[ntp:questions] Re: soekris 4501 that won't settle
Richard B. Gilbert
rgilbert88 at comcast.net
Tue Mar 21 16:01:01 UTC 2006
Joshua Coombs wrote:
> "Harlan Stenn" <stenn at ntp.isc.org> wrote in message
> news:ywn9d5ggjpp1.fsf at ntp1.isc.org...
>>>>> In article <P7adnXboCdsf4oLZRVn-pw at gwi.net>, "Joshua Coombs"
>>>>> <jcoombs at gwi.net> writes:
>> Joshua> ... I was initially locking the poll interval at 2048 seconds
>> Joshua> as this is a test setup and I both wanted to verify the
>> stability of
>> Joshua> the 4501 and keep from abusing the remote servers I was
>> using. I've
>> Joshua> lowered it to 512 seconds to see if that improves things...
>> I recommend you leave the default settings for the poll interval alone
>> then run your test.
> Tried that and let it run last night. It would bounce the poll interval
> between 256 and 512 seconds. PLL freq was much more stable, but I don't
> like that it wasn't confidant enough to crank up the poll interval.
> Joshua Coombs
It's behaving as designed! My guess would be that your network
connection to your server is none too good; e.g. high values of delay
and/or jitter. If you were to configure a server on your local network
with a GPS reference clock, I think you would find that your client
would settle down with a long poll interval.
sunblok_$ ntpq -p sunspot
remote refid st t when poll reach delay offset
*sunblok .GPS. 1 u 453 1024 377 0.490 0.006
Sunblok, as you see, is a stratum one server with a GPS reference clock.
It's a Sun Ultra 10. Sunspot is an Ultra 5 three feet away in
geographical space and and 12 feet of cable plus a cheap 100 megabit
Ethernet switch in network space. It is serenely confident that it
knows what time it is because it has a stable and consistent source.
If you could synch to sunblok your results would not be anywhere near as
good because the network between your site and mine would introduce a
bunch of random phase noise.
I suppose there is not much you can do to improve your network
connection but you might be able to find a better server or set of servers
More information about the questions