Steve,
I also questioned whether the CFI effort should include a 200G duplex MMF solution and a while back I spoke with Robert about it. He had at least one request for it to be included and he, as the leader of this effort, has chosen to let the process play out rather than screen out objectives prior to becoming a study group.
I have since spoken with a vendor who sees a need for a 200G MMF duplex solution. While I am not yet clear on the market opportunity it might have, I guess it depends on whether 200GbE ever becomes an enterprise speed. I do see the lag shrinking between cloud and enterprise so it could happen. I also note the MMF duplex solutions are mostly for brownfield applications so they need to be considered independently of SR4 solutions. Having both is not a conflict.
You correctly note that the IEEE did not support a duplex solution at 40G and 100G, but the need was there and the need is being satisfied by both proprietary and MSA efforts. As to not having 40G and 100G MMF duplex solutions, I note that we also did not standardize PSM4 at 40G or at 100G, but we are now doing so at 400G.
The decisions made in 802.3ba were done in 2008 and much has changed since then.
You correctly note that 802.3cd rejected a duplex 100G MMF solution (SR1.2) and instead chose an SR2 solution. It was my impression that .3cd prioritized breakout opportunity over brownfield MMF duplex. Will we see the applications that were suggested for SR2? I’m not sure. We will see deployment of both proprietary and MSA-based 100G duplex MMF solutions and we at LightCounting project a good future for this product category. So I respectfully disagree that because duplex solutions were not standardized at 40G and 100G that sets an unchangeable precedent.
As to OM5 reflected in the CFI deck, it’s has been reduced considerably to mostly “FYI” material. Reach is important, especially in multimode so it’s not wrong to suggest there is a new technology that could extend reach. The poll on reach you cite from 802.3ba was many years ago when data centers were much smaller. Since then, extended short reach (eSR) modules have been popular at 40G and this will repeat at 25G and 100G.
At this stage of the process, we need to get a study group formed to consider next-gen MMF objectives. If an objective is proposed in a study group for 200G MMF duplex, it will need to be defended and achieve the necessary vote threshold. The process will play itself out.
Dale Murray
From: Swanson, Steven E [mailto:SwansonSE@xxxxxxxxxxx]
Sent: Tuesday, October 10, 2017 12:11 AM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_NGECDC] Announcing NEA Ad Hoc call on Next-Gen MMF PMDs from noon to 1pm US Eastern time on 10/13 and 10/27
Robert,
In advance of the CFI meeting in Orlando, I would like to comment on the CFI wording. I fully support the work on NG MMF but cannot support the proposed wording of the motion. I am asking the group to consider modifying the wording to focus on 400 Gb/s PHYs over Fewer MMF Pairs than Existing Ethernet Projects and removing 200 Gb/s.
My rationale is as follows:
There is motivation to support a 400G solution over fewer pairs as an alternative to 400GBASE-SR16.
We are standardizing 200GBASE-SR4 in 802.3cd and there is no precedent for supporting a duplex solution at 200G – at least it was not supported at 40G or 100G – so why are we now thinking that it will be supported at 200G?
In IEEE 802.3ba, we defined 40GBASE-SR4; a proposal for a duplex solution was rejected by 802.3ba
· It was noted that a 4 lane parallel short wavelength based PMD is the highest density, lowest power consumption and lowest cost 100m solution and I don’t think that has changed.
· A straw poll to consider a duplex option yielded the result to develop a duplex based standard outside of 802.3ba by more than a 2 to 1 margin; several voted for the case that no duplex MMF solution was needed.
· 40GBASE-SR4 was adopted 85-0
In IEEE 802.3bm, we defined 100GBASE-SR4; a proposal for a duplex solution was not proposed in 802.3bm
· 100GBASE-SR4 approved
· To my recollection, no 100G MMF duplex option was proposed
In IEEE 802.3cd, we are defining 100GBASE-SR2 and 200GBASE-SR4; a proposal for a duplex solution (100GBASE-SR1.2) was rejected by 802.3cd
· Both a parallel and a duplex solution were considered in the 100G work
· A straw poll showed support for the parallel solution over the duplex solution by a 3 to 1 margin
· A subsequent motion to standardized the parallel solution passed by a 6 to 1 margin
There seems to be no reason to now support a duplex 200G solution when we have not standardized a duplex solution at 40G duplex nor a duplex solution at 100G.
Regarding the inclusion of OM5 in the CFI, I think it is a distraction that takes away from the main point of the CFI. It is clear that all perceived solutions can be supported on OM3 and OM4 and while some are purporting support for a 150m link length on OM5, this does not seem to be a requirement based on a poll in 802.3ba:
The goal for extending the reach on MMF should be:
A. at least 150m on OM3
B. at least 250m on OM4
C. both A and B
D. at least 200m on OM4
E. both A and D
F. there should be no goal for extended reach
Result:
A: 7
B: 3
C: 5
D: 1
E: 0
F: 27
It is for this reason that I would remove the slides on OM5; the inclusion of a 200G solution seems like an attempt to legitimize a certain transceiver/fiber combination (4 wavelength SWDM over OM5) when it is not really needed.
So, to summarize, I will fully support the CFI if it is worded as follows:
Motion at Closing Plenary:
Move that the IEEE 802.3 Ethernet Working Group authorizes the formation of a study group to develop a Project Authorization Request (PAR) and Criteria for Standards Development (CSD) responses for "Next-generation 400 Gb/s PHYs over Fewer MMF Pairs than Existing Ethernet Projects"
I will withdraw my support of the CFI if it is worded as follows:
Motion at Closing Plenary:
Move that the IEEE 802.3 Ethernet Working Group authorizes the formation of a study group to develop a Project Authorization Request (PAR) and Criteria for Standards Development (CSD) responses for "Next-generation 200 Gb/s and 400 Gb/s PHYs over Fewer MMF Pairs than Existing Ethernet Projects"
Best regards,
Steve
Steven E. Swanson
Senior Standards Manager
Distinguished Associate
Global Technology & Industry Standards
MT&E
Corning Optical Communications
800 17th Street NW
Hickory, NC 28603-0489
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m 607-725-1129
Standards are a bridge between markets and technologies; whoever controls the bridge controls the future…
From: Lingle, Robert L (Robert) [mailto:rlingle@xxxxxxxxxxxxx]
Sent: Friday, September 22, 2017 4:52 PM
To: STDS-802-3-NGECDC@xxxxxxxxxxxxxxxxx
Subject: [802.3_NGECDC] Announcing NEA Ad Hoc call on Next-Gen MMF PMDs from noon to 1pm US Eastern time on 10/13 and 10/27
All,
We will hold two telecons related to Next-Gen MMF PMDs from Noon to 1pm Eastern US time on Friday October 13th and Friday October 27th.
The agenda for the first call will be to discuss the wording of a motion to authorize a Study Group to be made at the closing Plenary in Orlando.
We will also discuss any final tweaks to the CFI deck.
The second call will only be held if there is any business not finished on the first call.
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