I don't remember the name of the software/protocol, but I once saw a demonstration of something that seemed similar to the Internet using amateur radios communicating with each other. I think they had either email or something functionally similar, but I was told that it didn't use Ethernet or IP at all (if I'm remembering correctly).

Edit: found it, it was TARPN https://tarpn.net/t/packet_radio_networking.html