 64 372 11.399 0.012 0.378
associd=0 status=0115 leap_none, sync_pps, 1 event, clock_sync,
version="ntpd 4.2.8@1.3265-o Wed Jan 7 15:31:43 UTC 2015 (1)",
processor="i386", system="FreeBSD/10.1-RC3", leap=00, stratum=1,
precision=-19, rootdelay=0.000, rootdisp=1.375, refid=PPS,
reftime=d87b1e49.6f35f1e4 Tue, Feb 3 2015 10:15:37.434,
clock=d87b1e63.2e1257cd Tue, Feb 3 2015 10:16:03.179, peer=5700, tc=6,
mintc=3, offset=0.000750, frequency=-196.055, sys_jitter=0.001907,
clk_jitter=0.002, clk_wander=0.000, tai=35, leapsec=201507010000,
expire=201512280000, host="saturne.obs-besancon.fr", flags=0x80003,
digest="md5", signature="md5WithRSAEncryption", update=201501291235,
cert="saturne.obs-besancon.fr saturne.obs-besancon.fr 0x1",
until=201601151330
192.168.12.7:
remote refid st t when poll reach delay offset jitter
==============================================================================
oPPS(0) .PPS. 0 l 5 64 377 0.000 -0.001 0.002
*saturne.obs-bes .PPS. 1 s 44 64 177 0.362 -0.033 0.029
ntp-p1.obspm.fr .INIT. 16 s - 1024 0 0.000 0.000 0.000
associd=0 status=01f8 leap_none, sync_pps, 15 events, no_sys_peer,
version="ntpd 4.2.8@1.3265-o Wed Jan 14 20:49:48 UTC 2015 (1)",
processor="i386", system="FreeBSD/10.1-RELEASE", leap=00, stratum=1,
precision=-19, rootdelay=0.000, rootdisp=1.090, refid=PPS,
reftime=d87b1c7d.57c3637c Tue, Feb 3 2015 10:07:57.342,
clock=d87b1c83.53a0827a Tue, Feb 3 2015 10:08:03.326, peer=28975, tc=6,
mintc=3, offset=-0.000736, frequency=-2.064, sys_jitter=0.001907,
clk_jitter=0.002, clk_wander=0.000, tai=35, leapsec=201507010000,
expire=201512280000
--
François Meyer Tel : (+33) 3 81 66 69 27 Mob : 6 27 28 56 83
Observatoire de Besancon - BP1615 - 25010 Besancon cedex - FRANCE
Institut UTINAM * Universite de Franche-Comte * CNRS UMR 6213 ***
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