Adhoc-demo support in mac80211

Adhoc-demo support in mac80211

[ming li]

Folks,

I am wondering how hard it is to add support for ahdemo mode in mac80211.
My understanding of ahdemo is that it does not have the beacons or the
association process as in adhoc mode. Does this mean that I can just
comment out the beacon and association code of adhoc mode and make it
ahdemo? Any info will be highly appreciated.

Thanks,

Ming

Re: Adhoc-demo support in mac80211

[Kalle Valo]

ming li <mingli@cs.umass.edu> writes:

> I am wondering how hard it is to add support for ahdemo mode in mac80211.
> My understanding of ahdemo is that it does not have the beacons or the
> association process as in adhoc mode.

Can you provide more information about this Adhoc-demo mode? I have
never heard of it.

-- 
Kalle Valo

Re: Adhoc-demo support in mac80211

[Johannes Berg]

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On Tue, 2009-03-24 at 19:55 +0200, Kalle Valo wrote:

> Can you provide more information about this Adhoc-demo mode? I have
> never heard of it.

I /think/ it's a pre-standards version of IBSS. I think I had an ancient
11b card that supported it somehow...

johannes

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Re: Adhoc-demo support in mac80211

[ming li]

Hi,

The adhoc-demo mode is also called pseudo-adhoc mode. It is simply the
ad-hoc mode without control pkts. It does not probe for or associate
to adjacent adhoc networks. The user has to set all the nodes to the
same channel manually. The good thing of adhoc-demo is that it does
not have the beaconing overhead or the IBSS merging/splitting problem.

We used adhoc-demo mode under madwifi for long time and it worked
perfectly. Now we have to shift to ath9k but found out the mode is not
supported. I am just wondering if there is an easy way to hack adhoc
mode to disable beaconing and association.

Thanks,

Ming


On Tue, Mar 24, 2009 at 1:55 PM, Kalle Valo <kalle.valo@iki.fi> wrote:
> ming li <mingli@cs.umass.edu> writes:
>
>> I am wondering how hard it is to add support for ahdemo mode in mac80211.
>> My understanding of ahdemo is that it does not have the beacons or the
>> association process as in adhoc mode.
>
> Can you provide more information about this Adhoc-demo mode? I have
> never heard of it.
>
> --
> Kalle Valo
>

Re: Adhoc-demo support in mac80211

[Johannes Berg]

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On Tue, 2009-03-24 at 16:48 -0400, ming li wrote:

> The adhoc-demo mode is also called pseudo-adhoc mode. It is simply the
> ad-hoc mode without control pkts. It does not probe for or associate
> to adjacent adhoc networks. The user has to set all the nodes to the
> same channel manually. The good thing of adhoc-demo is that it does
> not have the beaconing overhead or the IBSS merging/splitting problem.

Do you really need to disable beaconing, or would it be sufficient for
you to just fix the BSSID and the channel? You can do those two already
easily, something like
	iwconfig wlan0 ap ...
	iwconfig wlan0 channel ...

johannes

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Re: Adhoc-demo support in mac80211

[ming li]

Yes, I have to disable beaconing. Is there any easy way to disable
them? Will this confuse the state machine in mac80211?

BTW, even if you do "iwconfig wlan0 ap..." the IBSS domain still might
split when the link loss rate is high, right?

On Tue, Mar 24, 2009 at 4:53 PM, Johannes Berg
<johannes@sipsolutions.net> wrote:
> On Tue, 2009-03-24 at 16:48 -0400, ming li wrote:
>
>> The adhoc-demo mode is also called pseudo-adhoc mode. It is simply t=
he
>> ad-hoc mode without control pkts. It does not probe for or associate
>> to adjacent adhoc networks. The user has to set all the nodes to the
>> same channel manually. The good thing of adhoc-demo is that it does
>> not have the beaconing overhead or the IBSS merging/splitting proble=
m.
>
> Do you really need to disable beaconing, or would it be sufficient fo=
r
> you to just fix the BSSID and the channel? You can do those two alrea=
dy
> easily, something like
> =A0 =A0 =A0 =A0iwconfig wlan0 ap ...
> =A0 =A0 =A0 =A0iwconfig wlan0 channel ...
>
> johannes
>
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Re: Adhoc-demo support in mac80211

[Alina Friedrichsen]

Hi!

> BTW, even if you do "iwconfig wlan0 ap..." the IBSS domain still migh=
t
> split when the link loss rate is high, right?

No, the BSSID is fixed for ever. I have implement it.

Regards
Alina

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Re: Adhoc-demo support in mac80211

[Johannes Berg]

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On Tue, 2009-03-24 at 16:58 -0400, ming li wrote:
> Yes, I have to disable beaconing. Is there any easy way to disable
> them? Will this confuse the state machine in mac80211?

Not really, it should work, with the expected problems.

I'm not going to support it in mac80211 though -- so you're going to
rely on a patch to the kernel forever forward.

johannes

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Re: Adhoc-demo support in mac80211

[Alina Friedrichsen]

Hello Ming!

> The good thing of adhoc-demo is that it does
> not have the beaconing overhead or=20

I personally don't like the idea implementing this non-standard mode in=
 mac80211 as a separate mode, but maybe allow the user to disable beaco=
ning with a nl80211 call?

Johannes, what do you think about it?

> the IBSS merging/splitting problem.

With mac80211 you can set a fixed BSSID like with madwifi to solve this=
 Problem.

iwconfig wlan0 ap 42:ca:ff:ee:fe:ed

Regards
Alina

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