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Re: [802.3_B400G] [802.3_B400G_178B] Annex 178B Direction and the Scope of IEEE P802.3dj

Hi John,

I will summarise the scope of the IEEE P802.3dj PAR as defining physical layer specifications of 200 Gb/s, 400 Gb/s, 800 Gb/s, and 1.6 Tb/s, utilising >= 200 Gb/s signalling over copper and single-mode fibre PMDs. As you are aware from our previous discussions regarding PAR scope, I aim to interpret the scope statement in the broadest possible manner.

Since defining physical layer specifications includes defining their sublayer interfaces, and since the PAR is silent on this subject, I believe it is within the scope of the project to define physical layer specifications using either existing physical layer interfaces (e.g., 800GMII and 800GAUI-8), or using new physical layer interfaces defined as part of the project (e.g., 1.6TMII and 800GAUI-4). I also believe that defining new features (e.g., path startup function) for the new physical layer interfaces that do not exist for the existing equivalent physical layer interfaces is also within the scope.  

Additionally, I believe that necessary modifications to existing physical layer interfaces to support the new physical layer specifications are within scope. However, I don't see anything in the PAR scope beyond defining new physical layer specifications using the specific PMDs. As a result, I don't believe that the PAR scope supports modifying existing physical layer interfaces for anything beyond what is necessary to support the new physical layer specifications. I, therefore, don't believe that it is within the scope of the PAR to modify existing physical layer interfaces to add new features.

Finally, since the scope includes '... utilising >= 200 Gb/s signalling over copper and single-mode fibre PMDs', I do not believe it is within the PAR's scope to define physical layer specifications that are not based on copper or single-mode fibre PMDs using ≥ 200 Gb/s signalling.

Best regards,
  David

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From: John D'Ambrosia <jdambrosia@xxxxxxxxx> 
Sent: 29 August 2025 18:45
To: STDS-802-3-B400G-178B@xxxxxxxxxxxxxxxxx
Subject: [802.3_B400G_178B] Annex 178B Direction and the Scope of IEEE P802.3dj

All,
Given the WG Recirculation Ballot currently underway, I have spent time pondering the presentation & discussion in the Annex 178B ad hoc this week.
One of the observations noted in the presentation was:
       AUI components is made up of xAUI-n's (constrained by xAUI-n definition) & PMDs (no constraints)
In combination with an output of the ad hoc discussion:
       x-AUI-n needs clarification to be more inclusive of other AUIs (i.e. other than those defined in 802.3dj)
The group essentially noted it wanted to define this annex to be generic in terms of PMDs and AUIs.
As I noted at the end of the presentation - 
       Solution needs to be considered for project scope. 
Per the PAR (https://urldefense.com/v3/__https://www.ieee802.org/3/dj/projdoc/P802d3dj_PAR.pdf__;!!NpxR!hGWXDqh0bevhlkdLbKSFeJRP2W1zp25CgLiTObQLkZPB7-dyBk3ffcOSFqkTAYfvTixp4RCOVUMzKg$) 
5.2.b Scope of the project: 
Define Ethernet MAC parameters for 1.6 Tb/s. Define physical layer specifications, and management parameters for the transfer of Ethernet format frames at 800 Gb/s and 1.6 Tb/s over copper and single-mode fiber physical medium dependent (PMD) sublayers based on 200 Gb/ s or greater per lane signaling technologies. 
Using these new definitions for 800 Gb/s and 1.6 Tb/s, define physical layer specifications and management parameters for the transfer of Ethernet format frames at 200 Gb/s and 400 Gb/s, when applicable.
The first paragraph clearly limits the PMDs that can be addressed to those PMD sublayers based on 200 Gb/s or greater per lane signaling technologies.
So it would seem to me that this annex needs to be constrained to PMDs that utilize >= 200 Gb/s signaling:
For 200GbE: 200GBASE-CR1, 200GBASE-KR1, 200GBASE-DR1;200GBASE-DR-1-2; 
For 400GbE: 400GBASE-CR2, 400GBASE-KR2, 400GBASE-DR2;400GBASE-DR-2-2
For 800GbE: 800GBASE-CR4;800GBASE-KR4; 800GBASE-DR4;800GBASE-DR4-2; 800GBASE-FR4; 800GBASE-FR4-500;800GBASE-LR4;800GBASE-LR1;800GBASE-ER1;800GBASE-ER1-20
For 1.6TbE: 1.6TBASE-CR8; 1.6TBASE-KR8;1.6TBASE-DR8;1.6TBASE-DR8-2
Additionally, this part of the scope statement needs to be considered:
Define physical layer specifications, and management parameters for the transfer of Ethernet format frames at 800 Gb/s and 1.6 Tb/s over
Physical layer specifications defined in this project have focused on 200 Gb/s signaling for the AUIs for 200GbE, 400GbE, 800GbE, and 1.6 TbE and 100 Gb/s signaling for 1.6 TbE.  Therefore 25 Gb/s and 50 Gb/s based AUIs (which was not used to define physical layer specifications for 800GbE or 1.6 TbE) for 200 GbE and 400 GbE do not appear to be in scope.
Additionally, while we defined 100 Gb/s signaling for 1.6TbE, the 100Gb/s based AUIs for 200GbE, 400GbE, and 800GbE are already defined, and the scope does not state "modify existing physical layer specifications."  Furthermore, the objective for 100 Gb/s based 1.6 TbE AUI was adopted to support test equipment, which IMO doesn't seem to need "ILT."  Do we really need to devote our limited resources to it?  I am struggling to believe this should be a priority.  
Furthermore, if we include other PMDs and AUIs, the TF, to do its job properly, needs to consider them, otherwise how can we be assured they actually work - and this raises an issue for me as Chair, hearing presentations that are clearly out of scope.
This is a discussion that needs to be had with the WG Chair, David Law.   David - if you are reading this email, it would be appreciated if you can reply to this email.
So, IMO, Annex 178B should address: 
PMDs that utilize >= 200 Gb/s signaling:
For 200GbE: 200GBASE-CR1, 200GBASE-KR1, 200GBASE-DR1;200GBASE-DR-1-2; 
For 400GbE: 400GBASE-CR2, 400GBASE-KR2, 400GBASE-DR2;400GBASE-DR-2-2
For 800GbE: 800GBASE-CR4;800GBASE-KR4; 800GBASE-DR4;800GBASE-DR4-2; 800GBASE-FR4; 800GBASE-FR4-500;800GBASE-LR4;800GBASE-LR1;800GBASE-ER1;800GBASE-ER1-20
For 1.6TbE: 1.6TBASE-CR8; 1.6TBASE-KR8;1.6TBASE-DR8;1.6TBASE-DR8-2
C2C and C2M AUIs based on 200 Gb/s 
200GAUI-1, 400GAUI-2, 800GAUI-4, 1.6TAUI-8.
Full disclosure - I will be submitting comments based on this thought process.
Regards,
John D'Ambrosia
Chair, Annex 178B Ad hoc
Chair, IEEE P802.3dj Task Force

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