I've been trying to setup routing of Multicast IPTV to my home network. My gateway PC has a 100 Mbit/s ethernet adapter as external interface and a rt73-based USB dongle as home network interface.
As soon as I enable multicast forwarding to rt73, the wireless connection quickly freezes ping slows down then stops coming through completely, ssh session freezes as well. When I disable multicast forwarding, the connection 'unfreezes' in a few minutes. It looks like the rt73 interface gets overwhelmed with the IPTV packet storm for some reason.
Same setup works fine with the legacy driver.
It's not a support request, since I'm using a different setup now that doesn't involve Multicast routing. It's more of a problem report this does look like a bug in the rt73usb driver.