WG v4 2023-09-28

[emiltin]

Participants

David, Emil

MQTT Experiment

We looked at a practical experiment with two small Elixir apps, one that works as a device, and the other working as a supervisor.

This demonstrated:

• how MQTT can be used in an Elixir app
• how they they can connect to an MQTT broker (we used EMQX running in a docker container).
• how online/offline status of device can be send to the supervisor, and how this can be retained on the broker, so that the supervisor gets the online/offline status immediately once reconnecting
• how the supervisor can send a command to the device, and get a response back to that particular command, based on using Response-Topic and Correlation-Data.

Next steps

We have looked how MQTT would fit with RSMP, and we're rather positive. What other questions should be consider before we can provide a recommendation aorund RSMP 4 on MQTT?

• bandwidth. how can we compare with rsmp 3?
• what tools are available for experimenting and testing?
• what MQTT libraries exist that supplier could use in implementations and how mature are they?
• security, TLS, etc?
• how much extra complexity does a broker add?
• why do we need rsmp 4?