Agreed, distinction will always be vague.
If we are forced to put structure around it though, I think that framework is reasonable, despite its flaws.
Yeah, it just gets out of date as people keep stacking more things on top of what was previously called "application" as they interop them and the upper layers of the cake get more and more indistinguishable.
I think that really, even TCP/IP, as a network layer, is an application. How can you say that netcat is not an application? Or telnet, both of which sit directly above TCP/IP. Indeed, TCP is on top of IP, in fact, it's an application for reliable message transport. The network itself is an application!
Anyhow, la la la la so boring the grandstanding of academics who didn't invent the protocols to make pronouncements about other people's work.
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