Re: [802.3BA] XR ad hoc Phone Conference Notice
Alessandro,
I'd like to continue your thread with
some observations that have driven me to certain conclusions, and to follow
that with a suggestion about how to parse the approach and drive to a consensus
position.
First let's consider what various customers
are telling us. The Corning survey of their customers, which has
been presented to the Ethernet Alliance, the XR ad-hoc, and will be presented
next week to 802.3ba, shows that the large majority of customers want a
single PMD solution that can provide 150m on OM3 and 250m on OM4. A
minority were willing to accept a two PMD solution set that delivers the
lowest cost PMD to serve up to 100 m and a second PMD to serve the extended
distances as above. Not a single response indicated a preference
for a solution limited to 100m. We also hear strongly expressed opinions
from various system vendors that a longer distance solution is not acceptable
if it raises cost or power consumption of the currently adopted 100m PMD.
Under these conditions, and given the options presented and debated
within the XR ad-hoc, I believe you are justified in concluding that a
single PMD cannot satisfy all these constraints. Yet it is clear
to me that the market will demand a low-cost PMD that can support more
than 100m to fulfill the distance needs of data centers. Therefore
I conclude that the correct compromise position is to develop a two-PMD
solution. If the committee does not undertake this development, it
is likely that several different proprietary solutions will be brought
to the market, with the net result of higher overall cost structures.
So let's consider how to choose from
among the various proposals for an extended reach PMD and let the determination
of how to document it within the standard be addressed after that.
I would propose a series of polls at
next week's meeting designed to gauge the preferences of the Task Force.
I do not think that any XR proposal will garner >75% at the outset,
so I would propose the use of Chicago rules wherein members may vote for
all the proposals they find acceptable. From this we can see which
of the solutions is least acceptable. Then through a process of elimination
from the bottom, and repeated application of Chicago rules for the remainder,
finally determine the most acceptable solution.
Depending on the degree of maturity
of the specifications or other considerations for the chosen solution,
the Task Force will be better able to determine how it should be handled
within the standard. For example, a proposal with a maturity on par
with the adopted baseline could be put forth under a new objective without
undue concern of becoming a drag on the timeline, while a proposal of lesser
maturity could be placed in an annex without an additional objective.
Regards,
Paul Kolesar
CommScope Inc.
Enterprise Solutions
1300 East Lookout Drive
Richardson, TX 75082
Phone: 972.792.3155
Fax: 972.792.3111
eMail: pkolesar@xxxxxxxxxxxxx
| "Alessandro Barbieri
(abarbier)" <abarbier@xxxxxxxxx>
07/10/2008 04:43 PM
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Please respond to
"Alessandro Barbieri (abarbier)" <abarbier@xxxxxxxxx> |
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Subject
| Re: [802.3BA] XR ad hoc Phone Conference
Notice |
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Matt,
here is my *personal* read of
the situation in the XR ad hoc:
a) I think there could be consensus
on supporting XR, as long as we pick a solution that does not impact the
cost structure of the 100m PMD. Because of that I also don't feel a single
PMD is realistic at this point.
a) The trouble however is that
there is no consensus (>75%) on any of the technical proposals. No one
proposal has a clear lead over the others.
Of the three options you list
below, I think adding an objective for a ribbon XR PMD could have a major
impact on the project schedule, because it seems we are nowhere near technical
consensus. We could drag the discussion for several TF meetings...I am
not sure delaying the project over this specific topic is worth it.
We can always resort to non-standard
solutions to fulfill market requirements we can't address within IEEE,
or come back in the future with another CFI.
At the end of the conference call
earlier today I requested that we get together after hours next week to
see if we can accelerate consensus building.
All the data is on the table now,
so if we don't show any material progress, I am not sure we should extend
this ad hoc.
Alessandro
From: Matt Traverso [mailto:matt.traverso@xxxxxxxxx]
Sent: Thursday, July 10, 2008 10:07 AM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3BA] XR ad hoc Phone Conference Notice
Colleagues,
I feel that we are coming to a situation similar to the impasse at 40G
vs. 100G where different participants call different segments of the networking
industry their customer.
For MMF, I'd like to see an optimized solution at 100m per all of the work
that has been done.
I'd like to understand if folks feel that a different status for the extended
reach
a) Informative
b) Normative
c) New objective
would significantly alter the technically proposed solution from the Ad
Hoc. Opinions?
Chris,
The case of slow market/industry transition from LX4 to LRM is one of the
reasons why I would like to see the industry adopt 40G serial from the
launch. The slow adoption of LRM has primarily been limited by end
customer knowledge of the solution. 40G serial technology is available.
thanks
--matt
Hi Gourgen,
Some numbers might help clarify
what close to 0 means.
For 2008, Lightcounting gives
a shipment number of approximately 30,000 for 10GE-LRM (and for 10GE-LX4
it's about 60,000.) So close to 0 would apply if we were rounding to the
nearest 100K. As an aside, 10GE-LRM supports 220m of MMF, not 300m.
300m of OM3 is supported by
10GE-SR, which Lightcounting gives as approximately 400,000 in 2008, so
that would be close to 0 if we rounding to the nearest 1M.
Another interesting sideline
in looking at these numbers is that 2 years after the 10GE-LRM standard
was adopted in 2006, despite the huge investment being made in 10GE-LRM
development, and despite very little new investment being made in 10GE-LX4,
the 10GE CWDM equivalent (i.e. 10GE-LX4, 4x3G) is chugging along at 2x
the volume of the 10GE Serial solution that was adopted to replace it.
This should put some dim on
hopes that very low cost 40GE Serial technology can be developed from scratch
in two years and ship in volume when the 40GE standard is adopted in 2010.
Chris
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
Petar,
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
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
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
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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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