It’s an overlay network, it can fit in place anywhere. Use ipv4/6/tor/i2p/paper/bluetooth/pipe/ham/whatever-else-the-fuck-is-a-medium-of-communication. Idk how well two tin cans & a string would work, but if you can tap out morse code faster than 3 bytes per second, you can maintain a vpn connection lol

https://github-wiki-see.page/m/markqvist/Reticulum/wiki/Awesome-Reticulum