wireless adapter fails to associate only with some networks
 

Hi,

Question for all you wireless networking experts out there: I have been using wireless networks for some time now, (> 1 year) at my University, but when I try to use a city-wide commercial network, it fails to associate. When I do iwlist, I see the commercial network, with multiple APs. The link quality is comparable to the campus network that I've been using, there is no encryption, and I can see the beacons and get multiple AP MAC addresses.

How do I make iwconfig or any other config tool tell me why eth1 is failing to associate with the commercial network? Am I getting rejected? Is there another dimension to link quality that the "link quality" metric doesn't tell me?

The campus network is called "tsunami", and the commercial one is called "merr.com" Here is some sample output:


root@explosive-c:/home/hinrichs# iwconfig eth1 essid tsunami
root@explosive-c:/home/hinrichs# iwconfig eth1
eth1 IEEE 802.11g ESSID:"tsunami"
Mode:Managed Frequency:2.412 GHz Access Point: 00:13:19:64:65:70
Bit Rate=54 Mb/s Tx-Power=20 dBm Sensitivity=8/0
Retry limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=46/100 Signal level=-73 dBm Noise level=-82 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:37 Missed beacon:0


-- Here is a selection of results from iwlist eth1. Note that the link quality on the tsunami AP that I am using is 37/100:

Cell 01 - Address: 00:13:19:64:65:70
ESSID:"tsunami"
Protocol:IEEE 802.11bg
Mode:Master
Channel:1
Encryption key:off
Bit Rates:54 Mb/s
Extra: Rates (Mb/s): 1 2 5.5 6 9 11 12 18 24 36 48 54
Quality=37/100 Signal level=-78 dBm
Extra: Last beacon: 3560ms ago

Cell 20 - Address: 00:0B:85:70:FB:0C
ESSID:"merr.com"
Protocol:IEEE 802.11bg
Mode:Master
Channel:1
Encryption key:off
Bit Rates:54 Mb/s
Extra: Rates (Mb/s): 1 2 5.5 11 6 9 12 18 24 36 48 54
Quality=37/100 Signal level=-78 dBm
Extra: Last beacon: 1264ms ago


Cell 23 - Address: 00:0B:85:66:6E:7C
ESSID:"merr.com"
Protocol:IEEE 802.11bg
Mode:Master
Channel:11
Encryption key:off
Bit Rates:54 Mb/s
Extra: Rates (Mb/s): 1 2 5.5 11 6 9 12 18 24 36 48 54
Quality=41/100 Signal level=-76 dBm
Extra: Last beacon: 5772ms ago


Cell 27 - Address: 00:0B:85:71:09:8C
ESSID:"merr.com"
Protocol:IEEE 802.11bg
Mode:Master
Channel:6
Encryption key:off
Bit Rates:54 Mb/s
Extra: Rates (Mb/s): 1 2 5.5 11 6 9 12 18 24 36 48 54
Quality=33/100 Signal level=-80 dBm
Extra: Last beacon: 396ms ago


root@explosive-c:/home/hinrichs# iwconfig eth1 essid merr.com
root@explosive-c:/home/hinrichs# iwconfig eth1
eth1 unassociated ESSID:"merr.com"
Mode:Managed Frequency=2.412 GHz Access Point: Not-Associated
Bit Rate=0 kb/s Tx-Power=20 dBm Sensitivity=8/0
Retry limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:37 Missed beacon:0

root@explosive-c:/home/hinrichs# ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:13:CE:F4:55:47
inet6 addr: fe80::213:ceff:fef4:5547/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:132 errors:0 dropped:37 overruns:0 frame:0
TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:943124 (921.0 KiB) TX bytes:145433 (142.0 KiB)
Interrupt:5 Base address:0x8000 Memory:fafef000-fafeffff

defn city-wide
 

How are you defining commercial, city-wide? You may need a different card for the commercial network.

The commercial network is meant to work with any regular 802.11 card, just like using a public library or coffee house network, except that you authenticate through a web page after joining the network.

I got the laptop to associate with the network, (though DHCP fails,) by moving closer to the window, so despite the link quality indicating that the link is usable, it's probably too weak of a signal, and that's what's preventing me from joining.

Chris H.