I took a networking course in university, taught by a professor who has never touched a router in his life. But it wasn't that bad of a course--it was more of a theory and philosophy of networking course--so if you were expecting to be able to come out of the course knowing how to configure a router, you were probably in the wrong place.

There was one important thing I learned in the course though, and it forever changed how I see the Internet. I see the internet now as an abstraction, or an abstract communications network. It was created so that device or person A could communicated with person or device E, without concern of what networking technologies exist between A and E.

So take something like:

A ---- (PSTN) ----> B ---- (Microwave) ----> C ---- (Ethernet) ----> D ---- (Cable) ----> E

And the Internet does this:

A ---- (Internet) ----> E

The Internet makes end-to-end communication possible, without having to worry about the underlining network technology.