WPS with many WPS enabled APs

Jouni Malinen j
Thu Jun 17 12:45:42 PDT 2010

On Thu, Jun 17, 2010 at 03:20:34PM -0400, Patrik Lahti wrote:

> One thing that I'm wondering about is: It seems that wpa_supplicant 
> takes scan results and attempts to do the WPS exchange with APs with 
> "[WPS]" in the scan results in the order they appear. I.e. it'll attempt 
> the first WPS AP a few times, and if that fails it'll move on the next 
> WPS AP, and so on...

> The potential problem is that when there are many APs with announcing 
> [WPS] it may take a while to get to the actual AP which I've punched in 
> the PIN number into, and so it might time out...

> Is this just a known limitation of WPS? Is this the fault of the driver 
> presenting the scan results in the wrong way? Or not presenting 
> up-to-date scan results as expected by wpa_supplicant? Or is there an 
> improvement to wpa_supplicants scanning algorithm that's possible?

It is a workaround that is unfortunately needed with some of the
deployed WPS APs.. There are some optimizations to this in the current
development tree that will hopefully improve the likelihood of the
correct AP being selected more quickly. Furthermore, there is ongoing
work to improve this.

Jouni Malinen                                            PGP id EFC895FA

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