Not first, but eventually the layers are needed to solve problems that evolve when your software needs to operate in someone else's network. That said, it's no

Not first, but eventually the layers are needed to solve problems that evolve when your software needs to operate in someone else's network. That said, it's not very hard to directly talk "ethernet" using raw sockets. Here's an example if you're interested: https://gist.github.com/austinmarton/1922600 https://gist.github.com/austinmarton/1922600.