Strange sniffer result for "iwconfig wlan0 channel" and "iwconfig wlan0 AP"

[张 yf]

Dear ALL:

Today I got a strange sniffer result.the testbed as follows(APs and 
terminal all is driven with hostap driver 0.3.7) :
AP 1 works channel 1 and its mac address is ap1_MAC; AP 2 works channel 6 
and its mac address is ap2_mac; AP1 and AP2 serve the same ESSID "TEST".Sta 
1 configure its ESSID as "TEST", Channel as any. After sta 1 is up, it will 
associate with AP1, and works in channel1, then I run the command "iwconfig 
wlan0 channel 6", strange result comes out:

The sta1 deauthenticates with the AP1, and begins to send probe request on 
both channel 1 and channel 6 (maybe other channels), but then sometime it 
will send out associate request on channel 6 with the ap2_mac ( I think 
that is right), sometime it will sent out associate request with the 
ap1_mac(of couse wrong, for ap1 works on channel 1), sometime it will send 
out associate request on channel 1 with ap1_mac (then still associate with 
ap1).

After "iwconfig wlan0 channel 6", most time the sta1 still associates with 
AP1 on channels, and only in very little case, it will associate with AP2 
on channel 6.

Then I run "iwconfig wlan0 AP AP_mac", any message can't be catch by the 
sniffer.

Any one can explain this to me? is it a bug for the driver? how can I 
overcome it?

I will appreciate your any suggestion.

Thanks and Regards

Leonard Zhang

_________________________________________________________________
???? MSN Explorer:   http://explorer.msn.com/lccn/