[ntp:questions] NTPv4 Peer Event Codes - secret decoder ring sought

Joe Gwinn joegwinn at comcast.net
Fri Mar 19 22:56:54 UTC 2010


Dave M,

At 9:48 PM +0000 3/19/10, David Mills wrote:
>Joe,
>
>That's a typo; event 16 does not exist. Glad you caught that.

Ahh.  So the other codes are as stated, and zero is not used.  Glad 
to be of help.

Joe


>Dave
>
>Joseph Gwinn wrote:
>
>>Dave,
>>
>>In article <4BA2C1FF.3060803 at udel.edu>, David Mills <mills at udel.edu> wrote:
>>
>>
>>>Joe,
>>>
>>>You and Dave are working way too hard. The bits and pieces are 
>>>documented on the ntpq page and on the Event Messages and Status 
>>>Codes page.
>>>   
>>>
>>
>>This would be 
>><http://www.eecis.udel.edu/~mills/ntp/html/decode.html#peer>, which 
>>I didn't know about, but is exactly what I seek.  And it wasn't a 
>>secret after all.
>>
>>But I have a question, a homework example, and a suggestion.
>>
>>First the question:  The Code field of the Peer Status Word is 4 
>>bits wide, and yet codes are defined for values from 1 to 10 hex 
>>(decimal 16), which doesn't quite map.  How does the code value fit 
>>into the field?  Wraparound, so 10 (TAI) becomes zero?
>>
>>
>>The homework example:  The PSW word that started this exercise is 
>>"963a".  If I understand, this word decodes as follows:
>>
>>Status field - host_reachable plus persistent_association
>>
>>Select field - system_peer (gets the star)
>>
>>Count field - 3
>>
>>Code field - become system peer (assuming code values are truncated 
>>to 4 bits, so hex 10 becomes 0) 
>>And 9614 decodes to host_reachable plus persistent_association, 
>>system_peer (gets the star), count=1, and server_reachable.
>>
>>
>>And the suggestion:  I was misled by some of the NTPv4 
>>documentation, specifically the NTPv4 peerstats file documentation 
>>in <http://www.eecis.udel.edu/~mills/ntp/html/monopt.html>. 
>>The note under the table defining peerstats record fields reads 
>>"The status field is encoded in hex format as described in Appendix 
>>B of the NTP specification RFC 1305".  This is no longer really 
>>true, as you discuss below.  In particular, codes exceeding 5 are 
>>not defined in 1305, and some of the definitions appear to have 
>>changed (or at least have been clarified) so it would be helpful to 
>>add a pointer to 
>><http://www.eecis.udel.edu/~mills/ntp/html/decode.html#peer> to 
>>monopt.html.
>>
>>
>>
>>>RFC-1305  was written in 1992. It's been 18 years since then, so 
>>>you should expect changes from time to time. Changes are not done 
>>>lightly; they reflect updates in the algorithms and interpretation 
>>>of the statistics and state variables. If the interpretation  has 
>>>not changed, the name and code have not changed. If it has been 
>>>changed or has become obsolete, the name is not reused.
>>>   
>>>
>>
>>This is good.  There is far too much existing base to do it any other way.
>>
>>Thanks,
>>
>>Joe Gwinn
>>
[snip]




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