How did this thread get started?
I do not understand the point of comparing
a PHYless MSA with a copper PHY. From a systems perspective, if you are
going to compare power budgets, you need to count all the ICs that make the
connection work, not just the optical PMD.
If you want the lowest power, plug a
copper cable into an SFI interface.
Bruce
Bruce Tolley
Vice President, Marketing
Solarflare Communications
9501 Jeronimo Road,Suite 250
Irvine, California 92618
ip phone 949 581 6830 X2014
mobile 650 862 1074
btolley@solarflare.com
From: Schube, Scott A
[mailto:scott.a.schube@INTEL.COM]
Sent: Tuesday, April 10, 2007 4:03
PM
To:
STDS-802-3-HSSG@listserv.ieee.org
Subject: Re: [HSSG] 40G MAC Rate
Discussion
To add to Paul’s comments I’ll
put some actual power dissipation numbers next to this for perspective. I
believe existing 10GBASE-T solutions are in the neighborhood of 10 W, with
newer implementations going down to 5-6 W. Someone from the 10GBASE-T
community can correct me if I’ve got it wrong, as I’m not an expert
in this area. So moving to ~25W in the near future for 4 10GBASE-T
ports. This is compared with a 40G QSFP at 3.5W or 4 SFP+ modules at 1W
apiece.
So at least for the next couple of years,
the big factor in power dissipation for a 4x10G LAG vs. 40G solution would
likely be whether it’s done in copper or fiber, not whether it’s a
4x10 LAG or 40G solution. Where the power dissipation numbers go from
there, like Paul said, depends on a lot of factors and is up for (no doubt
spirited) debate.
Scott
>>Scott Schube
>>Strategic Marketing Manager
>>Intel Optical Platform Division
>>(510) 578-5815
>>scott.a.schube@intel.com
From: Paul Kolesar
[mailto:PKOLESAR@SYSTIMAX.COM]
Sent: Tuesday, April 10, 2007 3:45
PM
To:
STDS-802-3-HSSG@listserv.ieee.org
Subject: Re: [HSSG] 40G MAC Rate
Discussion
First, let me apologize for misspelling Scott Kipp's last name in my
previous note. Sorry Scott.
Mikael,
I
think you have touched on the key issue facing 10GBASE-T: power dissipation.
While we can look forward to lower power consumption with future IC
feature reductions, these will be muted by the need for multiple 10GBASE-T PMDs
in a LAG or other parallel scenario. Such power reductions will also
enable lower power consumption by the optical PMDs, although by relatively
smaller power reduction ratios. In my estimation it will be difficult, or
far into the future, to deliver a 4x 10GBASE-T device that dissipates the
equivalent dissipation of 40G parallel optical transceivers.
The
cost of the copper cabling will also be 4x higher than for a single 10GBASE-T
link. So here it would loose its most of its competitive edge.
The
relative PMD cost factors are unknown, since I am not aware of 10GBASE-T ports
in the market at this time. But it is very likely that once 10GBASE-T become
highly integrated, they will compete with the parallel optical transceivers
where their application spaces overlap. It is unclear if that overlap
will include 40G applications, since LAG deployments will fade as the single
PMD solutions become available.
Time
appears to be one of the variables with the greatest influence on the optimal
choice. Will that play best to copper or fiber? Somebody with a
better crystal ball than mine on the issues outlined above needs to weigh in.
Regards,
Paul Kolesar
CommScope Inc.
Enterprise® Solutions
1300 East Lookout Drive
Richardson, TX 75082
Phone: 972.792.3155
Fax: 972.792.3111
eMail: pkolesar@commscope.com
|
Mikael Abrahamsson
<swmike@SWM.PP.SE>
04/10/2007
03:04 PM
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Please respond
to
Mikael Abrahamsson <swmike@SWM.PP.SE>
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To
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STDS-802-3-HSSG@listserv.ieee.org
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cc
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Subject
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Re: [HSSG] 40G MAC Rate Discussion
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On
Tue, 10 Apr 2007, Ali Ghiasi wrote:
> I know there is readily available solution based
on QSFP that could do
> 40G copper with twin-ax cables. Copper
solution are very attractive for
> sub-10m as they offer order of magnitude cost
advantage. Longer reach
> cable not as attractive as you have to use
heavier gage which increase
> the cable size, weight, cost, and the
complexity of receiver increases.
Well, my idea was to compare 4*10GE LAG and
whatever 40GE solution is
being proposed. I understand now I should have
written this outright,
sorry.
My thoughts were that operational cost and CAPEX
of doing 4*10GE LAG using
10GBASE-T for servers would be quite a lot lower
than any new proposed
40GE solution, since I only saw coaxial and fiber
proposed for 40GE
physical media.
Or have I misunderstood 10GBASE-T when it comes to
power and reach (100M
over CAT7 or ~50 on CAT6)? Does it require a lot
more power than fiber
based solution?
From a pure end-user perspective CAT6-7 based
cabling has the lowest
operational cost (physical only) since it's
abundant and there is a lot of
experience with that kind of cabling. But perhaps
it uses a lot more power
than the other proposed solutions for 40GE?
--
Mikael Abrahamsson email:
swmike@swm.pp.se