[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 
>> and
>> then run your test.
>>
>> H
> 
> 
> 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 
  jitter
==============================================================================
*sunblok         .GPS.            1 u  453 1024  377    0.490    0.006 
  0.030


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




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