I agree that ribbon costs make it a poor
choice for >100m.
I’m not sure that I see much of
clear advantage for MMF for <100m especially if it is ribbons of MMF; if
compared to a Short-Distance WDM-SMF solution. It might be different if it was
a simple pair of MMF for <100m.
It would seem to me that UNLESS the
transceiver costs for Short distance WDM-SMF is problematic, that could work for
all distances <100m and >100m (within the Enterprise).
Given that the technologies and the relative
economics of the technologies required to implement Higher-Speed Ethernet
Optical Transceivers may not quite as obvious as it was for 10G, it may be best
for Optical Vendors to make proposals for the Optical PMDs regarding what they
perceive as being feasible and cost-effective.
From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxx]
Sent: Tuesday, August 22, 2006
3:13 PM
To: Roger Merel; Traverso, Matt
Cc:
STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] Reach
Objectives
Roger and Mat
Generally in the data center it is more desirable to use multi-mode fiber for
ease of use, handling, and termination.
I prefer to make the ribbon fiber MMF and use CWDM on SMF. Because of the
ribbon cable cost I don't see
a reason to define length beyond the datacenter (100 m) or define an SMF ribbon
PMD.
Thanks,
Ali
Roger Merel wrote:
Agree
with Matt that once you are considering a new cable (ribbon MMF), the
considerations are different, and SMF make the distinction between
50m/100m/300m/2km irrelevant. One PMD should address all of them.
However, the optimal solution may not be
parallel SMF fibers but rather multiple-lambdas over a single-pair of
SMF. In which case you don’t have to suffer the cost of ribbon
fiber (of either SMF or OM3) which can be less economically attractive both
“per meter” and “per patch panel”.
-Roger
Hi Petar, John,
Since the OM3 fiber we are discussing would primarily be parallel, is there
merit in defining an OM3 PMD versus specifying a parallel SMF based
PMD?
My assumption is that in both cases the data center in question would be
pulling new fiber. If my assumption is true, then we should not limit our
consideration to OM3,but should also look at SMF. For example SMF would
allow for the extension to greater distances more simply.
There may indeed be merit in defining the data center PMD to be OM3 based, but
my opinion is that we should not jump to conclusions.
thanks
--Matt Traverso
Opnext, Inc.
mtraverso@xxxxxxxxxx
Note - I sent this from a personal account to avoid an automated statement from
my IT dept which contains phrases that would likely be considered
"unfriendly" to the reflector.
On 8/22/06, Petar Pepeljugoski <petarp@xxxxxxxxxx> wrote:
Brad,
I
agree with you. And the breakpoints vary from solution to solution.
Let's
consider the following two examples:
1. N
ch. x 10 Gb/s over OM3 fiber at 50m, and at 100m, there is very little
difference in the specs, so the cost will most likely not be affected.
2. M
ch. x 17 Gb/s (or 20 gb/s) over OM3, there will be much larger difference
between 50m and 100m and there might be cost premium.
This
will depend on the expected yield distribution and how sensitive is to changes
in the specs. So, we will need to carefully tread and not become prisoners to
the reach objectives, but rather optimize the cost.
From
our perspective, there are distances up to 150m, but the largest distances are
not so common, so that is why I proposed the 100m.
Whatever
is not covered by the 0-100m, should be covered by the next PMD (most likely
SMF based). That will reduce the cost by giving it additional volume, while the
short distance on the MMF will drive the cost by increasing the yield.
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
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Re: [HSSG] Reach Objectives
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Excuse my ignorance, but why? When 10G
started, this was an important debate. If they had stuck with the number
of PMDs in 802.3z, then there would have only been two PMDs. The study group
needs to define the markets that it wants to satisfy, and only then when the
study group becomes a task force can the group decide on the actual number of
PMDs required.
Thanks,
Brad
From: Drew
Perkins [mailto:dperkins@xxxxxxxxxxxx]
Sent: Tuesday, August 22, 2006 10:45 AM
To: Brad Booth; STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: RE: [HSSG] Reach Objectives
I have a simple proposal to save everyone a lot of time.
Let's make the baseline plan to stick with exactly the same number of PMDs with
exactly the same reaches as 10GbE. They have all been developed to fit
someone's requirements. We should have a very high hurdle to eliminate any of
these or add to them.
Drew
_____________________________
Drew Perkins
Chief Technology Officer
Infinera Corporation
1322 Bordeaux Drive
Sunnyvale, CA 94089
Phone: 408-572-5308
Cell: 408-666-1686
Fax: 408-904-4644
Email: dperkins@xxxxxxxxxxxx
WWW : http://www.infinera.com
_____________________________
From: Brad Booth
[mailto:bbooth@xxxxxxxxxxxxx]
Sent: Tuesday, August 22, 2006 10:19 AM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] Reach Objectives
The 10km vs. 2km debate occurred in 802.3ae. It was
determined that the solution for 2km was virtually the same as that for 10km;
therefore, the task force felt it would be better to select only one of those
reaches and 10km was it. If there is a desire for 2km and 10km reaches in
HSSG, then in my humble opinion, those wishing to support will need to bring
justification forward as to why the study group should consider possibly
increasing the number of PHYs.
Cheers,
Brad
From: Frank Chang
[mailto:ychang@xxxxxxxxxxx]
Sent: Tuesday, August 22, 2006 9:19 AM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] Reach Objectives
John/Petar;
I agree datacenter for up to 100m. How about 10GigE LR
disctance (10km) or campus 2km discussed earlier?
Frank
-----Original
Message-----
From: Petar Pepeljugoski [mailto:petarp@xxxxxxxxxx]
Sent: Tuesday, August 22, 2006 6:02 AM
To: STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: Re: [HSSG] Reach Objectives
John,
I believe that the Data Center
distances should be 100m and 300m.
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
All,
We have had some conversation on the reflector regarding reach objectives.
Summarizing what has been discussed on the reflector I see the following
–
Reach Objectives
Long-Haul --> 100+ km
Metro --> 10+ km
Data Center --> 50m & 300m
Data Center Reach Segregation
Intra-rack
Inter-rack
Horizontal runs
Vertical risers
Use this data to identify a single low-cost solution that would address a
couple of the reach objectives
Other Areas
During the course of the CFI there were individuals who wanted Backplane
Applications kept in for consideration, but I have not heard any further input
in this area. Are there still individuals who wish to propose Backplane
as an objective?
John
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