Hello Haiko,
I have seen the same "Device Offline" behaviour on a customer switching and wireless network.
After we restarted ALL the switches the problem "went away" but not before we had broadcast storms from the switching taking down our 3rd party firewall.
I am a bit suspicious of the failure of the switching to stop any broadcast storm. Have you tried rebooting all your downstream switching???
I logged a ticket but the response was "it works better when setup for local management".
Not what I wanted to hear.
Kindy, Steph.
------------------------------
Stephan Gladiadis
------------------------------