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The interleaving of meetings of the upper layer committees and boards is certainly a consideration. While the slide you included does not provide specific dates, I get the thrust that this interleaving is not favorable for a September meeting if the project approval happens in July rather than in March.
I need to correct my issue 4 assessment statement. I should have said TF rather than SG in last sentence, as corrected here.
Issue 4: new FEC or not new FEC
The case can be made to reuse the existing FEC, as you have begun. The case could also be made, for example, to eliminate FEC to address the low-latency market. I’d prefer to let this be decided in the TF phase, but in doing so the CSDs would need to remain agnostic about the latency aspects of the applications.
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Beth’s slides are saying that if the PAR and CSD are not approved until the July Plenary then the “upper committees” dates mean that the Task Force won’t be approved in time for the Sept Plenary. (See below).
Your deep dive into the subtleties is useful. You caught more of them than I did.
Issue 1: number of solutions per data rate.
The first two bulleted objective examples state a singular PHY.
The second two bullets could be interpreted as singular or multiple because the word “specifications” is plural. Does that plurality mean multiple solutions or that even one solution has multiple specs? If one solution per data rate were intended, this could be clarified by saying “Provide a physical layer specification …”
Issue 2: which data rate(s).
This choice could affect the CSDs, depending on how they were written. I agree that this choice should be made by the SG.
Issue 3: number of fiber pairs.
This choice could affect the CSDs, depending on how the CSDs were written. For example, the CSDs could be written such that the merits of fewer pairs could be stated generically without the need to know the number, or they could be written to describe applications that specific fewer-pair solutions would address. I’d prefer the former approach, so the pair counts get decided in TF phase.
Issue 4: new FEC or not new FEC
The case can be made to reuse the existing FEC, as you have begun. The case could also be made, for example, to eliminate FEC to address the low-latency market. I’d prefer to let this be decided in the SG phase, but in doing so the CSDs would need to remain agnostic about the latency aspects of the applications.
Regarding the meeting timing assessment, I think the March/May relationship is correct. But I think the July/November one should instead be July/September.
I think this brings up four different issues.
- Whether we think we should have objectives for just one or more than one solution for a given speed. I think this should be determined in Study Group as it would affect the CSD’s. (Robert assumed just one in the suggestions below and I think I agree with that).
- Whether we have objectives for both 200 and 400G. I think this should be determined in Study Group as it would affect the CSD’s. I think we should have a 200G objective (and the objective should be for a single fiber pair).
- Do we specify the number of fibers for the speed in the objectives. I think this does affect the CSD’s and would prefer to state 4 fiber pairs for the 400G objective.
- Whether we will allow new FEC/Logic. (i.e. PHY versus physical layer). We could leave that to Working Group but I think there will be a much stronger case for “Broad Market Potential” is we use the existing FEC/Logic so I prefer having “physical layer specifications”.
Beth had an interesting analysis about the study group timing for the 100G per lane group that I think would apply to this group as well. It shows that the study group either has to wrap up its work in March (with the first task force meeting in May) or wait until July (with a first task force meeting in Nov). My suggestion is that we target July and try to make the hard decisions in Study Group (i.e. have the more specific objectives).
Happy New Year!
Please consider several options for the form of objectives that will be produced by the Study Group for “Next-Gen 200 & 400 Gb/s PHYs over fewer MMF pairs than Existing Ethernet Projects & Standards.” These differences arise from 1) different forms of objectives in recent projects plus 2) whether we should choose the number of fiber pairs for a speed in Study Group vs. Task Force. (I only included single-pair and even numbers of fiber pairs, since those are the practical choices.) Historically we have not specified that a specific grade of MMF was required to meet the objective. I show a 400 Gb/s example below, but the options would apply to a 200Gb/s objective as well.
Q. What are the pro’s and con’s of these options? Which do you prefer?
- Define a 400Gb/s PHY for operation over fewer than 16 pairs of MMF with channel lengths up to at least 100 m.
- Define a 400Gb/s PHY for operation over (specify 1 vs. 2 vs. 4 vs. 8) pairs of MMF with channel lengths up to at least 100 m.
- Provide physical layer specifications which support 400Gb/s operation over fewer than 16 pairs of MMF with channel lengths up to at least 100 m.
- Provide physical layer specifications which support 400Gb/s operation over (specify 1 vs. 2 vs. 4 vs. 8) pairs of MMF with channel lengths up to at least 100 m.
Let us have a healthy discussion in advance of the 1/11 telecon, so we can begin to write down draft objectives.
Robert Lingle, Jr., Ph.D.
Acting Chair, IEEE 802.3 NGMMF Study Group
Director, OFS Systems & Technology Strategy