Re: [B.A.T.M.A.N.] Stable adapters for Ad Hoc networks

Breno Jacinto
2009-02-07T22:44:56Z

Hello Elektra,

Thanks for the information. At least now I have some background
to work on - I already have several rt73 USB dongles, some notebooks
with Atheros, some OpenMokos (which have atheros chipsets) and a few
Nokia N810 tablets (which have a prism chipset). Specially the Nokias
are actually messing up the network, when I put them together. They
just dont seem to figure out how to syncronize to the same BSSID.
These devices are all on the same room, in close range.

I read this
http://wiki.villagetelco.org/index.php/Information_about_cell-id_splitting,_stuck_beacons,_and_failed_IBSS_merges!

And they mentioned about some intermediate mode, called
Pseudo-IBSS or AHdemo mode, which allows a device to set a static
BSSID and it is supported by some drivers. I suppose we are talking
about the same thing here, just not giving any names (?).

When you mentioned your EEE PC, which uses an Atheros chipset,
did you also had to set a static BSSID to the same used in the mesh
network you use?

regards,

--
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:: Breno Jacinto ::
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2009/2/7 elektra <onelektra@gmx.net>:
> Hi -
>
> I'm waiting for working drivers (particularly USB) for IBSS mode for long
> time and was putting my hope on Ralink RT73 as well.
>
> The situation is improving with the mac80211 driver development in the Linux
> kernel. Recently patches went into compat-wireless that allow to fix the
> IBSSID with the
>
> iwconfig <interface> ap <cell-id>
>
> command - with some drivers, not all.
>
> However the situation is a little more complex than just fixing the IBSSID,
> because the drivers/firmware have to be convinced not to perform a IBSS-merge
> every time the TSF timestamp in a received beacon is a little older. Upon a
> merge the cards may flush their MAC table - this could happen every few
> miliseconds - like I have observed with Intel ipw4965 driver. Also TSF clock
> skews can cause race conditions.
>
> So far ath5k and ath9k seem to work - but the only driver I can really
> recommend is Madwifi with all patches from Openwrt - vanilla Madwifi is
> *not* working. The patched Madwifi in Openwrt Kamikaze works perfectly (I'm
> using mesh with Batman exclusively every day and I can suspend/resume my
> EEE-PC for weeks and I'm always online ;-)
>
> But Madwifi does not support USB...
>
> Best bet for USB is Zydas, I guess.
>
> cu elektra
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