Wireshark-dev: Re: [Wireshark-dev] Patch: Prepare for some cleanups of 802.11ad
From: Guy Harris <[email protected]>
Date: Sat, 22 Aug 2015 14:30:41 -0700
On Aug 22, 2015, at 1:44 PM, Richard Sharpe <[email protected]> wrote:

> On Sat, Aug 22, 2015 at 1:32 PM, Guy Harris <[email protected]> wrote:
> 
>> No, I'd add a DMG field to radiotap, containing, among other values, an mcs subfield, with a Clause 21 MCS value in it.
> 
> Yes, in an ideal world. However, there will likely be captures out
> there for a while yet that do not have such a DMG field because it is
> not yet defined.

So software that reads radiotap captures and that cares about 11ad information needs to have a workaround wherein frames lacking a DMG field (which means "all frames", currently, as there isn't yet a DMG field) and having a channel frequency in the 11ad range have an 11ad PHY and, if they have MCS or VHT fields, ignore all items in those fields that don't apply to 11ad and *perhaps* interpret the MCS value in the MCS field as if it were an 11ad MCS value rather than an 11n MCS value.

>> I'm a software engineer, not an electrical engineer, so I'm not even remotely close to an authority on what radio-layer information would be useful, but a quick look at Clause 21 suggests that it might want to include a flag to indicate whether "Static Tone Pairing" or "Dynamic Tone Pairing" was used.
> 
> Can you make that suggestion on the radiotap mailing list?

I've followed up to your radiotap message with a suggestion for a DMG field.

> I can then communicate it to the appropriate parties and perhaps get
> them to join that mailing list as well.

If they're using radiotap for 11ad frames, they most definitely should join the mailing list.