No internet required… In this video, I build a public Reticulum node and test whether it can bridge completely different networks into one encrypted communication path. I send messages from a normal phone over LTE, through the internet and Starlink, then off-grid over LoRa—eventually using a $20 drone-mounted relay to reach a phone with no internet connection at all.
Except the LTE, Internet and Starlink would be your ISP. It’s whatever facilitates an IP(v6) address to connect to the web.
That is what he used, but it is possible to go from Reticulum to Reticulum device without the need for those services, he just happened to use them in the video example. In this hypothetical future, those services won’t be completely cut out anytime soon, but it is possible to rely on them much lesser.