documentation
JoinEUI
When you introduce a new JoinEUI, use the manufacturer’s OUI for the first bytes of the JoinEUI. Consider separate JoinEUIs per frequency band or per brand. There is no problem having multiple JoinEUIs point to the same join server. Do not create a unique JoinEUI per device and do not use a random sequence. If an OUI is not available, use all zeros to indicate that a join server is not available. The intention is to consolidate devices.