What is Extra: rsn_ie ?

[Timo Pannes]

> A WPA2/RSN network will have an RSN IE in the beacons and probe response
> frames.
>
> A WPA network will have a WPA IE in the beacons and probe responses.
>
> A WEP network will have the "privacy" bit set in one of the IEs in the
> beacons and probe responses, and will contain neither a WPA nor an RSN
> IE.  (WPA/WPA2 networks usually also have the "privacy" bit set, but
> that may not be required by those standards.  I'm not sure.)

So how can I see which method is used? Do tools like kismet or ethereal show 
these differences? Or do they just guess somehow?