Re: Correct radiotap header for 802.11ad

On Aug 22, 2015, at 1:59 PM, Guy Harris <guy-FrUbXkNCsVf2fBVCVOL8/[email protected]> wrote:

> From the *radiotap* point of view, I would say that the last field is incorrect because the page for the MCS field on the radiotap site says:
> 
> 	The mcs field indicates the MCS rate index as in IEEE_802.11n-2009.
> 
> which, if we update it to say "as in Clause 20 of IEEE 802.11-2012", means it has values from 0 to 76, with modulations different from the ones in 11ad's Clause 21, i.e. the radiotap MCS field is *not* appropriate for 11ad.

For what it's worth, it appears that the wil6210 driver:

	https://wireless.wiki.kernel.org/en/users/drivers/wil6210

uses the MCS field and its mcs value for 11ad.  It can also be configured to supply raw "PHY data" with a vendor-namespace field.

So code that processes radiotap headers, such as Wireshark's radiotap-header dissector, will have to interpret packets with an MCS field and a channel frequence in the 11ad range as being 11ad packets, and treat the mcs value in the MCS field as an 11ad MCS, not an 11n MCS.