[ntp:questions] ntpd: time reset problem

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Tue Sep 15 05:05:54 UTC 2009

>> IF the latency is known to be symmetric ( which it is
>>  on an interplanetary system) then large latency is no
>>  problem.
>I don't see how they are likely to have symmetric latency.
> e.g.
>  The earths orbital velocity is something like 67k mph?
>   mars orbital velocity is something like 54k mph?
>  If you were to send a message, and wait for a response,
>   the planets would by significantly closer or farther
>   apart when the response was sent?
>   {Then again I know almost nothing about astrophysics.}

It's close to symmetric because there aren't any queueing

Your point is valid.  It can be corrected for.

If you are really serious, you have to correct for relativity.
There is a blue shift from Mars to Earth since Earth is deeper
in the Sun's gravity well.  (Or something like that.)

These are my opinions, not necessarily my employer's.  I hate spam.

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