RE: [10GBT-Modeling] RE: [10GBT-Cabling] [10GBASE-T] a channel capacity estimation program for your evaluation
As I understand it, the reason we subdivided into a modeling ad-hoc and
a cabling adhoc is to allow parallel work. As such, I will continue
this discussion on the modeling ad-hoc reflector, which, to date, we're
not using well. You haven't answered my basic question, which is, while
we work the alien NEXT in parallel, what beyond that are your barriers
to technical feasibility. As a group, we must begin the flushing out of
technical feasibility issues. That way the group can address them
efficiently.
In my experience, standards bodies make progress by finding consensus on
the easier issues first and working the difficult ones over time. In
that spirit, let us find some common ground. Otherwise, the discussion
is simply a distraction, and will make progress only at the slowest
possible pace.
Please let us switch now to the appropriate ad-hoc reflector to make
some progress.
-george
George Zimmerman
gzimmerman@solarflare.com
tel: (949) 581-6830 ext. 2500
cell: (310) 920-3860
-----Original Message-----
From: xichen@marvell.com [mailto:xichen@marvell.com]
Sent: Monday, February 24, 2003 1:28 PM
To: George Zimmerman
Cc: stds-802-3-10GBT-Cabling@ieee.org;
stds-802-3-10GBT-Modeling@ieee.org; stds-802-3-10GBT@ieee.org
Subject: RE: [10GBT-Modeling] RE: [10GBT-Cabling] [10GBASE-T] a channel
capacity estimation program for your evaluation
First I believe that the program can be modified to take the selected
measured channel models instead of the channel limit used now. But I
wish
that before you distribute this updated program to this group, there
should
be a consensus in the group on the channel model itself first.
Otherwise,
it will cause further confusion in this group if we need to change the
channel model later.
A lot people in this group have realized that ANEXT is not a easy
problem.
First there does not exist a standard about ANEXT. Of course, as you
said,
there will be one sooner or later. Second, even the standard is
available
now, the technical feasiblility of system under current assumputions
(distance, cable type, etc.) definitely needs further evaluation. What
the
standard under investigation needs to support (distance, cable type,
etc.)
therefore is still a question at large.
The most important thing is to let the group understand the problems
well
and then get a solution that will satisfy most of us, if not all.
Xiaopeng
Marvell Semiconductor
"George Zimmerman" <gzimmerman@solarflare.com>@majordomo.ieee.org on
02/24/2003 12:23:12 PM
Sent by: owner-stds-802-3-10gbt-cabling@majordomo.ieee.org
To: <stds-802-3-10GBT-Cabling@ieee.org>,
<stds-802-3-10GBT-Modeling@ieee.org>, <stds-802-3-10GBT@ieee.org>
cc:
Subject: RE: [10GBT-Modeling] RE: [10GBT-Cabling] [10GBASE-T] a
channel
capacity estimation program for your evaluation
I want to understand your response. I hear you saying that you now
agree
that real channels (what we call measurement-based models) instead of
limit
lines will produce better results. Hence the importance of the cabling
group completing that work. Modifying the code to take a file of
measurement samples would be worthwhile in that regard. We have
modified
your code to do this, but want to test it & make sure that it is correct
before sending to the reflector. You should see something shortly.
Secondly, the modeling of alien NEXT will be challenging, and you want
to
see that done by the channel group before we move forward. Does that
mean
that you are on-board with technical feasibility with that one
exception?
Otherwise we should work on the other issues in parallel with the
cabling
group. Such an effort would not be wasted, because surely you could see
a
circumstance where a cable quality test could be used to address the
variation in alien NEXT, qualify cables as some significant distance, if
not 100m, and therefore there is a technically feasible 10GBASE-T in our
grasp.
George Zimmerman
gzimmerman@solarflare.com
tel: (949) 581-6830 ext. 2500
cell: (310) 920-3860