[802.3_100GNGOPTX] Supporter lists
Participants,
If you wish to add supporters to your deck, but make no content changes, we will update the file on the website up to Monday at 5 pm PST. The upload date will change to ensure visibility of the newer file.
Dan
----- Reply message -----
From: "Brad Booth" <Brad_Booth@xxxxxxxx>
Date: Fri, Jan 20, 2012 1:34 am
Subject: [802.3_100GNGOPTX] Agenda and Presentations
To: <STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx>
Chris,
I am concerned about your statements.
While I do understand the point you're making about bait-and-switch, it is not a good idea to overly presume a solution when setting the objectives and documenting the 5 criteria.
I'm sure that you'd agree that the objectives and criteria should be written such that a broad range of possible solutions can be presented to the task force (once formed), and for the task force to decide the solution that they feel best meets the objectives and the criteria. It would also be preferential to not create multiple solutions to satisfy the shorter SMF demand. Per all the information shown today, this is a small market and two solutions would be ineffective in satisfying broad market potential. Let's learn from 10G and try not to create LX4 and LRM solutions that no one uses today.
As a further reminder that the SG should not be pre-supposing a solution: the final 10GBASE-T solution that was selected by the task force was far different than what was under consideration during the study group phase of the project, but the PAR, 5 criteria and objectives were broad enough to enable the task force to make what they felt was the best decision.
Cheers,
Brad
From: Chris Cole [mailto:chris.cole@xxxxxxxxxxx]
Sent: Thursday, January 19, 2012 7:06 PM
To: STDS-802-3-100GNGOPTX@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_100GNGOPTX] Agenda and Presentations
Hi Dan,
I would like expend on your comment that we have a jam-packed agenda. Not only do we have a large quantify of presentations, but we also have great depth and breadth of material in those presentations. Some of the technical results being presented are ground breaking and reflect major efforts. We should take pride in our Study Group for being a venue for reporting such high caliber work.
However, this does lead me to several concerns. The first concern is that we are rushing into adopting an SMF objective without sufficient justification.
Let's take as an example Sudeep's excellent presentation; bhoja_01_0112. As pointed out by Mark in nowell_01_1111 (page 8 table), PAM-16 has 1 laser instead of four lasers required for LR4. All things being equal that can translate to dramatic long term cost reduction, which Gary reconfirms in nicholl_01_0112. One seductive analogy that comes to mind is 10GE-LR versus 10GE-LX4. However, it is the implementation details that will determine whether this promise is real or an illusion. The problem is that many Study Group participants, including us, have no experience with high order PAM modulation, to enable a quick conclusion. We will need lots more time to digest this material.
A great example of why this understanding is critical comes from nowell_01_1111 observing that xA-yDPSK modulation also requires 1 laser instead of 4 lasers. There are published works showing Si implementations, so even the building blocks appear similar to the PAM-16 proposal. Fortunately, many Study Group participants already have multi-year experience with complex modulation and can immediately conclude that this approach is orders of magnitude away from being technically feasible as a low cost, low power client interface.
If we want to seriously consider PAM-16, we will need time to study it and understand the real implementation limitations. Mark and Gary have convinced me that this an area worthy of further study, but I do not see how that can be done by next week as urged by Dan. We will need at least two more meeting cycles to reach an independent conclusion if this is real. It is critical for the chair to have a sense of urgency to make forward progress. I fully internalized this during 802.3ba, where without John D'Ambrosia continuously herding the participating cats, it would have taken us a decade to finish. However, that needs to be balanced against allowing sufficient time for proper deliberation. if we want a SMF objective, we have to invest more time, unfortunately with no assurance that we will end up with an SMF objective at the end.
My second concern is that we are lumping together two very different applications and technologies into one SMF objective bucket, specifically parallel SMF for 300m to 500m applications and duplex SMF for 1km to 2km applications. A group of us discussed this at lunch during OIF, and Steve Trowbridge made a very insightful observations. In 802.3ba we did not have explicit statements about fiber cabling in either the MMF or SMF objectives, but very strong implications were there. Every participant understood that the MMF objective was for parallel MMF, and the SMF objective was for duplex SMF. Had we moved into Task Force and switched to duplex MMF (let's say using WDM) or parallel SMF (let's say because of cost), many in the larger optics community would have felt misled.
Looking at parallel SMF, we are reaching a critical mass for Technical Feasibility, among other reasons