Re: [802.3_100GCU] WebPage Updates
Does it makes sense to specify that 'improved FR4 ' needs to have Er & Df below/above this limit @ particular frequency to meet channel criteria.
Bhavesh Patel
-----Original Message-----
From: John D'Ambrosia [mailto:jdambrosia@xxxxxxxxxxxxxxx]
Sent: Thursday, February 24, 2011 2:57 PM
To: STDS-802-3-100GCU@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GCU] WebPage Updates
Charles,
IMHO I think it is appropriate to specify what we intend to run over in the objective, as well as then provide a definition of what that means.
John
-----Original Message-----
From: Charles Moore [mailto:charles.moore@xxxxxxxxxxxxx]
Sent: Thursday, February 24, 2011 3:53 PM
To: John D'Ambrosia
Cc: STDS-802-3-100GCU@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GCU] WebPage Updates
john,
My point is a very minor one and was made badly. Joel and i agree
that we do not want to imply that any FR-4 is going to work. I want to
get the point across by not using the term FR-4 at all, joel wants to
get the point across by putting "improved" in. I am a little concerned
that since the term was used in the ap objectives that it might be
construed to imply the amount of improvement to make ap work.
It is really a matter of communication and which words express the
right idea to the largest number of people. If a straw pole says
"improved FR-4" i will be happy to go along.
charles
|--------------------------------------------------------------------|
| Charles Moore
| Avago Technologies
| APD
| charles.moore@xxxxxxxxxxxxx
| (970) 288-4561
|--------------------------------------------------------------------|
John D'Ambrosia wrote:
> 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
>>>>
>>>>
>>>>
>>
>>