Re: [STDS-802-11-TGM] CID 1218 "poll" for opinions

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Hi Mark,

This text is in clause 9.2.2 Conventions, in the 9.2 MAC frame formats clause.

A statement that the reserved fields and subfields in MAC frames are set to 0 should be in this MAC frame convention clause.

So the first sentence is should be included in this clause, however I suggest that the sentence be changed as follows:

“Reserved fields and subfields in MAC frames are set to 0 upon transmission and are ignored when received.”

This clarifies that this text is only addressing MAC frames and therefore there is no need for Note 2.

Any description on what to do with PHY reserved fields or subfields should be in a PHY clause and not in this clause.

Delete Note 2.

The last sentence is about reserved values not about reserved fields or subfields and should be clarified as it is very hard to parse in its current form.

I suggest:

“Only defined values shall be inserted into MAC fields or subfields, reserved values shall not be inserted. If a reserved value is received the behavior is undefined.”

Note it may be preferred to say “should be inserted” and “should not be inserted”, as some implementors may use reserved values in a proprietary manner.

Regards,

Joseph Levy

New York

o: +1.631.622.4139

m: +1.516.835.9353

From: Mark Hamilton <mark.hamilton2152@xxxxxxxxx>
Sent: Tuesday, February 1, 2022 4:40 PM
To: STDS-802-11-TGM@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGM] CID 1218 "poll" for opinions

--- This message came from the IEEE 802.11 Task Group M Technical Reflector ---

All,

We’re looking for opinions…

On yesterday’s REVme call, we considered CID 1218:

"Reserved fields and subfields defined in this clause are set to 0 upon transmission and are ignored upon reception.

NOTE 2--This applies to reserved fields and subfields in MAC headers. Reserved fields and subfields in PHY headers might be set to a nonzero value upon transmission, and might not be ignored upon reception.

Reserved field and subfield values are not used upon transmission. Upon reception of a reserved field or subfield value, the behavior is undefined."

This is all very confusing. The last two sentences seem to contradict the first sentence. The middle throws in a contrast to PHY headers that does not seem to be supported anywhere else in the draft.

In our discussion, we determined that this text was expanded (to its current form, per above) in REVmd. It is believed this was to address some confusion that prior to the REVmd expansion (at least the addition of the NOTE), that there was some confusion that use of the term “reserved” in the PHY clauses might be interpreted as “tx as 0, ignore on rx” when actually it meant something different in the PHY.

Also, during our discussion, it was noted that the last two sentences are trying to talk about _values_ that are reserved (within a given field/element/etc., for example if 255 should never be used, etc.), in contrast to the first sentence which is talking about entire (sub)fields that are reserved. One suggestion was to reword the last two sentences to make the distinction more clear.

So, the questions to the group:

Is NOTE 2 clear, and useful/needed? We note that the first sentence clearly says “in this clause” (and this text is in clause 9), so that means the sentence does not apply to the PHY clauses. But, is it correct/necessary to exclude the PHY clauses? Is the sentence by itself (without the NOTE) clear enough in doing so?
Would the last sentences (after the NOTE) be more clear with wording such as, “Reserved values in non-reserved fields and subfields defined in this clause...” or is there another suggestion?

Replies to this (REVme) reflector, please.

Thanks. Mark

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