On 2011-09-02, Miguel Gon?alves <m...@miguelgoncalves.com> wrote: > Comments bellow... > > On 2 September 2011 00:47, unruh <un...@wormhole.physics.ubc.ca> wrote: > >> On 2011-09-01, Miguel Gon?alves <m...@miguelgoncalves.com> wrote: >> > Hi! >> > >> > Thanks for your reply. My comments bellow. >> > >> > On 1 September 2011 18:24, unruh <un...@wormhole.physics.ubc.ca> wrote: >> > >> >> On 2011-09-01, Miguel Gon?alves <m...@miguelgoncalves.com> 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? >> > >> > >> > No. This is a stratum 2 server and it gets the time from stratum 1 >> servers >> > thus the names and not IP addresses. >> >> What I am asking is what the mapping is between these names and the >> numbers you have later. I assume that some of those names are the same >> machine as the IP addresses you list below but We do not have that >> infomation. >> > > Which numbers? > > 10.0.2.254 is a stratum 2 server that gets time information from outside > servers (I've included the information). canon.inria.fr is a server in > France that has a GPS clock receiver AFAIK. > > 10.0.2.254 is just a Cisco switch that I set up internally for comparison to > the the stratum 1 servers (10.0.2.9 and 10.0.2.10). > > 10.0.2.2 is another server (Linux, CentOS) that gets time from 10.0.2.9, > 10.0.2.10 and 10.0.2.254. I've written all this before. I thought I was > clear enough.
Nope. It is completely unclear to me what your question is. Your 10.0.2.254 is an outside switch. > > >> > $ ntpq -p 10.0.99.99 >> > remote refid st t when poll reach delay offset >> > jitter >> >> >============================================================================== >> > *10.0.2.10 .GPS. 1 u 21 256 377 0.173 0.196 >> > 0.008 >> > +10.0.2.9 .GPS. 1 u 93 256 377 0.175 0.191 >> > 0.014 >> > +10.0.2.254 81.94.123.16 2 u 149 256 377 0.583 -6.884 >> > 0.152 This tells me that your two GPS receivers are consistant with each other, but I have no idea why the offset is larger than the delay, and why the offsets are so large. On a lan, the offsets should be a factor of 20 or so less than what you are getting here. That the external router is 7 ms out just tells me that it is really poorly synced with the outside world. >> > >> > This is a FreeBSD embedded PBX machine running Asterisk. The machine is >> > mostly idle. What kind of offsets should I get with local machines? >> >> in the 10s of usec range max. Certainly less than the delay. >> > > tens of usec is good... Anyone here which can explain why NTP isn't getting > that? How could we? Maybe you are running a virtual BSD machine, and thus the clocks are wonkey. Maybe you have lousy hardware. Who knows. > > >> > Assuming ntp04, ntp05 and ntp06 are on the same LAN I see offsets higher >> > than 100 us. Is it possible to decrease these numbers? >> >> Sure. all my systems have offsets in the 10us range-- on the same lan >> as my time server. >> Mind you I do use chrony, not ntpd but even ntpd should be in a few 10s >> of usec. > > > Can ntpd really get there? I'll try to query some good public servers to see > what others are getting... Sure it can. It can get better than 30us. But why you are not getting it is impossible for us to say. > >> All my machines are Linux machines. Linux is fine for timekeeping. >> > > OK. No criticism intended. I'm just a BSD guy. _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions