NTp sources that work in a datacenter (was Re: Is latency equivalent

bmanning at karoshi.com bmanning at karoshi.com
Wed May 14 15:28:37 UTC 2003

> >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


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