[ntp:questions] frequency adjusting only
Unruh
unruh-spam at physics.ubc.ca
Sat May 3 04:41:54 UTC 2008
"David L. Mills" <mills at udel.edu> writes:
>Brian,
>The longest delay NTP response was from the Moon, as simulated at JPL.
>Next step is the Mars orbiters and then the rovers. JPL discovered the
>max distance threshold had to be increased to handle the Moon delay.
Thats only a few sec.
And it is symmetrical. Could probably still get usec resolution.
>The longest lived NTP headbanger was when I used ARPAnet IMP 29 back in
>the late 70s. The banger continued without response until the ARPAnet
>was dismantled in the early 90s. There are folks that have been banging
>on our racket.udel.edu at its 128.4.1.1 address since 1981.
>So far, not response has arrived before the request was sent. The code
>even checks for that. I'll let you know.
>Dave
>Brian Utterback wrote:
>> David L. Mills wrote:
>>
>>> Suspecting such could be the case between NTP servers and clients, I
>>> designed an experiment to detect such things and found small but
>>> significant LRD effects with lags up to TWO WEEKS! At short lags up to
>>> several network turns this can be explained by packet lengths,
>>> buffering, retransmissions, etc., but at much longer lags you have to
>>> look for routing flaps, provisioning changes, etc.
>>>
>>
>> Dave, are you saying that you saw an instance of a NTP response arriving
>> 2 weeks after the request was sent?
>>
>> Brian Utterback
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