(ok I don't actually know what the "mb" stands for but it appears in the dji_mb_ctrl utility on some drones)
This protocol, also known as DUML, is used by most DJI components to communicate with each other, including the mobile app and DJI Assistant. It is easily recognizable by the byte 0x55 at the start of each packet (often 0x55 0x?? 0x04 ...).
The Wireshark Dissector represents the current state of what is publicly known about this protocol.
Routing tables can be found on the aircraft and remote control at /system/etc/dji.json.