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

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

[Breno Jacinto]

Hello everyone,

  I`m running several experiments involving ad hoc networks. I`ve
selected some well known-to-be-compatible adapters, such as Edimax
(Ralink shipset), Alfa networks (Realtek) and Atheros (madwifi).
Atheros is available only as built-in adapter on the equipement or as
a  PCI board.

  So, I'm experiencing some instability regarding the selection of
the BSSID used by all the nodes. I start the network with a single
node, then another, then another. Now, for a couple of minutes it
works, bu then some nodes start losing sight of each and changing
their BSSIDs to a different value (and they should always use the
same). I'm really running out of
explanations of why this is happening, because these nodes are all
in-range of each other, and should be "pingable" directly. My main
suspect is the driver instability, but then I dont know of any other
better alternatives. I've tested the following USB adapters:

- Edimax EW-7318USg (rt73 drivers)
- Alfa AWUS036H-11g

  And the builtin adapters:

- Atheros chipset AR5007EG


best regards,

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

[Simon Wunderlich]

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Hey Breno,

sounds like the well known ad-hoc cell splitting problem to me. A common
workaround is to fixate the BSSID to some pre-defined value:

iwconfig athX ap 02:CA:FF:EE:BA:BE

hopefully all your drivers support this. :)

best regards,
	Simon

On Wed, Feb 04, 2009 at 03:03:35PM -0300, Breno Jacinto wrote:
> Hello everyone,
> 
>   I`m running several experiments involving ad hoc networks. I`ve
> selected some well known-to-be-compatible adapters, such as Edimax
> (Ralink shipset), Alfa networks (Realtek) and Atheros (madwifi).
> Atheros is available only as built-in adapter on the equipement or as
> a  PCI board.
> 
>   So, I'm experiencing some instability regarding the selection of
> the BSSID used by all the nodes. I start the network with a single
> node, then another, then another. Now, for a couple of minutes it
> works, bu then some nodes start losing sight of each and changing
> their BSSIDs to a different value (and they should always use the
> same). I'm really running out of
> explanations of why this is happening, because these nodes are all
> in-range of each other, and should be "pingable" directly. My main
> suspect is the driver instability, but then I dont know of any other
> better alternatives. I've tested the following USB adapters:
> 
> - Edimax EW-7318USg (rt73 drivers)
> - Alfa AWUS036H-11g
> 
>   And the builtin adapters:
> 
> - Atheros chipset AR5007EG
> 
> 
> best regards,
> 
> -- 
> -- 
> :: Breno Jacinto ::
> :: breno - at - gprt.ufpe.br ::
> :: FingerPrint ::
>    2F15 8A61 F566 E442 8581
>    E3C0 EFF4 E202 74B7 7484
> :: Persistir no difícil é a única maneira de torná-lo fácil algum dia.  ::
> _______________________________________________
> B.A.T.M.A.N mailing list
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> 

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

[Breno Jacinto]

Hello Simon,

    Thanks, I was searching a bit on google about that. It's harder to
solve than I thought.

     I still wonder if setting up a static BSSID will stop the BSSID
selection algorithm from ocurring. What do you think? Have tested this
in practice?

    Setting the BSSID manually was only supported by the Atheros
chipset, which runs on my laptop. I'm also working with portable
devices, such as OpenMoko Freerunner (which is Atheros too, but I
havent checked this) and Nokia N810 (which has a prism chipset). Nokia
N810 was really buggy... whenever I tried to put one device on the
network, it started to split itself from it.

