It’s a new network stack that overlays & runs independently of the legacy stack. Ipv4/6/i2p/tor/ble/nfc/serial/pipe interface compatibility, excessively forgiving to low bandwidth & local traffic (whose prioritization seems to scale well), and the system touts universal addressing & routing - with strong cryptographic assurances for identification, proving delivery & private message transport.
I think it works, it may even work well. I ran out of excuses to try it out, I’ll end up giving it a go soon.
https://r8io.github.io/rns-presentations/source/001-introduction.html#/_reticulum_network_stack