Hi Benjamin,
Open question would be: Which OSI layers would be in scope here? Is 4-7 enough or would you also see layers 1-3 in the scope?
Do you have specific protocols in mind?
I am not sure there would be a justification to formally limiting the scope to just layer 4 and above. What do you think?
My point here is that you from your M2M background are most likely interested in protocols on a "lower level" than I am from the HA background.
Just to give you an example: For M2M, MQTT is interesting as it provides you the means to transport data from machine to machine. For HA, I don't care how data is transferred, but I am interested in the semantics of the data, i.e. the data that is transported
via MQTT. If the data would be transported through MQ Series, it would just be another transport mechanism, I do not care too much as long as I know that the received data is a temperature value from my backyard.
Another example (as you mentioned HTTP): HTTP is similar to MQTT to me: It is a transport protocol. What matters to me is e.g. the Philips Hue REST API built on top of HTTP: This lets me control devices and get hold of their state.
So the discussion I wanted to spark here is that different people have a very different understanding what a "protocol" actually is - as there are so many layers (=perspectives) to consider :-)
Best regards,
Kai