best regards,

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2009/2/4 Simon Wunderlich <simon.wunderlich@s2003.tu-chemnitz.de>:
> Hey Breno,
>
> sounds like the well known ad-hoc cell splitting problem to me. A common
> workaround is to fixate the BSSID to some pre-defined value:
>
> iwconfig athX ap 02:CA:FF:EE:BA:BE
>
> hopefully all your drivers support this. :)
>
> best regards,
>        Simon
>
> On Wed, Feb 04, 2009 at 03:03:35PM -0300, Breno Jacinto wrote:
>> Hello everyone,
>>
>>   I`m running several experiments involving ad hoc networks. I`ve
>> selected some well known-to-be-compatible adapters, such as Edimax
>> (Ralink shipset), Alfa networks (Realtek) and Atheros (madwifi).
>> Atheros is available only as built-in adapter on the equipement or as
>> a  PCI board.
>>
>>   So, I'm experiencing some instability regarding the selection of
>> the BSSID used by all the nodes. I start the network with a single
>> node, then another, then another. Now, for a couple of minutes it
>> works, bu then some nodes start losing sight of each and changing
>> their BSSIDs to a different value (and they should always use the
>> same). I'm really running out of
>> explanations of why this is happening, because these nodes are all
>> in-range of each other, and should be "pingable" directly. My main
>> suspect is the driver instability, but then I dont know of any other
>> better alternatives. I've tested the following USB adapters:
>>
>> - Edimax EW-7318USg (rt73 drivers)
>> - Alfa AWUS036H-11g
>>
>>   And the builtin adapters:
>>
>> - Atheros chipset AR5007EG
>>
>>
>> best regards,
>>
>> --
>> --
>> :: Breno Jacinto ::
>> :: breno - at - gprt.ufpe.br ::
>> :: FingerPrint ::
>>    2F15 8A61 F566 E442 8581
>>    E3C0 EFF4 E202 74B7 7484
>> :: Persistir no difícil é a única maneira de torná-lo fácil algum dia.  ::
>> _______________________________________________
>> B.A.T.M.A.N mailing list
>> B.A.T.M.A.N@open-mesh.net
>> https://lists.open-mesh.net/mm/listinfo/b.a.t.m.a.n
>>
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>
>

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

[Marek Lindner]

Hi,

>      I still wonder if setting up a static BSSID will stop the BSSID
> selection algorithm from ocurring. What do you think? Have tested this
> in practice?

yes, it will deactivate the selection algorithm. We used this hack to get the 
Freifunk Berlin network stable. We had a real hardware zoo (Atheros, Broadcom, 
Ralink, etc) that was impossible to control without setting the BSSID.

Regards,
Marek

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

[Breno Jacinto]

Hello Marek,

   Have you managed to set a static BSSID to all those chipsets -
Atheros, Broadcom, Ralink etc? Because up to now, only Atheros made
this trick possible.

   If I managed to do that with the rt73 chipset that would be enough.
But the driver guys seem to have no documentation stating if this is
possible or not, and doing an iwconfig rausb0 ap <BSSID MAC> does not
change anything :/.

best regards,

2009/2/5 Marek Lindner <lindner_marek@yahoo.de>:
>
> Hi,
>
>>      I still wonder if setting up a static BSSID will stop the BSSID
>> selection algorithm from ocurring. What do you think? Have tested this
>> in practice?
>
> yes, it will deactivate the selection algorithm. We used this hack to get the
> Freifunk Berlin network stable. We had a real hardware zoo (Atheros, Broadcom,
> Ralink, etc) that was impossible to control without setting the BSSID.
>
> Regards,
> Marek
>
> _______________________________________________
> B.A.T.M.A.N mailing list
> B.A.T.M.A.N@open-mesh.net
> https://lists.open-mesh.net/mm/listinfo/b.a.t.m.a.n
>



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

[Marek Lindner]

Hi,

>    Have you managed to set a static BSSID to all those chipsets -
> Atheros, Broadcom, Ralink etc? Because up to now, only Atheros made
> this trick possible.

thanks to Felix from the OpenWRT project the Atheros driver has that feature 
(as you know). Broadcom is a much harder cases because the drivers a binary 
only. We mostly use the famous WRT54G and its derivates for our network. Sven-
Ola managed to write patch for that binary driver of the WRT. There also is an 
open source driver project for the broadcom chips but I'm not sure where it 
stands.
I never experimented with Ralink myself, so I can't answer that. I'm sure 
Elektra could jump in here.  :-)

Regards,
Marek

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

[Breno Jacinto]

Hello Marek,

    Thank you for replying. I have one final question about this.

2009/2/6 Marek Lindner <lindner_marek@yahoo.de>:
> thanks to Felix from the OpenWRT project the Atheros driver has that feature
> (as you know). Broadcom is a much harder cases because the drivers a binary
> only. We mostly use the famous WRT54G and its derivates for our network. Sven-
> Ola managed to write patch for that binary driver of the WRT. There also is an
> open source driver project for the broadcom chips but I'm not sure where it
> stands.

    How about in the laptops / pcs that access the WRT54G, which make
the "infrastructure" of the mesh? What kind of adapters do you use on
them?

> I never experimented with Ralink myself, so I can't answer that. I'm sure
> Elektra could jump in here.  :-)

     That would be really helpful - I'm trying to contact the rt73
drivers guys for the last week and got no response from them. If
anyone could confirm whether these Edimax dongles could set a static
BSSID, that would help us decide which equipment to buy for building
our ad hoc network test-bed.

