Re: multi-antenna handling

On Jul 8, 2013, at 1:59 AM, Johannes Berg <[email protected]> wrote:

> FWIW, I've now implemented this in Linux (in mac80211), although I start
> a new radiotap namespace for each antenna, separate from the first one,
> so you'll see
> 
> * any of: TSF, flags, rate, channel, MCS, a-mpdu, VHT, ...
> (new radiotap namespace)
> * ant signal: -40 dBm
> * anntenna: 0
> (new radiotap namespace)
> * ant signal: -45 dBm
> * anntenna: 1
> ... for however many antennas/chains there are.

So is the idea that, in the first radiotap-namespace block, there will be no per-antenna information such as the antenna signal - the only per-antenna information will be in the subsequent namespace blocks?

Context: somebody asked on ask.wireshark.org about a capture from a D-Link router running OpenWRT; he claims that the router has 2 antennas, but the capture has 3 antenna signal strength values, the first of which is in the first radiotap namespace:

	http://ask.wireshark.org/questions/33994/why-there-are-3-rssi-values-in-the-radiotap-header-for-a-dual-antenna-wireless-card