[58790] in North American Network Operators' Group
Re: NTp sources that work in a datacenter (was Re: Is latency
daemon@ATHENA.MIT.EDU (Peter Lothberg)
Sun Jun 1 02:04:19 2003
Date: Sat, 31 May 2003 23:01:17 PDT
From: Peter Lothberg <roll@stupi.se>
To: bmanning@karoshi.com
Cc: steve@expertcity.com (Steve Francis), Michael.Dillon@radianz.com,
nanog@merit.edu
In-Reply-To: Your message of Wed, 14 May 2003 08:28:37 -0700 (PDT)
Errors-To: owner-nanog-outgoing@merit.edu
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).
-P
