Re: NTP Sync Issue Across Tata (Europe)

[Mel Beckman <mel () beckman org>]

Masataka,

To be useful, any atomic clocks you operate must be synchronized to a Stratum Zero time source, such as GPS. Such 
clocks are useful when you need exceptional accuracy, such as for Building Integrated Timing Service (BITS), but unless 
they’re synchronized you can’t coordinate time-sensitive activities such as digital certificate validation with anyone 
else on the Internet.

From 
https://www.gps.gov/applications/timing/<https://www.gps.gov/applications/timing/#:~:text=GPS%20receivers%20decode%20these%20signals,owning%20and%20operating%20atomic%20clocks.>


Each GPS satellite contains multiple atomic clocks that contribute very precise time data to the GPS signals. GPS 
receivers decode these signals, effectively synchronizing each receiver to the atomic clocks. This enables users to 
determine the time to within 100 billionths of a second, without the cost of owning and operating atomic clocks.

Precise time is crucial to a variety of economic activities around the world. Communication systems, electrical power 
grids, and financial networks all rely on precision timing for synchronization and operational efficiency. The free 
availability of GPS time has enabled cost savings for companies that depend on precise time and has led to significant 
advances in capability.

-mel via cell

On Aug 7, 2023, at 10:04 PM, Masataka Ohta <mohta () necom830 hpcl titech ac jp> wrote:

Forrest Christian (List Account) wrote:

In the middle tends to be a more moderate solution which involves a mix of
time transmission methods from a variety of geographically and/or network
diverse sources.  Taking time from the public trusted ntp servers and
adding lower cost GPS receivers at diverse points in your network seems
like a good compromise in the middle.  That way,  only coordinated attacks
will be successful.

Instead, just rely on atomic clocks operated by you. They are not
so expensive (several thousand dollars) and should be accurate
enough without adjustment for hundreds of years. There can be no
coordinated attacks. They may be remotely accessed through
secured NTP.

                   Masataka Ohta