[ntp:questions] Re: Reading time offset from ntp variables using ntpq

Per Hedeland per at hedeland.org
Fri Feb 17 19:53:32 UTC 2006


In article <fNqdndxUir-sY2jenZ2dnUVZ_tqdnZ2d at comcast.com> "Richard
B. Gilbert" <rgilbert88 at comcast.net> writes:
>Per Hedeland wrote:
>> In article <GJudnUAaJMpAvGjenZ2dnUVZ_sGdnZ2d at comcast.com> "Richard
>> B. Gilbert" <rgilbert88 at comcast.net> writes:
>> 
>>>In that case, I think RFC 1305 needs some clarification.  Page 100 
><snip>
>> Hm, T1 - T4 are defined in figure 14. Of course the .txt version of 1305
>> doesn't have figures, and trying to read the formulas is futile even if
>> you do understand the math. Try the PDF version, e.g. at
>> http://www.faqs.org/rfc/rfc1305.pdf (I guess the PostScript version can
>> also be found somewhere).
><snip>
>
>I have the PDF version! Figure 14 does "define" them but does not 
>connect them to the corresponding timestamps and/or variables in the 
>packet or in the software.

Not formally perhaps, but it does clearly define the timestamps in the
packet:

Originate Timestamp: This is the local time at which the request
 departed the client host for the service host, in 64-bit timestamp
 format.
Receive Timestamp: This is the local time at which the request arrived
 at the service host, in 64-bit timestamp format.
Transmit Timestamp: This is the local time at which the reply departed
 the service host for the client host, in 64-bit timestamp format.

Mapping this description to figure 14 shouldn't be insurmountable...
Mapping to the/some software is clearly outside the scope of any RFC.

--Per Hedeland
per at hedeland.org




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