Virtual WiFi on Linux?

[Jim Thompson]

On Oct 19, 2005, at 9:59 PM, Dan Searle wrote:

> Hi,
>
> Talking somewhat specifically about Madwifi here, but what I'm saying
> could be taken in a more generic sense....
>
> Surely to run virtual AP's you need the NIC's to possess more than one
> MAC address, i.e. for 16 Virtual AP's, you need 16 MAC addresses.

Well, to run one style of "Virtual AP", you would want 16 different  
BSSIDs, yes.

> Then, run 16 separate MAC layers with some kind of modification to the
> HAL to share (schedule) the PHY layer between the 16 MAC layers.

No, you 'multiplex' 16 instances of the "upper MAC" over a single  
instance of the "lower MAC".

> I.e. run 16 802.11 protocol stacks on top of a modified HAL which
> contains some kind of intelligent PHY scheduler, to make sure we're
> fair about how much time each MAC layer gets on the PHY.

No HAL modifications are required to implement such a scheduler.

> Received frames are not under our control, so all the scheduler would
> have to do is share out the PHY transmit buffer (e.g. SFQ?).

Huh?

> I think this would require either modifying any existing lower MAC
> (HAL), or perhaps writing a completely new lower MAC (HAL).

The HAL (in madwifi anyway) is not the "lower MAC".

> Regards, Dan...
>
> Thursday, October 20, 2005, 8:48:39 AM, you wrote:
>
>
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>
>
>> Lancom is using something like that with atheros cards (L54A/AG).
>> You can configure up to 8 SSIDs with different security (WEP, WPA1,
>> WPA2, etc). Every SSID has a different MAC (they increment the  
>> first MAC
>> Byte). While using this feature i saw that the throuput went down  
>> with
>> more then one SSID. I think its a matter of fragmentation on  
>> wireless layer.
>>
>
>
>> Regards
>>
>
>
>> Math
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>
> --
>
> Dan Searle
> Adelix Ltd
> dan.searle at adelix.com web: www.adelix.com
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