); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Hi Hal:
I'm in Califoria on the other side of the country from Atlanta, GA where the big dish is located. Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com Hal Murray wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] RETRY > > > >>I'm curious about the stability of Ping timing between high quality >>NTP servers. Is it the case that a histogram will show different >>times because the path may be different between the two servers but >>the spread for any given path would be quite small because of the >>quality of the timing? > > > NTP measures the transit time in both directions. It assumes symmetry and > calculates the offset as half the difference and uses that to adjust the > local clock. > > Assuming you have good clocks on both ends: > > If you plot the offset vs round trip time, you get an arrow pointing left. > The point (blob) of the arrow is the best case. The edges of the arrow are > due to queuing delays in one direction or the other. You also get some > scattered points trying to fill in the arrow from queuing delays in both > directions. > > If you plot round-trip time vs time of day, you can see occasional jumps > where the network path changes, or somebody starts a big download that fills > up one side of a pipe for a while. > > > >>Or if I was pinged would the wander of the satellite in the link show >>up or is my stock PC so crude it swamps the satellite wander? >>148.78.32.98 or 148.78.32.97 not sure if those are visible on the net. > > > ping just gives you the round trip time. I'm not sure where ntp fits in. > > It's reasonable to get ntp with a GPS clock running in the few microsecond > range. I'd guess you might see satellite wander if that covers a few miles. > It might be hard to see in all the other network noise. > > Where are you located (packet hops, not crow fiies) relative to the satellite > ground stations? > > > > > > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
