Dual band

[Fejes József]

On Tue, Jan 2, 2018 at 4:30 PM, Ben Greear <greearb at candelatech.com> wrote:
>
>
> On 01/02/2018 07:25 AM, Fejes József wrote:
>>
>> On Tue, Jan 2, 2018 at 4:14 PM, Ben Greear <greearb at candelatech.com>
>> wrote:
>>>
>>>
>>>
>>>
>>> On 01/02/2018 04:28 AM, Fejes József wrote:
>>>>
>>>>
>>>> Hi,
>>>>
>>>> This question was asked a couple of years ago (eg. here
>>>> http://lists.infradead.org/pipermail/hostap/2012-January/025117.html)
>>>> with a negative answer.
>>>>
>>>> However, it seems like things have changed in Linux at least. Recent
>>>> wifi cards support multiple virtual interfaces with multiple channels.
>>>> Eg. with the command: iw dev wlan0 interface add wlan1 type __ap .
>>>> Thus even if I have one card with one chip, I can have multiple wlan
>>>> devices and the card will handle communication with different
>>>> bands/channels accordingly.
>>>
>>>
>>>
>>> Which cards do you think support this option?
>>>
>>
>> For example iw reports this for a BCM4366 (it also reports both 2.4GHz
>> and 5GHz bands in the channel list):
>>
>> valid interface combinations:
>> * #{ managed } <= 1, #{ P2P-device } <= 1, #{ P2P-client, P2P-GO } <= 1,
>>   total <= 3, #channels <= 1
>> * #{ managed } <= 1, #{ AP } <= 1, #{ P2P-client } <= 1, #{ P2P-device }
>> <= 1,
>>   total <= 4, #channels <= 1
>> * #{ AP } <= 4,
>>   total <= 4, #channels <= 1, STA/AP BI must match
>>
>> Last combination is the key, you can create 4 AP-type interfaces at
>> the same time. Although it says channels<=1 which is weird for
>> dual-band but whatever. I've seen pastes where channels was 2.
>
>
> I guess if you could find something that would give you multiple concurrent
> channels
> support, then it might work.  But, in that case, it would seem simpler all
> around to just have it act as two radios.
>

I've been looking at various cards in the past few days and it seems
like many of the newer ones support these combinations.

If the chip reports the necessary combinations, it means you can
create multiple virtual interfaces (wlan0, wlan1, ...) and then the
one chip appears as multiple radios. And this is what I'm asking, does
hostapd work with these? And do I have to create these virtual
interfaces up front, or can hostapd create/destroy them as needed? All
the guidance out there says you need 2 chips to have a dual band AP,
but I'm hoping this is no longer the case.

> Thanks,
> Ben
>
>
>>
>>
>>
>>>
>>> Thanks,
>>> Ben
>>>
>>>>
>>>> My question is, does hostap work with such virtually created
>>>> interfaces for the same chip?
>>>>
>>>> It would be even better if hostap could create such virtual interfaces
>>>> on its own. Is it supported or is it going to be supported?
>>>>
>>>> Cheers,
>>>> Jozsef
>>>>
>>>> _______________________________________________
>>>> Hostap mailing list
>>>> Hostap at lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/hostap
>>>>
>>>
>>> --
>>> Ben Greear <greearb at candelatech.com>
>>> Candela Technologies Inc  http://www.candelatech.com
>>
>>
>
> --
> Ben Greear <greearb at candelatech.com>
> Candela Technologies Inc  http://www.candelatech.com