[ntp:hackers] Question about USB3... anyone played with it?

Gary E. Miller gem at rellim.com
Wed Dec 11 21:53:21 UTC 2013


Yo Harlan!

On Wed, 11 Dec 2013 21:15:39 +0000
Harlan Stenn <stenn at ntp.org> wrote:

> "Gary E. Miller" writes:
> > Greg Troxel <gdt at ir.bbn.com> wrote:
> > 
> > > I have a GR601-W, which seems to have a 1ms variation.
> > 
> > Yeah, can't call that horrible, that is better than you'll get
> > on GigE sitting next to a Stratum 1.
> 
> Really?  I'm used to sub-msec (like under .25) offsets and jitter with
> GigE LANs and S1 servers.

I can only get that good with a GPS at both ends.  Sure it may show that
good off and on, but when the servers gets busy, the net gets busy, or
the temp drifts I can't count on it.

> And to make sure I'm on the same page as y'all, what is "variation"?

That is my weasel wording to avoid saying if I'm seeing offset, jitter,
wander or various combinations of the above.

As a practical matter the 'jitter' as reported by ntpq is always better for
me with at least a GR-601W or better on both ends.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701
	gem at rellim.com  Tel:+1(541)382-8588
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