Comment 43 for bug 291760

I have the same problem using the b43 driver (Jaunty, amd64, all updates until today):

'NetworkManager: <debug> [1239965661.089967] periodic_update(): Roamed from BSSID 00:11:88:FD:03:D3 (HU-VPN) to 00:11:88:27:DA:A3 (HU-VPN)
Apr 17 12:54:44 mm-laptop kernel: [ 184.041206] wlan0: authenticate with AP 00:11:88:5a:2a:43
Apr 17 12:54:44 mm-laptop kernel: [ 184.042989] wlan0: authenticated
Apr 17 12:54:44 mm-laptop kernel: [ 184.042996] wlan0: associate with AP 00:11:88:5a:2a:43
Apr 17 12:54:44 mm-laptop kernel: [ 184.045958] wlan0: RX ReassocResp from 00:11:88:5a:2a:43 (capab=0x401 status=0 aid=34)
Apr 17 12:54:44 mm-laptop kernel: [ 184.045965] wlan0: associated
Apr 17 12:54:46 mm-laptop NetworkManager: <debug> [1239965686.001293] periodic_update(): Roamed from BSSID 00:11:88:27:DA:A3 (HU-VPN) to 00:11:88:5A:2A:43 (HU-VPN)
Apr 17 12:55:22 mm-laptop NetworkManager: <debug> [1239965722.000802] periodic_update(): Roamed from BSSID 00:11:88:5A:2A:43 (HU-VPN) to (none) ((none))'

For me, this happens only in a big hall of my university's library where I see about 15 APs with 3 different Essids. In some corners the connection is stable, in some not. Using the same network in places where there is only one AP, the connection is stable. I had some conversation with the admin about this. He said, I am the first person to complain, though a friend also using Ubuntu has instabilities as well. So other operating systems seem to work better with that network. The admin also told me, that there are some APs with 'strange' behaviour in that network, and indeed, I see this 'roamded to (none) ((none))' more often on some and less often on others.
Killing all instances of NetworkManager and connecting manually solves this. Maybe I should add that this is an unprotected network in combination with VPN.