[LEAPSECS] current / future state of UT1 access?

Rob Seaman seaman at lpl.arizona.edu
Mon Mar 19 13:30:19 EDT 2018


I appreciate the feedback from everybody on the UT1 NTP issue. I have
yet to successfully connect from campus and possibly Martin's comment
applies since there are a lot of telescopes and astronomers here working
for several observatories. Somebody else on this end may be bogarting
the NIST UT1 (though we get through fine to their UTC servers).

The issue has come up now since a colleague asked about best practices
for access to UT1. In the mean time he's implemented yet another
internet retrieval of Bulletin A. Perhaps it needs to be stressed again,
astronomers require access to both Universal Time and Atomic Time.

The NIST UT1 server is not currently useful for our purposes. Perhaps a
UT1 pool will make sense at some point? If the NIST servers are all
loaded "sky high", is there any plan to mitigate this through data
center / networking best practices? We have seen their other servers'
reach faltering at this end, too.

Thanks!

Rob

--


On 3/19/18 7:43 AM, Martin Burnicki wrote:
> Please note you need to take care if you have several nodes behind a NAT
> router that poll the same server. From the server's point of view it
> looks like all the requests from the nodes behind the router seem to
> come from the same (public) IP address, so a particular node on the NAT
> subnet may receive even less replies.

On 3/19/18 9:48 AM, Poul-Henning Kamp wrote:
>> You can simply test this if you run "ntpdate -d -p1 <hostname>"
>> repeatedly. When I try this for a NIST server here from Germany I only
>> receive a reply occasionally, and in most cases I don't.
> Last I heard about it, the packet load on the NIST servers were
> sky high so I am not the least surprised...
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