[170718] in North American Network Operators' Group
Re: Recommendation on NTP appliances/devices
daemon@ATHENA.MIT.EDU (Saku Ytti)
Fri Apr 4 06:49:19 2014
Date: Fri, 4 Apr 2014 13:48:52 +0300
From: Saku Ytti <saku@ytti.fi>
To: nanog@nanog.org
In-Reply-To: <533E7D72.2010408@studio442.com.au>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On (2014-04-04 20:37 +1100), Julien Goodwin wrote:
> > Meinberg[0] pegs rubidium at ±8ms per year, if you need NTP to do say single
> > direction backbone SLA measurement you want to have microsecond precision.
>
> Those two statements don't go together.
Point I was making is that free-running rubidium is not accurate enough for
QoS measurements of IP core.
> Also outside the HFTers most of us don't care about a few milliseconds
> (sure an extra 50ms can be a pain, but is trivial to measure).
Jitter in backbone is low tens of microseconds, if you want to measure how
that changes over time, free-running rubidium is not going to cut it.
--
++ytti
