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Re: [802.3BA] XR ad hoc Phone Conference Notice

Steve,
 
I agree that the objective states "at least 100m on OM3 MMF", but the question is what is the cost point for exceeding the 100m?  Can you provide data that shows the relative cost between 10 parallel MMFs vs. 1 SMF running 2-400m?
 
There was also another reason that 100m was seen as a good reach.  At these data rates, it may take a long time for a UTP or any twisted-pair solution to satisfy the typical 100m data center reach.  Failure to provide a cost effective solution for that market has a direct impact to the broad market potential.
 
Cheers,
Brad

From: Swanson, Steven E [mailto:SwansonSE@xxxxxxxxxxx]
Sent: Thursday, July 10, 2008 7:30 AM
To: Brad Booth; STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3BA] XR ad hoc Phone Conference Notice

Brad,
 
Just to be crystal clear, the objective reads:
 

"at least 100m on OM3 MMF"

While I agree that 100m meets that objective, Kolesar and I presented data in November 2006 noting that 100m was not adequate. We were assured that longer link lengths could be accommodated because of the words "at least." This was my beef in Munich.

In a survey of our customers 0/20 said that 100m was adequate and that MMF was preferred over SMF where possible.

I still don't understand why it is OK to have two link length objectives for SMF (and we considered a third (2-4km)) but we can't have two link length objectives for MMF. Better yet from my point of view is to have one PMD that satisfies both - the premium that we are talking about at the module level (estimated at ~20%) is in the noise for 40/100.

We need a compromise here of some sorts.

Steve


From: Brad Booth [mailto:bbooth@xxxxxxxx]
Sent: Wednesday, July 09, 2008 11:11 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice

That's an excellent point.  I'm glad that Jeff brought this up.
 
The objectives state 100m on OM3.  That is the requirement of the project and one by which the draft standard will be judged.  There is no requirement to satisfy a non-objective.
 
Thanks,
Brad
 

Brad Booth
Sr. Principal Engineer, AMCC
bbooth@xxxxxxxx

From: Petar Pepeljugoski [mailto:petarp@xxxxxxxxxx]
Sent: Wednesday, July 09, 2008 9:51 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice


Frank,

If I interpret correctly, you are saying that all users should amortize the cost of very few who need extended reach.
We need to be careful how we proceed here - we should not repeat the mistakes of the past if we want successful standard.

Regards,

Peter

Petar Pepeljugoski
IBM Research
P.O.Box 218 (mail)
1101 Kitchawan Road, Rte. 134 (shipping)
Yorktown Heights, NY 10598

e-mail: petarp@xxxxxxxxxx
phone: (914)-945-3761
fax:        (914)-945-4134



From: Frank Chang <ychang@xxxxxxxxxxx>
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Date: 07/09/2008 10:29 PM
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice




Hi Jeff;
 
Thanks for your comment. You missed one critical point that there is cost increase from OM3 to OM4. If you take ribbon cable cost in perspective, OM4 option is possibly the largest of the 4 options.
 
Besides, the use of OM4 requires to tighten TX specs which impact TX yield, so you are actually compromising the primary goal.
 
Frank
From: Jeff Maki [mailto:jmaki@xxxxxxxxxxx]
Sent: Wednesday, July 09, 2008 7:02 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice

Dear MMF XR Ad Hoc Committee Members,
 
I believe our current objective of “at least 100 meters on OM3 MMF” should remain as a primary goal, the baseline.  Support for any form of extended reach should be considered only if it does not compromise this primary goal.  A single PMD for all reach objectives is indeed a good starting premise; however, it should not be paramount.  In the following lists are factors, enhancements, or approaches I would like to put forward as acceptable and not acceptable for obtaining extended reach.
 
Not Acceptable:
1. Cost increase for the baseline PMD (optic) in order to obtain greater than 100-meter reach
2. EDC on the system/host board in any case
3. CDR on the system/host board as part of the baseline solution
4. EDC in the baseline PMD (optic)
5. CDR in the baseline PMD (optic)
 
Acceptable:
1. Use of OM4 fiber
2. Process maturity that yields longer reach with no cost increase
 
In summary, we should not burden the baseline solution with cost increases to meet the needs of an extended-reach solution.
 
Sincerely,
 
Jeffery Maki
 
 
————————————————
Jeffery J. Maki, Ph.D.
Principal Optical Engineer
Juniper Networks, Inc.
1194 North Mathilda Avenue
Sunnyvale, CA  94089-1206
Voice +1-408-936-8575
FAX +1-408-936-3025
www.juniper.net
jmaki@xxxxxxxxxxx
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