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Hey Ali,
I
think we are now in agreement. Only difference is the assumption on 1st
gen opticals. My point being that why do a 10 lambda version rather than a
4 lambda version right away. A 4 lambda solution is better aligned to
taking advantage to the technology curve on both the optical and electrical
technology. I agree that an inverse electrical mux isn't very
attractive.
My sense is that this is the conclusion that many are coming to as
well. However that is a decision for later in the
process. But this transition aspect is key to the decision in my
opinion.
Mark
Mark
I guess we are not in full agreement!
I do agree
early solution will be based on 10x10G, CTBI helps with Gen 1 and Gen
1.5.
Just as we transition from X2 to XFP/SFP+, 100Gig Gen2 will use
25Gig for the module interface.
Which mean just as in case of XFP/SFP+
module if you want to support LX4 or CX4 you need to
put a reverse Mux in
the module!
As you know there is no compatibility between LX4
and LRM which both serve the same market. I expect as
the technology
clock moves forward the module interface probably will be 4 lanes with 4
Lambdas and less, you are proposing
for sake of compatibility with a Gen 1
the line interface should be 10 Lambdas. This means using awkward
reverse mux module.
We should not limit the future volume drivers
for sake of Gen 1 product as we did with 10Gig
E.
Thanks,
Ali
Mark Nowell (mnowell) wrote:
Ali,
I don't think we are saying the same thing but maybe we are not
being specific enough.
I feel that the versions of the optical interface should be kept to a
minimum (one per reach) to ensure interop. So we pick a number
of wavelengths and then see evolution on the technologies from eml to dml as
technology matures. The user has no interop issues. This is what
we saw happen at 10GE LR.
I think we agree that the electrical interface will start at 10Gx10
and when that technology matures it may also move to a narrower faster
interface. We saw this with XAUI to XFI and it is an implementation
decision which did not affect user interop. XFP LR interops with
XENPAK LR.
I see the electrical and optical interfaces as decoupled. One
is an implemenation issue, the other is a interoperation
issue.
For what it is worth, one goal of the CTBI proposal was to simplify
these transitions.
Mark
Mark
You
might have misunderstood me. I was trying to say the early implementation
would be based on 10x10 with 10 Lamda,
followed by 4x25G with 4
lamda. I expect when you are using 4x25G then you will use 1310 nm
for 10Km and 1550 nm for
40Km. It is natural on the early
implementation based on 10x10 to use 1310 nm for 10Km and 1550 nm for 40
Km.
I believe we are saying the same
thing!
Thanks,
Ali
Mark Nowell (mnowell) wrote:
Ali,
I'm not sure I share your opinion that the early implementations
will be different from the later implementations in terms of
wavelengths. From a user perspective, this creates a big
interoperability challenge. The development effort to do a single
implementation is not something you want to throw
away.
If you had said, early implementations may differ in terms of
technology (eg ML going to DML) then I would agree. This raises no
interop issues and drives down the cost curve as technology
matures.
Mark
Chris
Couple of items you have
shaded gray (maybe) and white (preferred) the logic for them is not
clear to me:
- Why do you have 40 Km 1310 nm
with 10x10 DML and ML white and you have 1550 nm 40Km
gray?
- I also don't understand your reasoning
for not selecting 4x25G over 10Km of 1310 nm, this will be the
natural implementation when 4x25 become
available as you have for 40Km!
I expect early implementation
of 100G will be based on 10x10. But when the 4x25 becomes
available then
both 10Km and 40Km could go 4x25G instead of using a
more complex mux/de-mux.
Thanks,
Ali
Chris
Cole wrote:
Hi Marcus,
The 100GE Technical Feasibility Alternatives table only covers the two
proposed HSSG LAN reach objectives; 10km and 40km. There is currently no
WDM network objective in the HSSG. (In fact, a straw poll at the Dallas
meeting to not have a HSSG long haul PMD reach was supported.) So to
keep the coveted green shading we would like to encourage active
investigation efforts towards the use of serial techniques for the LAN
reach objectives.
In any case, I look forward to seeing your serial PHY contributions at
the next meeting.
Chris
-----Original Message-----
From: Marcus Duelk [mailto:duelk@alcatel-lucent.com]
Sent: Wednesday, April 04, 2007 12:06 PM
To: Chris Cole
Cc: STDS-802-3-HSSG@listserv.ieee.org
Subject: Re: [HSSG] <HSSG-FOAH> Meeting
Hi Chris,
thanks for the update. I am not speaking for a component vendor
so I don't know whether my feedback here can be considered as
a solution being "under active investigation". However, from a system
vendor's perspective I think that the serial solution (the last two rows
of your table) only makes sense for a WDM network which would
be at 1550nm and at reaches of 40km and beyond. These fields are
currently white but they are, at least from our perspective, under
active
investigation ... I will make further contributions on the serial PHY at
the next meeting(s).
Marcus
Chris Cole wrote:
During today's Fiber Optic Ad Hoc call we discussed updating the SMF
alternatives table. We simplified the table entries to three key
qualifiers that are required to enable technical feasibility. The
updated table is enclosed. Any comments on the proper assignment of
the
qualifiers will be appreciated.
We would also like to get input on the alternatives that are currently
under active investigation (green shading in the table) by HSSG
participants.
During the FOAC call, the 20G/25G - 1310nm alternatives, and 10G -
1550nm alternatives were confirmed as under active investigation.
We would like to find out if the 20G/25G - 1550nm, the 50G - 1310nm
and
100G - 1310nm alternatives (shaded green) continue to be under active
investigation.
We would also like to find out if any of the white areas are under
active investigation.
Please send an email indicating if you are investigating any of the
areas not confirmed during today's FOAC call.
The purpose is to accurately reflect which investigations are taking
place so that we can get an idea of what presentations we can expect
to
see during upcoming HSSG meetings. At this point we are not making any
selection between the alternatives.
Thank you
Chris
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