[ntp:questions] FLL instability

Richard B. Gilbert rgilbert88 at comcast.net
Mon Jan 7 01:27:50 UTC 2013

On 1/6/2013 3:45 AM, Mischanko, Edward T wrote:
>> -----Original Message-----
>> From: questions-
>> bounces+edward.mischanko=arcelormittal.com at lists.ntp.org
>> [mailto:questions-
>> bounces+edward.mischanko=arcelormittal.com at lists.ntp.org] On
>> Behalf Of David Taylor
>> Sent: Sunday, January 06, 2013 2:18 AM
>> To: questions at lists.ntp.org
>> Subject: Re: [ntp:questions] FLL instability
>> On 06/01/2013 06:29, Mischanko, Edward T wrote:
>>> I have "tinker allan 7" in my ntp.conf, as recommended, but I
>> notice that the frequency is adjusting wildly starting with
>> polling at 128 seconds.  Is something wrong with the way FLL is
>> implemented?
>> []
>> Where is this recommended?  URL, please.  I've never had the
>> need to use
>> this tinker myself, so I wonder whether it's some situation
>> which
>> doesn't apply to me.
>> --
>> Cheers,
>> David
>> Web: http://www.satsignal.eu
>> _______________________________________________
>> questions mailing list
>> questions at lists.ntp.org
>> http://lists.ntp.org/listinfo/questions
> [Mischanko, Edward T]
> This was recommended to me on this list several months ago.  I am running my windows client on a corporate LAN and it was suggested that the PLL would not correct fast enough at polling intervals over 128 seconds.  The problem I am seeing is that when FLL is implemented the frequency swings excessively and the offset does not train toward zero.  This would not be needed for setups using GPS/PPS reference clocks.
> Regards,
> Ed

Please use your "Return" or "Enter" key.  MicroSoft will let you write 
lines in excess of 500 characters.  It's rather tough for many of us to 
read it.

You may have other problems but you should expect NTPD to need as long 
as ten hours to settle.  If you are trying to run "9 AM to 5 PM you have 
made some poor choices.  NTPD can take up to TEN HOURS to get the best 
time you can get.  Once it's settled, it should not have any problem 
maintaining synchronization.

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