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Re: [802.3_100GNGOPTX] SMF and MMF Ad Hoc meetings: MMF objective



Hi Paul,

I understand you argument. As a user, I think we should be looking into this from another perspective.

What you are trying to do is to optimize the cost of the entire 100 GbE (worldwide). This looks to me like one size fits all. Many people are interested in optimizing the cost for their own company and applications. If we offer them two choices (let say for the sake of the argument one SMF,  2km and another MMF at 100 m), many of them would feel there is only one choice, unless you are in mega data center.

I am not sure that sizeable part of the MMF community should subsidize the cost for few, which happens when you look at the worldwide 100 GbE population. So, we need to consider what granularity in solutions is acceptable. I do not think I have seen that analysis.

I think the users should speak up on this. As a user, I strongly believe that there is merit for two PMDs for MMF. The longer reach MMF PMD can address the needs of some of the population you are interested in, without worrying about the cost or power consumption that much, yet will be competitive with SMF.
 
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:        "Kolesar, Paul" <PKOLESAR@xxxxxxxxxxxxx>
To:        STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Date:        02/24/2012 10:18 AM
Subject:        Re: [802.3_100GNGOPTX] SMF and MMF Ad Hoc meetings: MMF objective




Hi Steve,
Your response illustrates my point if one examines the cost situation a bit closer.  It is not sufficient to take a broad brush view that the SM optics will retain a step function cost increase relative to MM optics, because the magnitude of that step is critically important.  As I tried to show in my contribution at the last meeting in Newport Beach, the optimal reach objective for MM changes as a function of that step size.  When that SM step is about 5x there is parity in total cost (i.e. cost of all optics plus cost of all cabling needed to build data center switch-to-switch channels) between MM optics with a capability of 100 m and MM optics with a capability of 150 m.  In other words we could choose either a 100 m objective or a 150 m objective and get nearly the same total cost outcome.  If that step is larger than 5x, then a MM reach longer than 100 m is needed.  If that step is less than 5x then a MM reach of 100 m is optimal.  
 
To me it not a question of if the SM cost step will be reduced to 5x from its current magnitude, for all prior Ethernet SM solutions have seen this occur.  It is a question of when.  If the answer to “when” is projected to be so far into the future that LR4 remains a hindrance to broad market potential during the time when the market is projected to broaden, then that indicates we either need another SM PMD with cost structures that can remove that hindrance, or we need a MM objective that covers a greater portion of the longer length channels than can be addressed with a 100 m solution.  
 
So for me its all about understanding the various SM solution cost projections over time.  Give me that information and I can make a sufficiently informed determination on the optimal MM reach objective.
 
Regards,
Paul
 



From: Trowbridge, Stephen J (Steve) [mailto:steve.trowbridge@xxxxxxxxxxxxxxxxxx]
Sent:
Friday, February 24, 2012 8:14 AM
To:
Kolesar, Paul; STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject:
RE: [802.3_100GNGOPTX] SMF and MMF Ad Hoc meetings: MMF objective

 
Hi Paul,
I don’t think it is nearly so clear that you should decide SM first.
 
If there existed a SM solution that was cost-competitive with a MM solution at some reach, it would be a game changer, and those developing MM solutions would surely like to know if the game will change before getting too far down the path. But most seem to believe that the game will not change, and even if it did, it is hard to prove because it is difficult to compare relative costs of dissimilar technologies.
 
Most still seem to believe (in spite of the interesting technology from Opnext) that there will be a significant step function from MM to SM that will keep people from wanting to use it in data centers. Furthermore, if you need a different cable type, for example, for a 70m link than you need for a 100m link, that creates its own kind of problem.
 
