On 2011-09-01, Miguel Gon?alves <[email protected]> wrote: > Hi all! > > I have two internal FreeBSD with GPS receivers attached (Garmin 18 LVC: > 10.0.2.10 / Sure Evaluation Board:10.0.2.9). Both machines are on the same > LAN segment (VLAN). > > For redundancy, I've configured a Cisco switch as a stratum 2 server. Here's > the relevant information: > > $ ntpq -pcrv 10.0.2.254 > remote refid st t when poll reach delay offset > jitter >============================================================================== > +ntp0.as34288.ne .PPS. 1 u 814 1024 377 72.750 -1.084 > 0.780 > +canon.inria.fr .GPSi. 1 u 399 1024 377 55.110 0.218 > 0.400
What are those machines? You have names rather than IP addresses. Are they your pps machines? > *ntp1.inrim.it .CTD. 1 u 677 1024 377 64.540 -0.284 > 0.080 > +ntp-p1.obspm.fr .TS-3. 1 u 205 1024 377 57.040 1.004 > 1.450 > -metasweb01.admi .HBGi. 1 u 841 1024 377 74.600 -4.075 > 0.200 > associd=0 status=0600 leap_none, sync_ntp, no events, unspecified, > system="cisco", leap=00, stratum=2, rootdelay=64.540, > rootdispersion=1.370, peer=7253, refid=193.204.114.232, > reftime=d209d7f4.6500bcf0 Thu, Sep 1 2011 11:07:48.394, poll=10, > clock=d209da99.b57d6483 Thu, Sep 1 2011 11:19:05.708, phase=-0.628, > freq=9.60, error=0.95 > > I have another machine (Linux, CentOS 5.6) that is a client to these stratum > 1 FreeBSD machines. Here's the relevant information: > > $ ntpq -pcrv 10.0.2.2 > remote refid st t when poll reach delay offset > jitter >============================================================================== > +10.0.2.10 .GPS. 1 u 211 256 377 0.159 -0.139 > 0.350 > *10.0.2.9 .GPS. 1 u 71 256 377 0.166 -0.136 > 0.468 That is a huge offset for being on the same lan, and for being only .15ms away. > +10.0.2.254 193.204.114.232 2 u 22 256 377 0.560 1.557 > 0.082 > li298-159.membe 217.20.44.6 2 u 69 256 377 51.718 -1.200 > 0.919 > associd=0 status=06f4 leap_none, sync_ntp, 15 events, freq_mode, > version="ntpd [email protected] Sat Dec 19 00:58:16 UTC 2009 (1)", > processor="i686", system="Linux/2.6.18-238.19.1.el5", leap=00, stratum=2, > precision=-20, rootdelay=0.166, rootdispersion=11.880, peer=24216, > refid=10.0.2.9, reftime=d209da8a.8b5bd2c6 Thu, Sep 1 2011 11:18:50.544, > poll=8, clock=d209dad1.3849eae8 Thu, Sep 1 2011 11:20:01.219, state=4, > offset=-0.033, frequency=44.545, jitter=0.653, noise=0.030, > stability=0.007, tai=0 > > I've checked 10.0.2.9 and 10.0.2.10 and they are usually less than 5 us > apart: Fine. That is what your results from 10.0.2.2 suggest as well. > > tick# ntpdate -p8 -q tock > server 10.0.2.9, stratum 1, offset -0.000004, delay 0.02577 > 1 Sep 10:23:45 ntpdate[3537]: adjust time server 10.0.2.9 offset -0.000004 > sec That probably says more about the symmetry of the path than the offset of the machine. > tick# ntpdate -p8 -q tock > server 10.0.2.9, stratum 1, offset -0.000004, delay 0.02577 > 1 Sep 10:23:47 ntpdate[3538]: adjust time server 10.0.2.9 offset -0.000004 > sec > tick# ntpdate -p8 -q tock > server 10.0.2.9, stratum 1, offset -0.000003, delay 0.02577 > 1 Sep 10:23:49 ntpdate[3539]: adjust time server 10.0.2.9 offset -0.000003 > sec > tick# ntpdate -p8 -q tock > server 10.0.2.9, stratum 1, offset -0.000005, delay 0.02577 > 1 Sep 10:23:50 ntpdate[3540]: adjust time server 10.0.2.9 offset -0.000005 > sec > > What I find strange is the offset of the stratum 2 server above (10.0.2.2) > to the other stratum 2 machines (Cisco and external one that is 50 ms away). > > Are my GPS clocks OK? Does this happen due to the network latency? Are my > stratum 2 servers OK? Your GPS seems to be consistant with each other ( that is all one can say without another time source to compare them to). Your offsets are large compared with the delay times ( was the machine recently heated up due to working harder?) > > Can anyone help? > > Thanks! > > Miguel _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
