Charles,
Please point out the definition "improved FR-4" in the IEEE specification.
Ultimately, in IEEE 802.3ap the Study Group defined what that meant (well actually Joel, but it was approved by the Study Group). This was done in order to assess whether the objectives were met.
If the definition had found its way into the specification I would be more inclined to support your point below. However, it wasn't, and ultimately the informative channel model provided the attenuation / insertion that had to be targeted. Then it is up to the implementer, who can use whatever material they choose.
Regards,
John
-----Original Message-----
From: Charles Moore [mailto:charles.moore@xxxxxxxxxxxxx]
Sent: Thursday, February 24, 2011 3:11 PM
To: STDS-802-3-100GCU@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GCU] WebPage Updates
joel,
Yes but. We used "improved FR-4" to make 10GBASE_KR work. We are
going to need something better if we want to run 2.5x faster and
1.0-0.75x as far. What can we call that? Is it "more improved FR-4"?
charles
|--------------------------------------------------------------------|
| Charles Moore
| Avago Technologies
| APD
| charles.moore@xxxxxxxxxxxxx
| (970) 288-4561
|--------------------------------------------------------------------|
jgoergen wrote:
Hi Charles
I get where you are going, but I am against removing the "improved fr-4" or
"enhanced fr-4" from any requirement.
My reasoning is that this implies all the channels we evaluate and the
standard we create are intended to run across fr-4 ... Which isn't true from
my point of view.
Take care
-joel
On 2/23/11 9:44 AM, "Charles Moore" <charles.moore@xxxxxxxxxxxxx> wrote:
paul,
I looked at the objectives for 802.3ba and kind of liked the wording
there. Cribbing from it, how about:
Provide Physical Layer specifications which support 4-lane 100 Gb/s
operation over:
* at least Xm over a copper cable assembly
* at least Ym over a backplane
This sidesteps the issue of defining "improver FR4", something which we
carefully avoided defining in 802.3ap. If we do use the term "improved
FR4", the actual definition will only come after we write a channel
spec. Then "improved FR4" is defined as any fire retardant material
which will allow you to build a compliant channel Ym long.
charles
|--------------------------------------------------------------------|
| Charles Moore
| Avago Technologies
| APD
| charles.moore@xxxxxxxxxxxxx
| (970) 288-4561
|--------------------------------------------------------------------|
Kolesar, Paul wrote:
John,
Thanks for posting your planned co-authored contribution on
objectives. As you said, this contribution proposes the form of the
objectives and leaves the key parameters open. I have previously
commented to this forum about a particular form that, while apparently
approved in the past, is illogical, conflicting and ambiguous because
it mixes words that define minima with words that define maxima.
Specifically, slide 4 states the reach requirements using the phrase
³up to at least X m². One can take this to define a maximum of X m
(i.e. ²up to²) or a minimum of X m (i.e. ³at least²). Given this
conflict the only logical interpretation that can simultaneously meet
both is a reach of _exactly_ X m. I do not find this acceptable and
have previously proposed to state these objectives clearly as minima
using the non-conflicting phrase ³of at least X m². This will avoid
some problems that have occurred in the past with interpretation when
the value of X was challenged.
I also do not understand the utility of the phrase ³consistent with².
It appears to be a way to interject some flexibility. But I do not
have an appreciation for what that implies. Perhaps someone could
enlighten me. Without that insight I would further simplify the form
to the following.
Define a 4-lane 100 Gb/s PHY for operation over copper traces on
³improved FR-4² for link lengths of at least ³X² m.
Define a 4-lane 100 Gb/s PHY for operation over copper twin-axial
cables for link lengths of at least ³Y² m.
Regards,
Paul Kolesar
------------------------------------------------------------------------
*From:* John D'Ambrosia [mailto:jdambrosia@xxxxxxxxxxxxxxx]
*Sent:* Wednesday, February 23, 2011 2:07 AM
*To:* STDS-802-3-100GCU@xxxxxxxxxxxxxxxxx
*Subject:* [802.3_100GCU] WebPage Updates
All,
This email is to inform you of two updates to the Study Group Web Pages.
First, Mark Bugg has provided a calibration file, which will allow
de-embedding of the board traces. This file may be found at
http://www.ieee802.org/3/100GCU/public/ChannelData/Molex_11_0210/2XCAL.zip.
My thanks to Mark for providing this file.
Next, as discussed at our prior meeting, the SG needs to focus on
setting its objectives. To that end I have worked with Howard Frazier
and Adam Healey on a presentation (see
http://www.ieee802.org/3/100GCU/public/mar11/dambrosia_01_0311.pdf) to
discuss objectives for the project. We have proposed the forms of
several objectives (leaving the important details as TBDs). I would
ask that everyone review this presentation, and consider how the
presentation that they plan to submit will contribute to helping us
determine our objectives. This presentation is only intended as an
initial list of key objectives.
Regards,
John