Support of CSA anf Fast BSS transition in wpa_supplicant

Jouni Malinen j
Fri Oct 14 14:05:23 PDT 2011

On Fri, Oct 14, 2011 at 10:10:31AM +0000, Atul Joshi wrote:
> 1.      Does wpa_supplicant support Channel Switch Announcement (as specified in 802.11h)?

I'm not aware of any driver that would expose suitable functionality for
controlling this from user space.. For most cases, it is probably easier
to address that in the 802.11 stack in kernel/firmware. If you have a
design in mind where it would sound useful to push this into
wpa_supplicant, it should be possible to do that, but kernel interface
additions would be needed first to be able to specify that the channel
needs to be changed without having to re-associate. I guess
wpa_supplicant could do that with re-association, but that adds some
extra latency to the process.

> 2.      Does wpa_supplicant support Fast BSS Transition (802.11r)? I can see a fast_reauth as a configuration flag but not sure if it means  fast bss transition (or fast roaming).

Yes, but fast_reauth parameter has nothing to do with this. You'll need
CONFIG_IEEE80211R=y in wpa_supplicant/.config and key_mgmt=FT-EAP (or
FT-PSK) in wpa_supplicant.conf instead of WPA-EAP/WPA-PSK (or include
both if you want to enable both AKMs so that this gets selected based on
what AP is doing).

> If wpa_supplicant does support these features , is there any documentation which indicates what parts are expected from the driver and what is handled by the wpa_supplicant?

Unfortunately there is not very good documentation on this.. Apart from
source code, you may be able to find some notes from the mailing list

Jouni Malinen                                            PGP id EFC895FA

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