How connect 2 PC with ath in hostap mode ?

Sten Daniel Sørsdal lists at
Sun Oct 9 18:05:27 PDT 2005

Marcin Jessa wrote:
> On Tue, 4 Oct 2005 16:37:21 +0400
> Andrey Smagin <samspeedu at> wrote:
>>Hello Marcin,
>>Tuesday, October 4, 2005, 11:35:17 AM, you wrote:
>>MJ> How are you bridging the interfaces? What kind of bridging
>>MJ> mechanism are you using?
>> In FreeBSD:
>>  kldload ath, ath_hal, bridge, fxp
> Recompile your kernel with following options.
> device          wlan                    # 802.11 support
> device          ath
> device          ath_hal
> device          ath_rate_sample
>>On both host:
>>  ifconfig_ath0="inet ssid 1234 channel 6 mode 11g mediaopt adhoc"
>>in sysctl.conf
>>  hw....bridge.config=ath0:1,fxp0:1
>>  hw....bridge.enable=1
>>  ipfw allow ip from any to any
>>in this mode speed about 8KBy/s
> Try to use if_bridge instead
> ifconfig bridge0 create up
> ifconfig bridge0 addm ath0 fxp0 
> etc...
> The "old" bridge code is removed from CURRENT anyway.
> Try to play with different sysctl values for ath as well, it may or may
> not have an impact on your performance.

If you want to be vague, why not add a disclaimer to your e-mails?

>>  ifconfig_ath0="inet ssid 1234 channel 6 media OFDM54 mode 11g
>>mediaopt adhoc" increase speed up to 45-50 KBy/s
> Right, still pretty little.  You should get between 2-7 MB/s

Stating the obvious?

>>Bridging work fine and uptime for both host more
>>wheek under full load :) (40KBy/s over wireless)
>>Some strange - ping report low average delay about
>>0.700ms for any host in another net segment.
> Try to adjust values of ACK timing, I have made a table with some
> proposed values:

Taking credit for other peoples work again? Appended and attached is an
e-mail from the authors of the ack timings. They wished to relay to you
that you have copied the mikrotik routeros documentation without consent
and thus potentially violated the copyright.


>>MJ> I am not sure why you have such a speed loss running in adhoc
>>MJ> mode. What I noticed on NetBSD (where the ath driver is not yet
>>MJ> fully ported) was I got pretty decent speed with the same setup
>>MJ> as yours (2xath in adhoc bridged with wired nics) but my embedded
>>MJ> devices allways crashed when I sent over many small packets.
>>  I think this is a driver problem, two ap sucessfully connect
>>with each other, why hostap can't do this ? 

Because it would require WDS or other extension to the standard.

> That's becouse FreeBSD ath hostap is for access points , not for
> interaction between two APs.

FreeBSD ath hostap is for AP's not for interaction between AP's?
Where were you going with that, exactly?


> Did you run tcpdump on both the hosts to find out what may be causing
> your problems?
>  I will test adhoc between two atheros boxes at home
> today. 

Did your "atheros boxes" perform any better?

---------------------------[ Appended e-mail ]--------------------------
Subject: [Ticket#: 2005100716000313] [Fwd: Re: How connect 2 PC with ath
in hosta [...]
From: "MikroTik Support [Dmitry]" <support at>
Date: Fri, 07 Oct 2005 17:09:55 +0300
To: Sten Daniel Sørsdal <list at>


The first table I've got from our developers, and I really have no idea
where did it come from, the available frequencies table is freely
accessible via RouterOS console and also may be obtained from atheros
cards' eeprom. But the second one (that about ACK times) is authored
here. Me and one my collegue have invested much time into making this
table and his claims can be considered as copyright violation. I am sure
he can not provide any proof of his authorship, but I still have few
pieces of paper with some weird formulae lost somewhere on my table.
Thank you for pointing out this issue, can you also write back to the
list for me?


Sten Daniel Sørsdal <list at> wrote:

>> Apologies for the inconvenience but on the freebsd-net at
>> mailing list there is a guy that claims he wrote the tables
>> found here
>> (
>> Which are identical (aside from font formatting) to the ones
>> found here:
>> (
>> Who's material is it?
>> --
>> Sten Daniel Sørsdal

Sten Daniel Sørsdal
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