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Re: [802.3_100GCU] Successful May Interim



Hey Joel,
 
I guess we disagree on that point.
 
My concern has less to do with channel models and loss budgets. I'm more concerned with broad market potential. I understand that there is a basic trade-off between gauge and reach, and at 5m with 24 AWG I can see the market potential for the solution knowing that shorter reaches of twinax should be able to use narrower gauge wire.
 
If the TF decreases the wire gauge to meet the reach, then the TF can safely say they met the objective, yet it is highly unlikely that they will have any broad market potential. If the reach is reduced, then it will be harder to supply narrower gauge twinax for shorter cables.
 
There is a 100GBASE-CR10 solution and the WG is about to consider a 100GBASE-CR4 solution. Let's at least try not to repeat the 10GBASE-LX4 and -LRM mistakes.
 
Thanks,
Brad

On Tue, May 31, 2011 at 2:53 PM, Joel Goergen <jgoergen@xxxxxxxxx> wrote:
Hi Brad,

I understand what you are asking for ... But I firmly don’t believe it belongs in the objectives.  

As engineers, we want to solve the problems “this second” and hard wire everything into the objectives ... Including channel modes, regardless if they are copper cable, fiber cable, or copper circuit board.  Channel model discussions should be done at the working group.

Nothing in the objectives prevent the implementation on reasonable suggestions, for either copper back plane or copper cable.

You have Chris and Steve’s views already ... Just adding mine.

The objectives and the work done by all to get here is very thorough and solid ... I don’t agree with how we may deal out the cabling loss budget, but I will argue that case in working group and not in the objectives.  I will prove my points and make recommendations.  My view is that if you are worried about 24awg, then please bring your best forward in the working group and present the cabling models you feel should be included in the drafts.

Just my two cents ....

Take care
-joel


On 5/31/11 11:59 AM, "Brad Booth" <bjbooth@xxxxxxxxx> wrote:

Chris,
 
My concern is about the objective. There is no mention of AWG in the twinax reach objective, even though it is probably fair to assume most people based their decision on 24 AWG.
 
Study groups have usually spent time trying to be specific when it comes to the UTP and optical cabling in reference to the reach. In this case, it may be useful to state that the 5m reach is based upon 24 AWG, because while the industry complains about its bend radius, it may be deemed acceptable for that reach. If the TF was to adjust the reach based upon using 24 AWG or decrease the gauge, then different criteria come into play and comments/ballots can be submitted accordingly.
 
It has been stated repeatedly in previous SG meetings is that the objectives are a contract with the WG about the work to be performed by the TF. It may be in the SG's and WG's best interest to ensure that there is good agreement on the gauge being assumed for a 5m twinax reach.
 
Cheers,
Brad
 
 
On Tue, May 31, 2011 at 10:10 AM,  <CDimi80749@xxxxxxx> wrote:
Brad,
 
Please find responses inline....
 
Brad: If there is no information provided that indicates 24 AWG twinax copper cabling can meet the bend radius, diameter and weight requirements for inter-rack and intra-rack interconnect, then has the study group sufficiently responded to broad market potential?
 
Chris:
>>24 AWG twinaxial copper cables are used for inter-rack and intra-rack interconnects.
>>Although there are documents that address specifications for 24 AWG twinax copper interconnects related to bend radius, they don't constitute requirements for inter-rack and intra-rack interconnect applications.
>>For CX4, CR4 and CR10 the cable assembly differential characteristics are specified. During the development of these specifications, 24 AWG cable assembly measurements were presented.
>>In the formulation of the IEEE 802.3 100 Gb/s Backplane and Copper Study Group call for interest material, I provided outer dimensions for 24 AWG twinaxial cable - 9.3 mm (0.366).  
 
Regards, Chris
 
 
 
In a message dated 5/30/2011 10:50:28 P.M. Eastern Daylight Time, bjbooth@xxxxxxxxx writes:

John,

 
 
Glad to hear that the meeting was successful.
 
 
 
Was there any consideration for listing the gauge of the wire for the 5m  twinax copper cabling objective?
 
 
 
At the meeting in Singapore, there was a request during the straw poll to  list the gauge of wiring and it did slightly alter the results of the poll.  Even the presentation by Mark Gustlin at last week's meeting highlighted the  importance of bend radius and diameter which can be directly related to the  gauge of wire. Did the study group discuss the bend radius and  diameter requirements? Is it fair to assume that the gauge of wire for  the twinax copper cabling objective is the same used in the Singapore straw  poll (24 AWG)? If 24 AWG is assumed, was there any information presented or  provided to indicate that the cable would be able to meet the bend radius,  diameter and weight requirements for the intended application?
 
 
 
If there is no information provided that indicates 24 AWG twinax copper  cabling can meet the bend radius, diameter and weight requirements for  inter-rack and intra-rack interconnect, then has the study group sufficiently  responded to broad market potential?
 
 
 
Thanks,
Brad
 
 
 
 
 
 
 
On Sat, May 28, 2011 at 11:39 PM, John D'Ambrosia <jdambrosia@xxxxxxxxxxxxxxx>  wrote:
 

 
 

Dear Study Group Participants,
 
I hope everyone had safe journeys home.     I have to say it was one of my more adventurous travels.  However,  given the success of the meeting, the travel was well worth it! 
 
 
 
The Study Group was successful in reaching consensus on  the objectives, PAR, and 5 Criteria responses.  They have been posted,  and may be found at http://www.ieee802.org/3/100GCU/index.html.
 
 
 
July will be the next key milestone, as we look forward  to the necessary approvals to move from Study Group to Task Force. 
 
 
 
The minutes will be posted shortly.
 
 
 
Best Regards,
 
 
 
John D’Ambrosia
 
Chair, IEEE 802.3 100Gb/s Backplane and Study Group