I have a question about Non-IP device communication.
From my research, I learnt CoAP and DDS can be used for Device-to-Device communication.
MQTT is useful for Device-to-Gateway or Device-to-Service or Cloud.
My question is, how can a non-IP device (communicating over a simple RF or Bluetooth, etc.. without IP) use these protocols?
MQTT uses TCP/IP
COAP, DDS, MQTT-SN use UDP/IP
So that means they use IP. How is this possible? Are there other protocols that do not use TCP or UDP for D2D and Device-to-Gateway?