Hi,
MC7304 does not support DirectIP, it uses a different protocol RMNet, you do not need to worry about this if you build the GobiSerial and GobiNet drivers into your system as per the note, it to all intents and pruposes looks like DirectIP.
Assuming the unit is in the default config when it enumerates to the system you will three /dev/ttyUSB, two /dev/qcqmi and two corresponding eth interfaces (run ifconfig). When you start the data session up the data will be routed through one of these, depending on how your systemis setup (whether you have network manager running or not) depends on whether you will need to send ‘dhclient xxx’ to populate the interface fields. At this point you just use the LTE connection as an Ethernet interface just like with DirectIP.
Regards
Matt