So if the game does not change, then SR4 needs to try to address most, if not all, of the reach currently addressed by SR10. If it turns out not to be technically or economically feasible to do that (e.g., if you could only get 60 or 70m out of the beast within reasonable cost, size and power), then if SM is to replace MM above that reach, it needs to get down to a cost to compete with an SR10 with a reverse gearbox. Even if SM does this, it isn’t clear they will get all of that market because of a likely reluctance to mix cable types in the data center – maybe they are happier to use SR10 with a reverse gearbox to reuse their existing cabling.
Regards,
Steve
 
From: Kolesar, Paul [mailto:PKOLESAR@xxxxxxxxxxxxx]
Sent:
Friday, February 24, 2012 6:49 AM
To:
STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject:
Re: [802.3_100GNGOPTX] SMF and MMF Ad Hoc meetings: MMF objective

 
Jonathan,
While I understand the desire to find a launching point for the discussion, this poll is approaching the problem in the wrong order because we need to know what the single-mode objective is first.  
 
A purpose of the Study Group is to set objectives that will allow us to establish cost-optimized 100GE.  One cannot logically pick cost-optimized MM objectives without first having framework around the SM optics that will be used to address channels with lengths that exceed the MM reach.  At this point, we have not even established if we will have a SM objective.  In other words, we don’t know if the existing LR4 will remain the only one, or if there will be another one added.  Only when the SM situation is established can we know the minimum capability that a new MM optic must fulfill to optimize cost.
 
I suggest that we first conduct such a poll for SM and use it to start the objective discussion in the SM ad-hoc.  If that produces solid results, then undertake the same endeavor for MM.
 
 
Regards,
Paul
 



From: Jonathan King [mailto:jonathan.king@xxxxxxxxxxx]
Sent:
Thursday, February 23, 2012 8:13 PM
To:
STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject:
Re: [802.3_100GNGOPTX] SMF and MMF Ad Hoc meetings: MMF objective
Importance:
High

 
Dear all,
On the Feb 14th MMF ad hoc call , it seemed like we were  beginning to converge on a possible objective for MMF .
In the next meeting (Tuesday 28th Feb), I’d like to see if we can finalize a strawman MMF objective.  To that end I’ll prepare  a presentation which we can review  during the call which will include a strawman objective for review on the call, together with an overview of how it addresses the 5 criteria – to help get the best starting point for that discussion I’d like to get your responses to the questions below  questions:
 
The strawman objective will follow the wording in Anslow_01_0111
 
Define a 4-lane 100 Gb/s PHY for operation over OMX MMF with lengths up to at least Y m
 
 
1)      A reasonable MMF reach objective (i.e. the value of Y) would be
a.      100m
b.      Significantly less than 100m (what reach?)
c.       Significantly more than 100m  (what reach ?)
d.      decided in the task force
 
2)      The MMF type should be
a.      decided in the task force
b.      OM3
c.       OM4
d.      at least as good as OM4
 
Please send your responses to me directly at:  jonathan.king@xxxxxxxxxxx
I will collate and report the results but will not reveal any individual’s responses.
If you feel uncomfortable expressing an opinion, say so and I’ll note that.
 
To  repeat, this is not a formal poll or vote, just intended to give us the best starting point for discussion on Tuesday.
Please send your responses as soon as possible, and at least by close of business on Monday 27th Feb, 2012
Many thanks !
 
Jonathan King
MMF ad hoc chair, Next Gen 100G Optics
 
From: Anslow, Peter [mailto:panslow@xxxxxxxxx]
Sent:
Wednesday, February 22, 2012 2:10 AM
To:
STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject:
[802.3_100GNGOPTX] SMF Ad Hoc and MMF Ad Hoc meetings

 
Hi,
 
Following on from the meetings on 14 February, Jonathan and I are planning to hold an SMF Ad Hoc meeting immediately followed by an MMF Ad Hoc meeting (1 hour each) starting at 8:00 am Pacific on Tuesday 28 February.
 
If you would like to present a contribution at the SMF ad hoc, please send it to me and for the MMF ad hoc, send it to Jonathan.
 
Peter Anslow from Ciena has invited you to join a meeting on the Web, using WebEx. Please join the meeting 5-10 minutes early so we may begin on time.

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Topic: "SMF Ad Hoc followed by MMF Ad Hoc"

Date & Time: Tuesday, 28 February 2012 at 16:00, GMT Time (London, GMT)

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