Networking

Networking, like onions, comes in layers. Unlike onions, networks have about 5 layers

layer 1: Physical. The lowest layer, the physical connection. This could be something like wifi, ethernet, radio connection. Learn physics.

layer 2: Link. Next to lowest, this layer contains information about the physical layer, and allows you to send bytes over it.

layer 3: Network. This layer assigns addresses to different communicating things on the network. Most people are familiar with IPv4 and IPv6, but there are less popular alternatives.

layer 4: Transport. This is what the T in TCP stands for. TCP basically guarantees that all your bytes have been transferred, and that they look like a single stream.

layer 5: Application. This is a two byte internal identifier that your computer uses to know which application made which request. (PORT number).