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How does the internet work? This subject you'll learn the basics of how data goes from one computer to another. We use the OSI -- or Open Systems Interconnection -- model to describe the internet.

Layer 7 is the application layer, such as your web browser communicating over HTTP. Layer 6 is presentation layer, such as secure transmission of your data over HTTP. Layer 5 is the session layer, such as Sockets. In Layer 4, we have the transport layer, which includes TCP and UDP. On Layer 3 we have the network layer, which includes routers to get data from one point to another. Then on layer 2 we have data links, which transfers data between two directly connected nodes. Finally on layer 1 is the physical layer -- the actual hardware of the internet.

Knowing these layers will help you be better at web development, have a deeper understanding of how to protect yourself on the internet, and understand the challenges facing the development of web infrastructure.