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From: Ray Wang <rwang-+OaQ/>
To: Johannes Berg <>,
	'Richard Sharpe'
Cc: ""
	Tasheng Lin <tlin-+OaQ/>
Subject: RE: Proposal for an S1G header for radiotap
Date: Tue, 5 Feb 2019 19:19:14 +0000
Message-ID: <> (raw)
In-Reply-To: <>

Hi Johannes,

Thank you so much for your insight!

I agree with you that it is only an "aggregation" bit, The currently defined A-MPDU status field should be sufficient for that purpose as long as the SIG and SIG-A fields can be decoded in the corresponding S1G preambles, and A-MPDU status is populated or not populated accordingly.


-----Original Message-----
From: Johannes Berg [] 
Sent: Tuesday, February 05, 2019 1:55 AM
To: Ray Wang <>;; 'Richard Sharpe' <>
Cc:; Tasheng Lin <>
Subject: Re: Proposal for an S1G header for radiotap


> As to Aggregation related to A-MPDU, from 802.11ah -2016 spec it can 
> be seen the field is defined in SIG-2 of SIG field of S1G_SHORT 
> preamble, SIG-A2 of SIG-A field of S1G_LONG preamble, and SIG-2 of SIG 
> field of S1G_1M preamble.
> If looking at 802.11-2016 and Draft P802.11ax_D3.3 specs, the same 
> field is defined only in HT-SIG, but not in VHT-SIG-A and VHT-SIG-B, 
> and not in HE-SIG-A.
> From the spec perspective regarding the Aggregation field, 802.11ah is 
> different from 802.11n/ac/ax.

Well, OK. But we still use the A-MPDU field for HT/VHT/HE, even if those are also different. We've gone for a more semantic view I guess, and you can easily distinguish which kind of frame you had by the presence of HT/VHT/HE fields and/or channel information.

> As you pointed out, Richard, if the existing field can be reused it 
> might need some changes. If defining a new one, the existing one 
> probably also needs to be handled.
> What would you suggest is the best way to tackle it?

Can you say what you actually want to capture for aggregation data? So far you only had an "aggregation" bit, which could be easily indicated by the presence of the A-MPDU field. But the A-MPDU reference number in radiotap, which is something that obviously doesn't even exist in the
802.11 spec, would make sense so you know which PSDUs belonged into the same aggregate.


  parent reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-01  0:02 Richard Sharpe
     [not found] ` <>
2019-02-01 11:33   ` Johannes Berg
     [not found]     ` <>
2019-02-01 18:35       ` Richard Sharpe
     [not found]         ` <>
2019-02-01 22:03           ` yodazhong-Re5JQEeQqe8AvxtiuMwx3w
2019-02-01 23:04             ` Ray Wang
     [not found]               ` <CY1PR07MB27160AEE154215058A2CA4F2FF920-p80jK0/>
2019-02-05  9:55                 ` Johannes Berg
     [not found]                   ` <>
2019-02-05 19:19                     ` Ray Wang [this message]
2019-02-05  9:17             ` Johannes Berg

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