I ran an experiment designed to compare the times across the network between two
Heath GC-1000 WWV clocks, one near Washington, DC, and the other in Ann Arbor,
Michigan. The experiment collected ICMP Timestamp messages from each site for
a nine-hour overnight period when both clocks were synchronized to the 5-MHz
WWV signal, at least most of the time. The collected data was then reduced and
The results show the two clocks are in very close agreement and exhibit the same
three-minute sawtooth-looking error function as I described earlier. The peak-peak
amplitude of the error function is about 100 ms and the mean error is about 30 ms.
relative to our WWVB reference clock. Not bad at all.
The graphs themselves are in Sun rasterfile format and can be displayed using
the screenload program for the Sun. The files are on dcn9.arpa called umi.bit
(Ann Arbor) and dcn.bit (Washington) and are accessible with anonymous FTP.
Thanks to Milo Medin (firstname.lastname@example.org) for polishing up our Sun-resident NTP
server and rehosting under 4.3bsd. The server now runs in dcn9.arpa, orion.arpa
ames.arpa and trantor.umd.edu, as well as assorted fuzzballs.
This archive was generated by hypermail 2.0b3 on Thu Mar 09 2000 - 14:35:38 GMT