Just wanted to share my experience:

My PowerBook G4 1.5 15" (SMS/BT2 - Al) doesn't play nice with my Ubee EVW 3200 modem/router. It connects to it, it connects to the internet...but the internet connection dies at random (though the connection to the modem/router + other local connections stay alive). The only way to regain a connection to the internet is to either kill netstack and loading it again (but this makes the system very unstable ;) or rebooting.

Tried about every configuration, on MorphOS and the modem/router, but to no avail. In the end, the solution was to connect an old Netgear N150 router to the Ubee modem/router (piggyback) and connect the PowerBook to the Netgear's signal. Now the internet connection is stable.