This document on European Telecommunications Standards Institute website describes some Machine2Machine (M2M) communications protocols. I've seen
dIa interfaces in some research papers, however, this document, which seems to be one of the only few useful resources in describing what they are does not seem to throw much light on them.
What are these interfaces and where is the M2M communication normally used? I'm very new to these terms. I'm familiar with Computer Networking in terms of the five OSI layers. I would appreciate if someone can throw some light on these interfaces.