ISO is an organization. OSI is a model.
Edit: there are also definitely more than four “layers” (standard handoff points).
- Physical involves the media and transmission format (e.g. EMF, waveform, etc)
- data link involves multiplexing and addressing on the local segment
- Network involves beyond-segment addressing
- Transport involves standard endpoint communication methods (tcp/udp)
Are you implying this is where everything ends?
What about application level multiplexing (sockets)?

And frost, because it’s the only one I like. If I like it, it’s frost.