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Re: [802.3_SPMD] Comment 194



Thank you, Chad.  For others, this became a big ticket item because when Chad and I were discussing the proposed responses it became clear that we were talking about different meanings of “mixed”.

It sounds now like we are talking only about the meaning of the output of the management object. An MPD can be a ‘type 0’ ‘type 1’ or a ‘type Mixed’ (able to be a 0 or 1), and an MPSE in the state diagram detects ‘type Mixed’ as a separate thing… It sounds like for the management object we want:

Type 0 – only type 0 or a mixture of type 0 and type Mixed MPDs are detected.

Type 1 – only type 1 or a mixture of type 1 and type Mixed MPDs are detected.

Or

Mixture – a mixture of type 0 and type 1 MPDs are detected.  This includes a mixture which also has Type Mixed MPDs.

 

We still need to cover the case where ONLY Type Mixed are discovered, which was the case considered in the comment, and we need to decide if we want to a value of

Mixed – only type Mixed MPDs are detected.

 

Regardless, it seems the required solution goes beyond what the commenter’s resolution (my resolution) envisioned, needing the extra words in type 0, type 1 and the addition of mixture…

 

George Zimmerman, Ph.D.

President & Principal

CME Consulting, Inc.

Experts in Advanced PHYsical Communications

george@xxxxxxxxxxxxxxxxxxxx

310-920-3860

 

From: Chad Jones (cmjones) <00000b60b3f54e8d-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, January 7, 2025 1:11 PM
To: STDS-802-3-SPMD@xxxxxxxxxxxxxxxxx
Subject: [802.3_SPMD] Comment 194

 

As I’m making my way through the comments, I will use the reflector to discuss things that I don’t think need a whole presentation. Here’s my first one:

 

Comment 194

30

30.17.1.1.3

28

50

T

the aMPSETypeDiscovery enumerated values miss the case where type "mixed" MPDs are discovered…  they just have the case where Both type 0 and type 1 MPDs have been discovered.  This case should also include type "mixed" discovered, as listed in 30.17.2.1.1 (as well as in clause 189)

Change description of "mixed" to read "Type Mixed, or a mixture of MPD Types"

PROPOSED ACCEPT IN PRINCIPLE.



TFTD.



(Editor's note: We need to determine with "Mixed" is a Type, or if it is just that the MPD change types just like the MPSE can change types.)

 

Commentor has a point that mixed is missing from this text, but the remedy doesn’t fix it. The answer is here is that we are misusing mixed in this context. Type0 should mean that the PSE has only discovered type 0 and type mixed MPDs. Similarly type1 means only type 1 and type mixed MPDs are present. Mixed REALLY means I have a mixture of type 1 and type 0, and in this case we don't care it there are any type mixed present. The main point is I have two PD types that are incompatible with interoperation. We should find a new name for mixed here, "blended" is a better description. There could be a fourth case called mixed where it only discovered type mixed MPDs and the PSE can then power as whatever type it is.

 

Regards,

 

Chad Jones

Principal Engineer, Cisco Systems

Executive Secretary, IEEE 802.3 Working Group

Chair, IEEE P802.3da Task Force

Principal, NFPA 70 CMP3


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