To understand how your laptop at home talks to Google’s servers in a galaxy far far away, you first need to understand how your laptop at home (or in a data center) talks to another computer located in the same physical location. To do that, all the computers must be connected in some way so that they can transfer signals to each other.

The computer networking stack consists of 7 layers, each of the articles in the series is going to talk about one of these layers. The 7 layers are known as the OSI (Open Systems Interconnection) model. We will start from the “highest” layer which is known as the Application Layer.