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Hi Ali,
If inner FEC is specified for plug and play DR and FR, the specifications for the no inner FEC mode falls out of it. It's the same implementation operating
at the lower rate. This leads to reduced performance, for example lower power budget. Whether that's useful is a separate question.
Given the confidence by TF participants in no inner FEC feasibility, we should revisit writing a spec. for only this case. This is especially true for DR.
One option is to specify DR only with end-to-end FEC, and FR and LR are with inner FEC, again subject to demonstrating feasibility.
Chris
From: Ali Ghiasi <aghiasi@xxxxxxxxx>
Sent: Wednesday, August 16, 2023 9:03 AM
To: STDS-802-3-B400G@xxxxxxxxxxxxxxxxx <STDS-802-3-B400G@xxxxxxxxxxxxxxxxx>
Subject Re: [802.3_B400G] [802.3_B400G_LOGIC] P802.3dj Joint Logic/Optics Track ad hoc agenda
8/15/23
Hello Chris,
One of the key reason for success of IEEE 802.3 standards as said is the Five Criteria (CSD) and technical feasibility, on the DJ website under Technical Feasibility we have:
At a minimum, address the following items to demonstrate technical feasibility:
a) Demonstrated system feasibility.
b) Proven similar technology via testing, modeling, simulation, etc.
c) Confidence in reliability.
I am sure at some point in time 200 Gb/s/lane optics will evolve sufficiently where one with confidence and reliable operate such link with just KP4 FEC.
If for some reason the future TX technology (2nd Gen Sipho/TFLN ??) are ready for deployment in 12-18 months then there is no reason to define PMDs with inner FEC!
We should not hack defining future optics PMDs based on 1st Gen 200G TX optics!
Thanks,
Ali Ghiasi
Ghiasi Quantum LLC
One perspective is that we create new objectives for the same reach, with independent specs. at a lower rate and only end to end FEC. Part of the motivation is that a better TX modulator removes the need for inner FEC. If we adopt this approach,
we will have two solutions to the same problem: 1) "bad" TX with inner FEC to make up for the badness, 2) "great" TX without the need for inner FEC. Unfortunately, we have 802.3 Five Criteria to contend with. Distinct Identity clearly states there will be
one solution to one problem. If DI doesn't apply here, then we might as well discard it, and going forward only have 802.3 Four Criteria.
FEC bypass should be a lower performance operating mode for the same HW. This is the basis on which I supported moving forward with it. We have to add a full set of specifications for this mode. This is why the general approach we take for ER
is good precedent. The Plug-and-play spec column is at the higher rate with inner FEC. The Engineered spec column is at the lower rate with inner FEC bypassed. An end user can then look at the spec, and for example conclude that for their shorter reach ML
clusters, the FEC bypassed mode works just fine. However, the specifications lead to one component type. The industry does not need component type proliferation driven by IEEE. That leads to market fragmentation.
Alternatively, if we really believe that "good" TX technology is available, let's not bother having an inner FEC. Let's forget writing a spec for "bad' TX and write one spec. for end-to-end FEC only.
Either way, we do not need new objectives. We have single 500m and 2km objectives, each with two modes (Plug-and-play and Engineered) with different levels of performance and operating parameters like rate, or just one Plug-and-play mode without
inner FEC.
Chris
Hi Everyone,
All files for tomorrow’s joint optics/logic ad hoc meeting are posted
here [ieee802.org].
Call in details are available
here [ieee802.org].
The technical presentations in the agenda are:
- " FEC Bypass: Procedural Considerations " presented by John D’Ambrosia, Futurewei, US Subsidiary of Huawei
- " Performance Evaluation of Inner FEC Synchronization Methods " presented by Xiang He, Huawei
- " Specifying BER in PMD clauses " presented by Adee Ran, Cisco
- " DGDmax specification for 10km Ethernet" presented by Maxim Kuschnerov, Huawei
We may be holding a straw poll after the first presentation to gather directional feedback for Task Force leadership.
I want to remind all teleconference meeting participants to review the following documents prior to participation in an IEEE 802.3 meeting teleconference:
- IEEE SA patent policy
- IEEE SA Copyright Policy
- IEEE SA Participation Policy
Thanks,
Mark N
IEEE P802.3dj optics track leader
And
Mark G
IEEE P802.3dj architecture and logic track leader
Reminder to everyone about next Tuesday’s
IEEE P802.3dj joint logic and optics track ad hoc meetings.
There are deadlines this week for agenda requests (Wednesday) and presentation submission (Friday).
Regards,
Mark
This email serves to announce the next IEEE P802.3dj joint logic and optics track ad hoc meetings.
Meeting dates, times and deadlines:
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Meeting
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Agenda request deadline (5pm PT)
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Contribution submission deadline (5pm PT)
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Tues Aug 15th, 7am to 10am PT
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Wed Aug 9th
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Fri Aug 11th
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Tues Aug 29th, 7am to 10am PT
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Wed Aug 23rd
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Fri Aug 25th
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Coming out of the May plenary meeting, we identified a number of areas where more information is needed or more consensus is needed. The purpose of these ad hoc meetings is allow discussion and contributions
on any of these topics. We are holding it joint between the optics and logic teams as a number of these topics relate across both areas.
The goal will be to enable contributors to better refine proposals or provide information relevant to future decisions ahead of the July Plenary meeting. With this being an ad hoc meeting, no decisions
can be made but informative straw polls are possible.
At this point, we anticipate topics to potentially include:
-
Inner FEC padding and synchronization
- FEC bypass proposal
- Updates on IMDD optical baseline proposals (nothing adopted yet)
- Updates on coherent optical baseline proposals (nothing adopted yet here too)
But this is not a complete list of potential topics.
If anyone, does wish to make a short presentation in line with above please make a request by the dates noted above. Please email myself, Mark Gustlin (and John D'Ambrosia, please) the following
information:
- Name of presenter
- Affiliation of presenter
- Title of presentation
- Length of time requested (this should include time for questions and answers – presentation time, excluding Q&A, will be at the discretion of the chair, and should be
assumed to be limited to 30 min)
- Brief description of topic
The presenter shall e-mail a PDF, soft-copy version of the presentation to me (and John D'Ambrosia, please) in advance of the meeting per above dates..
Please adhere to the Presentation Style Guidelines. Also, to support the web site search tool used by the IEEE P802.3 web site the 'Document Information' fields of the PDF file must be completed
as follows:
- Title: Title of presentation
- Author: Name(s) of author(s)
- Subject: IEEE P802.3dj Task Force
I want to remind all teleconference meeting participants to review the following documents prior to participation in an IEEE 802.3 meeting teleconference:
- IEEE SA patent policy
- IEEE SA Copyright Policy
- IEEE SA Participation Policy
Thanks,
Mark N
IEEE P802.3dj optics track leader
And
Mark G
IEEE P802.3dj architecture and logic track leader
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