I don't think I understand its purpose. It's a shared wireless communication network for text messages only? So, like, sms-only that is completely independent of the main grid?
Pretty much, yes. It does have some tiny file share capability IIRC (donβt trust me on this) but itβs pretty much just an off grid text based communication platform you connect to with your phone and Bluetooth. Can be extremely long range depending on terrain (line of sight is important)
The routing is simple. Every node repeats everything it hears. A message goes out with a counter - defaults at 3, maximum 7. Every time it's repeated the counter is decremented. At 0 it won't be repeated any more.
You can DM nodes you've seen. You can create your own encrypted channels with a pre-shared key. You can link meshes over the internet through MQTT if you have an internet connected node on each mesh.
Yeah, but not only. For example, I can build a private wifi network, and have my friends join their phones to it. Some bloke across the yard can open his own network, but the two networks will not communicate with each other. The two networks are off-grid, but are independent of each other.
This meshtastic thing sounds awesome! Crowd sourced off-grid network.