nanog mailing list archives

Re: Cost-effectivenesss of highly-accurate clocks for NTP


From: Mel Beckman <mel () beckman org>
Date: Mon, 16 May 2016 03:12:51 +0000

Joe and Eric,

It's frustrating how far public safety technology lags behind what Industry can actually deliver. It's the same in 
aviation. Institutions are slow to adopt new tech due to fears about reliability, and and unwillingness to take any 
risk at all.  So PS and aviation capabilities lag horribly. This is why commercial pilots, tired of waiting on the FAA, 
are buying their own tablets and running non-certified navigation tools. And police officers use cellular data 
connection with VPN to query wants and warrants databases. 

-mel beckman

On May 15, 2016, at 5:28 PM, joel jaeggli <joelja () bogus com> wrote:

On 5/15/16 10:05 AM, Eric S. Raymond wrote:
Mel Beckman <mel () beckman org>:
The upshot is that there are many real-world situations where
expensive clock discipline is needed. But IT isn't, I don't think,
one of them, with the exception of private SONET networks (fast
disappearing in the face of metro Ethernet).

Thank you, that was very interesting information.  I'm not used to thinking
of IT as a relatively low-challenge environment!

You're implicitly suggesting there might be a technical case for
replacing these T1/T3 trunks with some kind of VOIP provisioning less
dependent on accurate time synch.  Do you think that's true?

APCO  and TETRA trunked radio  are mature systems, they do carry data,
but are somewhat lower bandwidth. Being TDM they are dependent on
accurate clocks.

LTE systems are used or envisioned being used for high bandwidth
applications.





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