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Re: NTp sources that work in a datacenter (was Re: Is latency equivalent
From: Peter Lothberg <roll () stupi se>
Date: Sat, 31 May 2003 23:01:17 PDT

The receiver do not need to be in the datacenter, there is this thing
called "the internet" that you can hook it up to.

in every PoP to do measurements. In that case, the difficulty isn't in 
measuring one-way latency, it's in synchronizing the time on all the 
servers. And with fairly cheap GPS and CDMA clocks that is a lot 
easier/cheaper than it once was.

      a robust mesh of strat-2 chimers gives one more resilence
      and more accuracy than syncing off a single source.

But what GPS clock can you install in a datacenter? AFAIK, they all 
require roof (or at least window) access in order to install the 
antenna. (At least, all the GPS based ntp servers I've looked at do).
Is that not true of CDMA servers?

      some GPS, some PPS, and an atomic source here and there 
      give great diversity and only a few need roof access.
How have others solved this issue? (Short of owning their datacenters.)

      Use NTP, run most systems as strat-2

Time2.Stupi.SE and Time4.Stupi.SE are both stratum-1 accessable through
the Internet, tracable to UTC-SP (part of TAI) without use of GPS or slaving
to CDMA (that slaves to GPS). 


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