[ntp:questions] Offset Average (Normal)?

Ron Frazier (NTP) timekeepingntplist at c3energy.com
Tue Mar 13 15:42:35 UTC 2012


On 3/13/2012 10:21 AM, Alby VA wrote:
> On Mar 13, 9:59 am, David Lord<sn... at lordynet.org>  wrote:
>    
>> That seems to be working ok.
>>
>> The NMEA sentences aren't being reported because PPS is being
>> used to condition the system clock.
>>
>> David
>>      
>
>   Okay. My whole understanding of NTP and Clocks is now
> becoming clearer. My apologies, I'm still a n00b.
>
>   So what you are saying is the GPS time via the SureGPS
> device is now being ignored and the time of my machine is
> now being held in check by the PPS signal? If yes, does
> that mean seeing "oGPS_NMEA" is better than seeing
> "*GPS_NMEA"?
>
>   Since I can't find any docs on deciphering the ntpq output,
> I'm trying to understand what the symbols next to each
> entry represent. Some I've found, but maybe you could
> correct me:
>
> o = ???
> * = ??? (My Assumption: preferred time server)
> x = ??? (My Assumption: False Tick - Bad Time)
> + = ??? (My Assumption: Next Best Server for Time)
> - = ??? (My Assumption: Ignore this useless server)
>
>
> ** Sorry for all the questions. Just trying to educate myself on being
> a
> time master too. :)
>
>
>    

Here is where you can find the data on the codes.  I'm a noob too, and 
this info was NOT easy to find, unless you already know where to look, 
which noobs don't.

http://www.eecis.udel.edu/~mills/ntp/html/ntpq.html
http://www.eecis.udel.edu/~mills/ntp/html/decode.html#peer

That second link should take you to the "Peer Status Word" section of 
the page.  Look in the second table in that section under "Select 
Field".  You'll see a short description of the symbols, which they call 
tally codes.

Here's a copy of the table.  Apologies to anyone not viewing this in 
html as it may scramble the table.

Code 	Message 	T 	Description
0 	sel_reject 		discarded as not valid (TEST10-TEST13)
1 	sel_falsetick 	x 	discarded by intersection algorithm
2 	sel_excess 	. 	discarded by table overflow (not used)
3 	sel_outlyer 	- 	discarded by the cluster algorithm
4 	sel_candidate 	+ 	included by the combine algorithm
5 	sel_backup 	# 	backup (more than tos maxclock sources)
6 	sel_sys.peer 	* 	system peer
7 	sel_pps.peer 	o 	PPS peer (when the prefer peer is valid)


Here's some more data.  This is a print screen from the Legend button on 
the Meinberg time server monitor.  I don't know how long this will stay 
in my dropbox, so if you want to keep it, you should save it.

http://dl.dropbox.com/u/9879631/ntpq%20p%20legend.jpg

I agree all this can be very confusing.  Hope this helps

Sincerely,

Ron


-- 

(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such.  I don't always see new messages very quickly.  If you need a
reply and have not heard from me in 1 - 2 weeks, send your message again.)

Ron Frazier
timekeepingdude AT c3energy.com



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