It's good, but... I wish it were more critical? Excluding the gross control plain (as it wasn't the focus), there's some awkward overlap between IP and Ethernet (link aspects).
My guess, that I'd love to see explicitly confirmed, is that it goes back to the internet as the internetwork—lingua franca between existing networks an idea predating the more technically-motivated concept of layed protocols providing compounding abstractions.
I don't want to sound like a nit of an otherwise great piece, but without criticism the history seems inevitable. Alternatives and hypotheticals are good to keep design space from atrophing in the face of collective amnesia.
My guess, that I'd love to see explicitly confirmed, is that it goes back to the internet as the internetwork—lingua franca between existing networks an idea predating the more technically-motivated concept of layed protocols providing compounding abstractions.
I don't want to sound like a nit of an otherwise great piece, but without criticism the history seems inevitable. Alternatives and hypotheticals are good to keep design space from atrophing in the face of collective amnesia.