Problems on setting up ad-hoc networks using openmoke phones and X60 laptop (intel IPW3945)

Jun Yi yi_jun_mail at
Thu Aug 28 15:32:30 CEST 2008

 Hi everybody,

      I am planning to set up an ad-hoc network between a lenovo x60 laptop (Fedora 9, update to the newest, IPW3945 802.11ABG, the interface is wlan0 ) and the phone (kernel 2.6.24, freerunner, the wireless interface is eth0). I hacked this problem for two days, and I observed the following anormalities.
      1,  X61 can see the ad hoc cell.  I use iwlist wlan0 scan. The output displays the ad-hoc network cell id (xx:xx:xx---), ssid name (xxxx), and the same frequency, and the encryption is off.  But on the other side,  the phone can not see the ad hoc cell. I use iwlist eth0 scan, the output only shows the cell established by some access points (master mode). I am sure that the setting at the phone is correct (ifconfig eth0 down, iwconfig eth0 mode ad-hoc, essid xxxx, channel xxx, enc off, ifconfig eth0 up). 

     2,  Then I ping X61 from the phone, I use wireshare (a packet sniffer tool, like tcpdump) to sniffer the received packets at X61, I can see X61 received ARP requests from the phone and sent ARP replies back to the phone, but the phone did not get any ARP replies. Therefore the phone continue sending ARP request messages. What's the reason does the phone not receive packets correctly? too noisy?, can not unencrypt packets?

     3, I ping the phone from X61. I observe from tshark that ARP requests are already sent out, but no ARP requests are received at the phone, observing by using tcpdump -i eth0 host, which is the ip address of X61.

     4, at the phone, sometimes the changes of channel (using iwconfig eth0 channel N) can not take effect, no matter how long I wait, even if I use ifconfig eth0 up frequently. The wireless adaptor (AR6000) at the phone always tries to stick to the original one

     5, I can access an access point, and whereby access the internet.

     6, I use iwconfig eth0 to list the status of the phone wireless adaptor. The sensitivity is read 0/3, and the link quality is read sometimes 0/94, and sometimes 100/94. What does that mean? Does that mean the sensitivity threshold is too high, so the wireless adaptor treats signals as noise?  But I tried to set sensitivity (iwconfig eth0 sens NdBm). The output says that the wireless card does not support this operation. 

    7, I check the ouput of all related commands (e.g., /etc/hosts, /etc/resolv.conf, netstat -nr, route).  pretty sure that routing is not a problem.

    Does anybody have the successful experience to setup an ad-hoc network using openmoko phones? I am very frustrated.

    Thanks very much


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