> Regards,
> Marek

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

[elektra]

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

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

[Breno Jacinto]

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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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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>

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

[Marek Lindner]

Hi,

>     How about in the laptops / pcs that access the WRT54G, which make
> the "infrastructure" of the mesh? What kind of adapters do you use on
> them?

I think Elektra made clear that the driver situation for mobile devices is 
much worse. We stopped promoting laptops as part of the network. Next to the 
driver issues we faced different OSes in different versions, firewalls, 
$security_software, wrongly configured routing daemons, confused ordinary 
users, etc. Instead we encouraged people to use the routers for meshing and 
normal managed networks for the laptops.

Regards,
Marek

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

[Marek Lindner]

Hi,

>      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).

although the Openmoko Freerunner has an Atheros chip inside it does not use 
the madiwifi driver (this is the AR6001 mobile chip, in case you wonder).


>      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 (?).

AHdemo is not the same as setting the BSSID in ad-hoc mode manually. As 
mentioned on the page you linked to the AHdemo mode does not send any beacons. 
Whereas the ad-hoc mode sends beacons with a fixed BSSID. Not sending beacons 
has certain side effects: 
- your network will appear being "invisible" (the normal network manager wont 
show it)
- you have to manually configure the connection speed and other stuff as the 
usual autonegotiation is using the beacons for that
- you will have collisions (might lead to decreased performance)
- driver compat problems (only a few drivers support this mode)

Nevertheless, it will fix your cell split problem. :-)


>      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?

I think EEE PC uses the madwifi driver?! If so you can set the BSSID 
statically.

Regards,
Marek

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

[elektra]

Hi -

some EEE PC models use a Atheros mPCI wireless card (the 701 for example) but 
my 901 was shipped with a Ralink rt2870 (802.11 abgn) that I replaced with an 
Atheros abg card ASAP...

Actually I'm using Ahdemo mode in my EEE-PC which works nicely together with 
other devices with 'normal' IBSS-mode but fixed IBSS-ID - in our local mesh 
we use Madwifi with OpenWRT patches and Broadcom-based devices (WRT54G/GL/GS, 
Asus WL500GP) with OpenWRT Whiterussian and Broadcom proprietary driver with 
fixed IBSS-ID hack (Freifunk Firmware).

Rate adaption with the Ministrel algorithm works well in Ahdemo mode - and you 
have the possibility to set up a AP VAP on the same interface, too.

Performance is fine. That may be different if you run a Ahdemo-only network in 
range with other wireless networks - they won't detect collisions, hence 
performance can suffer.

Cheers,
elektra

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

[Breno Jacinto]

Hello Marek, Elektra,

    Thank you very much for the information.

    By the way, I think you guys are involved on that book project
about community wireless networks, hosted at WNDW.net. I'm from
Brazil, and I have noticed that the only translation available is to
the first edition, but the book seems to be on its thrid edition
actually.

    I'd be interested to cooperate on the translation of the book, as
I intend to use them on my classes and also I intend to start some
community network projects where I live. Do you know who should I
contact in order to help on the translation?


regards,

2009/2/8 elektra <onelektra@gmx.net>:
> Hi -
>
> some EEE PC models use a Atheros mPCI wireless card (the 701 for example) but
> my 901 was shipped with a Ralink rt2870 (802.11 abgn) that I replaced with an
> Atheros abg card ASAP...
>
> Actually I'm using Ahdemo mode in my EEE-PC which works nicely together with
> other devices with 'normal' IBSS-mode but fixed IBSS-ID - in our local mesh
> we use Madwifi with OpenWRT patches and Broadcom-based devices (WRT54G/GL/GS,
> Asus WL500GP) with OpenWRT Whiterussian and Broadcom proprietary driver with
> fixed IBSS-ID hack (Freifunk Firmware).
>
> Rate adaption with the Ministrel algorithm works well in Ahdemo mode - and you
> have the possibility to set up a AP VAP on the same interface, too.
>
> Performance is fine. That may be different if you run a Ahdemo-only network in
> range with other wireless networks - they won't detect collisions, hence
> performance can suffer.
>
> Cheers,
> elektra
>
>
>
> _______________________________________________
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>



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[B.A.T.M.A.N.] WNDW

[elektra]

Hi Breno -

thank you for your interest in supporting WNDW translations. Please keep 
in mind that this is off-topic for the Batman list.  I'd like to 
redirect you directly to the forums of the WNDW page: 
http://forums.wndw.net/ The main editor of the English WNDW book and 
maintainer of the WNDW web site is Rob Flickenger.

Cheers,
elektra