Here's the thing:
You have a Rpi(Short for Raspberry) in your room. Your friend Jack lives in another city. You two work on projects and need to share files. Your friend bought a Rpi for something but its useless now. You plan to connect two of these Rpis so that you can send or receive files(Security aside). How do you connect them?
I know not much about networking but If you do you can answer it. Just summery or blog post link would be fine.
I dont know much about RP, but you might also need to set up the public private keys for your ssh connection prior to getting started.
coz its needed for initial connection of 2 normal devices on secure shell.