R: [Voyage-linux] How to realize a Point to Point Connection

Mon Feb 6 21:08:26 HKT 2006

Thank you Andrew and Punky,

   I made the first links using one wrap in Master mode with 802.11g, in
this mode I can successfully connect to the AP with my laptop getting up to
24 Mbps of ftp transfer rate. 

Then I have switched two Wraps in Ad-Hoc mode and 802.11a giving the same
SSID to both the Wrap and then I have tried a link within few meters. I have
connected a PC via eth0 to each Wrap, then I tried to exchange IP traffic
between the PCs. I can exchange IP traffic between the two clients but at
very low speed < 1 Mbps and with iwconfig "saying" that the speed was 0
kbps.

Maybe it’s an IP configuration problem. 

I use the following IP configuration for both the clients of the bridge,
this is the interfaces file for one client:

auto eth0

iface eth0 inet static

      address 192.168.2.11

      netmask     255.255.255.0

auto ath0

iface ath0 inet static

        address 192.168.2.1

        netmask 255.255.255.0

        broadcast 192.168.2.255        

      up iwconfig ath0 essid VOYAGEM mode Ad-Hoc

      up nat.sh ath0 eth0 "192.168.2.0/24"

Then I have created a script file inserted in the if-up.d directory:

iwpriv ath0 mode 1

iwconfig ath0 enc off

#Bridge
brctl addbr br0
brctl addif br0 eth0
brctl addif br0 ath0
ifconfig br0 192.168.2.21 netmask 255.255.255.0
ifconfig br0 up
#End Bridge

The IP configuration was the following:

Client1                       Client2

ath0: 192.168.2.1             ath0:192.168.2.2

eht0: 192.168.2.11            eht0:192.168.2.12

br0: 192.168.2.21             br0: 192.168.2.22

PC: 192.168.2.31              PC: 192.168.2.32

I haven’t used route rules because surprisingly the two PCs could see each
other without any route rule. It’s seems a little strange, I haven’t fully
understood why.

Looking at the Andrew example I have understood that it’s not necessary to
assign an IP to the ath0 and eth0 when they are bridged, is it correct? 

Thanks for the advices.

Tommaso

-----Messaggio originale-----
Da: Punky Tse [mailto:punkytse at punknix.com] 
Inviato: lunedì 6 febbraio 2006 6.01
A: Punky Tse
Cc: Tommaso; voyage-linux at voyage.hk
Oggetto: Re: [Voyage-linux] How to realize a Point to Point Connection

Tommaso,

I got your meaning wrong...  I thought you are talking about long 

distance link.

What mode (a/b/g) do you run master mode before and what mode for 

Ad-hoc?  It sounds like you set 11b/g mode in master and then switch to 

11a for ad-hoc?   If using 11a, does the antenna support 5 GHz?

The one of the difference betweeen pre1 nad pre3 is madwifi driver.  

pre1 uses madwifi-old while pre3 uses madwifi-ng (r1408).  I had tested 

the madwifi-ng with Ad-hoc and it can even communicate to RM2 (prism54) 

with good throughput in 11b/g mode (e.g. downloading Apple movie 

trailer).  If pre3 makes no difference then its not driver problem.

- Punky

Punky Tse wrote:

> Tommaso,

> 

> It is a tricky for tuning madwifi for long distance link. See:

> 

> http://madwifi.org/wiki/UserDocs/LongDistance

> 

> Punky

> 

> Tommaso wrote:

>> 

>> Hi to all,

>> 

>> I’m actually using the 0.2pre1 version over a Wrap board with one CM9 

>> card. I have no problem having the ath0 interface working in Master 

>> Mode, I get a very good Access Point. Now I’m interested in testing 

>> the possibility to perform long (>5 Km) point to point links. I’m not 

>> a 802.11a-guru, so maybe I’m wrong, but I have put the ath interface 

>> of both clients in Ad-Hoc mode with the same SSID. I get the two 

>> clients connecting each other but with a very very low speed < 1Mps, 

>> the iwconfig reports 0 Kbps even if the received signal is bigger 

>> than -18 dBm (when the two clients are few meters away). I have 

>> changed the radio cards and the antenna, but it definitely seem a 

>> software problem.

>> 

>> It’s a problem of the madwifi driver included in the 0.2pre1?

>> 

>> Tomorrow I will update to the 0.2pre3 version, but I would to know if 

>> the Ad-Hoc mode is the best one for a point to point link; in fact, 

>> reading the madwifi-ng documentation I am a bit confused since you 

>> can use both the Ad-Hoc (iwconfig) mode and the WDS functionality 

>> putting one client in STA mode and the other one in AP mode.

>> 

>> Thanks.

>> 

>> Tommaso

>> 

>> ------------------------------------------------------------------------

>> 

>> _______________________________________________

>> Voyage-linux mailing list

>> Voyage-linux at list.voyage.hk

>> http://list.voyage.hk/mailman/listinfo/voyage-linux

>>   

> 

> 

-- 

Regards,

Punky

P U N K N ! X  . c o m

Technology + Lifestyle

(http://www.punknix.com)

Voyage Linux

(http://www.voyage.hk/software/voyage.html)

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.voyage.hk/pipermail/voyage-linux/attachments/20060206/ae6ec154/attachment-0001.html>