Re: [STDS-802-11-TGM] 11me/D3.0 CID 4341 (what BA params can be modified

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Hello Mark,

From my understanding, whenever the block ack agreement is renegotiated, the starting sequence number will be refreshed.

So, all the MPDUs that were waiting for an BlockAck will be gone and the originator and the responder can sync at the start of the renegotiation.

The reason why the TID is special is because the block agreement is on TID basis (i.e., if the TID is different, then the negotiation is different), as I understand.

So I agree only on your a) and I suggest leave the other places as is.

Best regards,

tomo

From: Mark Rison <m.rison@xxxxxxxxxxx>
Sent: Thursday, June 15, 2023 5:26 PM
To: STDS-802-11-TGM@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGM] 11me/D3.0 CID 4341 (what BA params can be modified)

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

I haven't had any response on this, so I will try to float a possible

direction and see if this provokes a response:

a) Revert the "When Block Ack operation is modified, only the timeout can be changed."

in 9.6.4.1 (anyway, this is more behaviour than format)

b) State in 11.5.4 Error recovery upon a peer failure that BA agreement

modification also resets the inactivity timer. Maybe also tweak

penultimate para of 10.25.4 Teardown of the block ack mechanism

to cover BA agreement modification

c) Put a NOTE in 10.25.2 and 11.5.1 along the lines of

NOTE—The parameters of the agreement are identified in

9.6.4.2 ADDBA Request frame format and

9.6.4.3 ADDBA Response frame format. The handling of a

modification to any given parameter other than the timeout

is parameter-dependent. Care should be taken if any

restrictions are introduced (e.g. the new buffer size is

smaller than the current buffer size, and there are MPDUs

outside the range of the new buffer size).

[I'm mentioning 9.6.4.2 as well as 9.6.4.3 because I'm not 100%

confident everything is entirely governed by the ADDBA Response.]

Thanks,

Mark

Mark RISON, Standards Architect, WLAN English/Esperanto/Français

Samsung Cambridge Solution Centre Tel: +44 1223 434600

Innovation Park, Cambridge CB4 0DS Fax: +44 1223 434601

ROYAUME UNI WWW: http://www.samsung.com/uk

From: Mark Rison <m.rison@xxxxxxxxxxx>
Sent: Friday, 26 May 2023 19:55
To: STDS-802-11-TGM@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGM] 11me/D3.0 CID 4341 (what BA params can be modified)

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

CID 4341 asks what parameters of a block ack agreement can be modified.

If you have any answers to the questions highlighted in cyan below, or

any other thoughts on the matter, please do respond!

Identifiers

Comment

Proposed change

CID 4341

Mark RISON

10.25.2

9.6.4.1 says "When Block Ack operation is modified, only the timeout can be changed." but 10.25.2 says "All parameters of the agreement may be changed except for the TID." and 11.5.1 says something similar

Decide one way or the other. If buffer size and timeout can be changed, describe what happens if the new values are smaller than the current, and the current window/idle time exceed the new limits [needs discussion]

Discussion:

We currently have:

9.6.4.1 Block Ack Action field(#3729)

ADDBA Request and ADDBA Response frames are used to set up or to modify block ack operation(#3518) for a specific TC, TS, or GCR group address. (#3172)When Block Ack operation is modified, only the timeout can be changed.

10.25.2 Setup and modification of the block ack parameters

(#1807)A block ack agreement may be modified by the originator by sending an ADDBA Request frame ((#3174)see 11.5.2 (Setup and modification of the block ack parameters), except that MLME-ADDBA primitives are not used). All parameters of the agreement may be modified except for the TID.

11.5 Block ack operation

11.5.1 Introduction

(#3174)Block ack agreements may be set up, modified by the originator, or deleted from the MAC (see 10.25.2 (Setup and modification of the block ack parameters)) or from the SME. The setup, modification by the originator and deletion of block ack agreements from the SME is described in this subclause. All parameters of an agreement may be modified except for the TID.

An ADDBA Request frame is defined in Table 9-445—ADDBA Request frame Action field format and contains the following fields:

Block Ack Parameter Set, which contains A-MSDU Supported, Block Ack Policy, TID and Buffer Size subfields

Block Ack Timeout Value

Block Ack Starting Sequence Control, which contains a SSN

GCR Group Address element (optional), which contains a GCR group address

Multi-band (optional), which contains loads of stuff

TCLAS (optional), which contains loads of stuff

ADDBA Extension (optional), which contains No-Fragmentation and HE Fragmentation Operation subfields

EDMG Flow Control Extension Configuration (optional), which contains loads of stuff

SAR Configuration (optional), which contains quite a lot of stuff

Q1: is it really OK for all of these to be modified? E.g. change A-MSDU support or GCR address or TCLAS or fragmentation or Multi-band/EDMG/SAR config?

An ADDBA Response frame is defined in Table 9-446—ADDBA Response frame Action field format and contains the following fields:

Block Ack Parameter Set

Block Ack Timeout Value

GCR Group Address element (optional)

Multi-band (optional)

TCLAS (optional)

ADDBA Extension (optional)

EDMG Flow Control Extension Configuration (optional)

SAR Configuration (optional)

Originator Preferred MCS element (optional)

Q2: is it really OK for all of these to be modified, even if not modified in the request (either w.r.t. the original request, or the original response)?

Q3: even if we focus on the “core” parameters, i.e. timeout and buffer size, what if the new values are smaller than the current values, i.e. there has been no traffic for more than the new timeout, or the new buffer size is smaller than the current outstanding window size?