[ntpwg] ntpwg Updated NTPv4 Protocol Specification/timestamp location

[STUART VENTERS]

Dave,

>>That's the beauty of it. Herbie and Sue don't care. The delays are still 
>>reciprocal and the fact Sue's delays are one packet longer doesn't matter.

Sadly, this grasshopper appears to have a misconception of what you mean when you say 'the delays are still reciprocal'.  (Or perhaps is having trouble drawing timelines or doing algebra.) Please help me understand where I strayed from the path.

If the 'the delays are still reciprocal' and the client and server clocks are aligned, then shouldn't the offset equation equal zero?


Regards,

Stuart


ps, From RFC-1305 section 3.4.4, setting i=4, offset = ((T2-T1) + (T3-T4))/2.
    From the example,   T2-T1 = T3-T4 = -(packet time)
    offset = -(packet time)

pps, My working definition for matching reciprocal delays was that 
     the propagation/queueing/transmission delay between T1 and T2 
     is the same as between T3 and T4.
     Where same means same sign and magnitude.
     (In the example, they appear to be same magnitude, but different sign.)

ppps, It's interesting that in this example, T2 happens before T1.
      Appendix H, section 8.4, says this can't happen in our universe.
      (Perhaps I should consider this clue further.)