[ath9k-devel] Questions about virtual managed interfaces.

[Rodolphe Marques <rodolphe.marques@ua.pt>]

Hi Ben,

I've been doing some work with ath9k virtual interfaces.
Well first the MAC is different. It usually differs in the first and 
last byte.
As for having 128 virtual interfaces I think that it is just impossible. 
For instance the default value for the scheduler is 500ms, which means 
that if you have 128 virtual interfaces each one will be served for 
500ms each 64 seconds. At least I think this is how they work.

I have been using only three virtual interfaces in managed mode and it 
works but the virtual interfaces get dissassociated a lot.

Best Regards,
     Rodolphe Marques

On 07/01/2010 06:39 AM, Ben Greear wrote:
> I'm trying to understand the features and limitations of the ath9k
> virtual phy and virtual station support.  I'm using the 2.6.34 kernel.
>
> First, I was able to create new virtual phys with the
> echo add>  /debug/ath9k/phy1/wiphy
> logic.
>
> That seems to work OK, and a new wlanX interface is created.
>
> The first potential problem I see is that the wlanX interfaces
> have the same MAC.  A previous post to this list made it appear
> that they would be XORd with phy-id or similar to get a unique
> MAC?
>
> It does appear that I can set the MAC address using 'ip link set ...', but I'm
> not sure if that is the right approach.
>
> I also tried adding new managed interfaces using
> iw phy phy1 interface add wlan1-1 type managed
>
> This also seems to work in as far as a new interface is created.
>
> Now, I am curious about configuring these things.
>
> *  If I have two managed wlans on the same phy, I assume they must
>      both be on the same channel?  Is there any support in the driver
>      to make sure that once one interface is associated on a particular
>      channel that another interface cannot start scanning on different channels
>      (and thus disrupt the first one)?
>
>      In some previous hackings of virtual station interfaces on ath5k, we
>      had all sorts of issues getting a bunch of interfaces associated
>      when using wpa-supplicant because one would start scanning and that would
>      dis-associate the others..over and over.
>
> *  If I want, say, 128 virtual station interfaces, does it make sense to try
>      to use 128 virtual phys, or should I aim at multiple stations per phy?
>
>      If anyone has tested the upper limits of how many virtual phys and/or
>      stations can be supported, I'm interested to know!
>
> Thanks,
> Ben
>
>