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

Hello Gary


The question, ‘will a signal conditioner be always needed?’, I believe has been answered negatively.  That’s clear to me both from the support I see for the baseline proposal and direct connection to the host IC as well as the shift from Xenpak to XFPs to SFP+.  I don’t disagree that for those whose systems will always need signal conditioners, a more integrated solution will be beneficial.






From: Gary Nicholl (gnicholl) [mailto:gnicholl@xxxxxxxxx]
Sent: Thursday, July 10, 2008 5:05 AM
To: PETRILLA,JOHN; STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3BA] XR ad hoc Phone Conference Notice




If it turns out that a signal conditioner will always be needed and a direct attach between the host IC and the pluggable module cannot be supported (at least for the many situations you mention below), then I think the signal conditioner should be integrated into the pluggable optical module (and ideally into the existing Tx and Rx ICs in the module as Ryan as suggested in the past).


This would provide the lowest overall system power (and especially if the SC is integrated into existing ICs in the module). It also means that we would have one less electrical interface to deal with, as the PMD service interface would now be an internal module interface completely under the control of the individual module vendors and there would be no need to specify it  within 802.3ba (which would save us all alot of work).






From: PETRILLA,JOHN [mailto:john.petrilla@xxxxxxxxxxxxx]
Sent: Wednesday, July 09, 2008 11:40 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice



Perhaps, I can point this out before Ryan.  It seems to me that many pcb layouts will present sufficient challenges such that a direct connection between the host IC and pluggable module will not be supported and a signal conditioner will be needed between the host IC and module.  This means that for reasons other than extending the optical link reach, the means to extend the optical link reach are in place at least for these situations.  All that is needed then is a way to permit the installer to take advantage of the optical link extension that an external signal conditioner, adjacent to but not included in the module, provides.  It will be frustrating to have all the pieces paid for and in place and not be able to take advantage of the extended link reach that they offer.


By the way, a similar situation exists with respect to using FEC.






From: Gourgen Oganessyan [mailto:gourgen@xxxxxxxxxxx]
Sent: Wednesday, July 09, 2008 8:02 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice



Well, sadly that’s what has been happening in the 10G world, people are forced to amortize the cost of 300m reach (LRM), while in reality the number of people who need 300m is close to 0.

That’s why I am strongly in support of your approach of keeping the 100m objective as primary goal.


Frank, OM4 can add as much cost as it wants to, the beauty is the added cost goes directly where it’s needed, which is the longer links. Alternatives force higher cost/higher power consumption on all ports regardless of whether it’s needed there or not.


Gourgen Oganessyan


Quellan Inc.

Phone: (630)-802-0574 (cell)

Fax:     (630)-364-5724

e-mail: gourgen@xxxxxxxxxxx

From: Petar Pepeljugoski [mailto:petarp@xxxxxxxxxx]
Sent: Wednesday, July 09, 2008 7:51 PM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice



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.



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


Frank Chang <ychang@xxxxxxxxxxx>




07/09/2008 10:29 PM


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.

From: Jeff Maki [mailto:jmaki@xxxxxxxxxxx]
Wednesday, July 09, 2008 7:02 PM
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)
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.
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