Frank,
With all due respect I
cannot say that I have observed the trend you are speaking of. In fact, several
of my own customers have dropped EDC and moved toward simpler limiting type
ports. There are also simpler linear solutions getting traction that do the job
for everything except LRM reaches.
I also would be
interested in understanding what is implied by minimum extra power consumption.
A simple survey of available IC’s shows ~ 200 mW (absolute best case, comparing
0.065 um apples with 0.13 um oranges, otherwise a fair comparison is probably
400 mW) per SFP+ channel extra for chips with EDC, compared to chips without.
200 mW per port for a 48 port switch is close to 10 Watt. And you will have more
than one pizza box in a datacenter, I am sure.
Now that’s assuming LRM
type EDC, so with a light version that supposedly we can now do with I know you
guys are saying it won’t be as much, but then the burden is on you folks to
demonstrate this. Because otherwise the concept ingrained in a lot of folks
minds, including myself is EDC = lots of
power
I do agree with Ali
though, to have several interfaces, one XFI-like, and some SFI and KR like ones
as well for other PMDs.
Best
Gourgen
Oganessyan
Strategic Marketing
Manager
Quellan
Inc.
Phone: (408)-625-2196
(voicemail)
(630)-802-0574
(cell)
Fax: (630)-364-5724
e-mail:
gourgen@quellan.com
From: Frank
Chang [mailto:ychang@VITESSE.COM]
Sent: Friday, March 14, 2008 10:44
PM
To:
STDS-802-3-HSSG@LISTSERV.IEEE.ORG
Subject: Re: [802.3BA] Longer OM3 Reach
Objective
Petar;
I donot disagree with
your viewpoint, but my thinking this argument is really an application
call to the industry.
If you hint that
the significant more power is brought up by required EDC circuit, then
I disagree with that. As we know from various mtg discussions, we are
not talking about the complicate circuitry such as the one for LRM, which seems
unnecessarily overkill for such case. It should be very simple type of
equalization circuit, its extra power consumption could still remain
minimum, while could be well compensated by extra perf.
margin, much better yield, in addition to the flexibility and
simplicity in system adjustment because of implementing
it.
Also I donot
think we are in a position trying to avoid the use of EDC. The
trend shows that it could possibly become one standard feature in
PHY IC offering. Take the SFP+ as an example, even the SR version is
taking its advantage for extra margin, system robustness, less BOM etc
etc. This could be beyond the question regarding the incremental power
& complexity/cost related to that.
From: Petar
Pepeljugoski [mailto:petarp@us.ibm.com]
Sent: Friday, March 14, 2008 7:20
PM
To: Frank Chang
Cc:
STDS-802-3-HSSG@listserv.ieee.org
Subject: Re: [802.3BA] Longer OM3 Reach
Objective
Frank,
You are missing my point. Even
the best case stat, no matter how you twist it in your favor, is based on
distances from yesterday. New servers are much smaller, require shorter
interconnect distances. I wish you could come to see the room where current #8
on the top500 list of supercomputers is (Rpeak 114 GFlops), maybe you'll
understand then.
Instead of trying to design
something that uses more power and goes unnecessarilly longer distances, we
should focus our effort towards designing energy efficient, small footprint,
cost effective modules.
Regards,
Petar Pepeljugoski
IBM
Research
P.O.Box
218 (mail)
1101
Kitchawan Road, Rte. 134 (shipping)
Yorktown Heights, NY 10598
e-mail:
petarp@us.ibm.com
phone: (914)-945-3761
fax:
(914)-945-4134
|
Frank
Chang <ychang@VITESSE.COM>
03/14/2008 09:23
PM
|
Please respond
to
Frank Chang
<ychang@VITESSE.COM> |
|
|
To |
STDS-802-3-HSSG@LISTSERV.IEEE.ORG
|
|
cc |
|
|
Subject |
Re: [802.3BA]
Longer OM3 Reach
Objective |
|
Petar;
Depending on the
sources of link statistics, 100m OM3 reach objective actually covers from 70% to
90% of the links, so we are talking about that 100m isnot even close to 95%
coverage.
Regards
Frank
From: Petar
Pepeljugoski [mailto:petarp@US.IBM.COM]
Sent: Friday, March 14, 2008 5:09
PM
To:
STDS-802-3-HSSG@listserv.ieee.org
Subject: Re: [802.3BA] Longer OM3 Reach
Objective
Hello
Jonathan,
While I am sympathetic with
your view of the objectives, I disagree and oppose changing the current reach
objective of 100m over OM3 fiber.
From my
previous standards experience, I believe that all the difficulties arise in the
last 0.5 dB or 1dB of the power budget (as well as jitter budget). It is
worthwhile to ask module vendors how much would their yield improve if they are
given 0.5 or 1 dB. It is responsible for most yield hits, making products much
more expensive.
I believe that selecting specifications that penalize 95% of
the customers to benefit 5% is a wrong design point.
You make another point -
that larger data centers have higher bandwidth needs. While it is true that the
bandwidth needs increase, you fail to mention is that the distance needs today
are less than on previous server generations, since the processing power today
is much more densely packed than before.
I believe that
100m is more than sufficient to address our customers' needs.
Sincerely.
Petar
Pepeljugoski
IBM Research
P.O.Box 218 (mail)
1101 Kitchawan Road,
Rte. 134 (shipping)
Yorktown
Heights, NY 10598
e-mail:
petarp@us.ibm.com
phone: (914)-945-3761
fax:
(914)-945-4134
|
Jonathan
Jew <jew@j-and-m.com>
03/14/2008 01:32
PM
|
Please respond
to
jew@j-and-m.com |
|
|
To |
STDS-802-3-HSSG@LISTSERV.IEEE.ORG
|
|
cc |
|
|
Subject |
[802.3BA] Longer
OM3 Reach Objective |
|
I am a consultant with
over 25 years experience in data center
infrastructure design and data center relocations including
in excess of 50
data centers
totaling 2 million+ sq ft. I am currently engaged in
data
center projects for one of the
two top credit card processing firms and one
of the two top computer
manufacturers.
I'm concerned
about the 100m OM3 reach objective, as it does not cover
an
adequate number (>95%) of
backbone (access-to-distribution and
distribution-to-core switch) channels for most of my clients'
data centers.
Based on a review of my current and past projects, I expect
that a 150m or
larger reach
objective would be more suitable. It appears that some of
the
data presented by others to the
task force, such as Alan Flatman's Data
Centre Link Survey supports my
impression.
There is a pretty
strong correlation between the size of my clients' data
centers and the early adoption of new technologies such as
higher speed LAN
connectivity.
It also stands to reason that larger data centers
have
higher bandwidth needs,
particularly at the network core.
I strongly encourage you to consider a longer OM3 reach
objective than 100m.
Jonathan
Jew
President
J&M
Consultants, Inc
jew@j-and-m.com
co-chair BICSI data center standards
committee
vice-chair TIA TR-42.6
telecom administration subcommittee
vice-chair TIA TR-42.1.1 data center working group (during
development of
TIA-942)
USTAG
representative to ISO/IEC JTC 1 SC25 WG3 data center standard
adhoc