Getting Started with TCP/IP on Packet Radio (1992)
febo.com
febo.com
And it is live in Slovenia and doing great so far. http://nbp.rservis.net/ (click "place NBP markers")
Edit: I just found http://lea.hamradio.si/~s53mv/nbp/rtx.html But can you do it also with off the shelf, hardware?
There is a group buy going on for EATNC kits for 85 euros on a Slovene forum: https://s5tech.net/viewtopic.php?f=57&t=1814&start=0
Non-amateurs probably see this as a way to connect to the internet, while amateurs don't really see that as the point. There will be direct connections in some ways, but the same mindset that makes hardware from the ground up is going to be more interested in creating software stacks from the ground up and making gateways rather than simply using modern internet software on an amateur internet.
"The big one" implies nobody's going to care about licensure or not using the public airwaves for encrypted communications.
Which implies that, if it's less than the big one, the amateurs should have the basic good sense to leave the airwaves to the professionals, and not clutter the frequency bands.
That's pretty unfair. Amateurs often help out with communications after natural disasters, and historically have often been the first to setup radio communication in areas struck by natural disasters.
Situations were HAM operators can get packet radio through but cell phone towers and land lines remain down are not unimaginable or unprecedented.
(edit it's possible we're confusing each other's meaning. "amatuer radio operator" typically implies "licensed amatuer radio operator", in the same sense of licensed amatuer pilots. It's possible (even very common) to be licensed but not a professional.)
For example, if you read the original article, I certainly wouldn't call the people doing all of that work "amateurs" in any sense other than the laws that apply.
Edit: I'm sorry, I can't leave this one alone. Amateurs do not "clutter" the bands. They have specific frequencies they can use that do not interfere with military or other use. And as a first responder, I can tell you that a lot of "professional" radio usage is very unprofessional to the point of causing problems and even endangering lives. There are many cases where an experienced "amateur" can make much more efficient use of bandwidth than many professionals.
Fortunately, amateur licenses are easy to get and you can do most of what you would be able to do on a modest budget with an amatuer license (with some exceptions) :-)