[ath9k-devel] multiple APs

[ath9k-devel] multiple APs

[Mark Schloesser]

Hi ath9k-devel,

we are currently playing around with some ath9k + hostapd setups at
university for testing purposes.
I already have a working WPA2 installation by now but as i am fairly new
to the linux based access point world there are some problems I am
facing. Also the surroundings of wireless drivers and applications seem
to be changing and evolving in the kernel world right now - so it's even
more difficult for me to find the solutions and best practices for our
research.

So I hope I am in the right place to ask some questions and get some
help or directions :)

I am using a Ubuntu amd64 installation on the machines here and we have
D-Link DWA-556 wireless cards in each of those. To get the setup working
I used the compat-wireless modules and compiled hostapd from svn trunk.
So hostapd is using the nl80211 driver backend (libnl). I configured
hostapd, fired it up using wlan0, set up some dhcp server and by then
had a working wpa2 access point.

Now... If i understand this correctly the atheros cards (old madwifi
driver and also ath5k/ath9k) are able to bring up multiple interfaces so
you can serve as AP and be a client station in parallel - or even could
serve two access points at the same time - one with WPA2 and one with WEP.

When I tried this I ran into a quite strange situation. I created a new
device in station mode and a second hostapd configuration that uses this
interface. At first I was able to bring up a second hostapd instance and
I even was able to see the wpa2 and wep networks on another machine but
I could not associate and also the hostapds were printing messages like
crazy.
I tried to reload the modules (ath9k and the 80211 ones) - and now
trying to bring up the second device i first got a network name conflict
due to the same mac address. I changed the mac address and now get "No
buffer space available" when I try to bring it up.

So my question is if I am totally doing anything wrong here? And also
perhaps someone could clarify the status of the drivers capabilites as I
am really confused by the ath9k documentation site and some
mailing-lists / webpages I stumbled upon during my research.

Another thing: Is there some possibility to make another machine with
ath9k card "repeat" the signal - like using WDS or some other method -
how is the state there?

I also tried to revert to using madwifi as it also supports our cards -
but I was not able to bring up an accesspoint there. Would it even be
the way to go - as it is more stable perhaps? Or should ath9k be okay?

I would be thankful for any hints!

Cheers,
Mark

[ath9k-devel] multiple APs

[Jouni Malinen]

On Fri, 2009-01-16 at 06:23 -0800, Mark Schloesser wrote:

> Now... If i understand this correctly the atheros cards (old madwifi
> driver and also ath5k/ath9k) are able to bring up multiple interfaces so
> you can serve as AP and be a client station in parallel - or even could
> serve two access points at the same time - one with WPA2 and one with WEP.

Yes, the hardware supports this. As far as ath9k state on this area is
concerned, support for virtual interfaces is currently disabled. There
is some code for this, but it is not yet complete and we are looking at
getting this enabled properly.

> I tried to reload the modules (ath9k and the 80211 ones) - and now
> trying to bring up the second device i first got a network name conflict
> due to the same mac address. I changed the mac address and now get "No
> buffer space available" when I try to bring it up.

That is the driver reporting refusing to allow the second interface to
be enabled. This limit will eventually be removed once the underlying
code works.

> Another thing: Is there some possibility to make another machine with
> ath9k card "repeat" the signal - like using WDS or some other method -
> how is the state there?

I haven't tested mac80211 WDS implementation for a while, but in theory,
this should work as-is or at least could be made to work with minimal
changes.

> I also tried to revert to using madwifi as it also supports our cards -
> but I was not able to bring up an accesspoint there. Would it even be
> the way to go - as it is more stable perhaps? Or should ath9k be okay?

Taken into account which mailing list you are posting to, the answer
should be quite obvious.. ;-)  You are much more likely to find people
here interested in resolving potential issues in ath9k and improving its
functionality.

- Jouni