Module 04: Networks and Internet Infrastructure

Many people imagine that their data exists somewhere in “the cloud.” The cloud is a useful concept, but the reality is much more physical. Behind most Internet services are buildings filled with computers, networking equipment, storage systems, power infrastructure, and cooling systems.

Many people imagine the Internet as something wireless, virtual, or floating in the cloud. In reality, the Internet depends on a vast physical infrastructure made of cables, data centers, routers, exchanges, and communication equipment spread across the globe. The Internet may feel invisible, but much of it exists in the physical world.

When you open a website, stream a video, send a message, or join a video call, your data travels across networks owned and operated by many different organizations. The Internet is not owned by one company, one government, or one organization. Instead, it is a massive collection of interconnected networks that cooperate to move data around the world.

An IP address is a numerical address used to identify a device on a network. IP stands for Internet Protocol. Internet Protocol is one of the core communication standards that makes the Internet possible.

Module 4 explains how Internet traffic moves through the physical and organizational infrastructure of the global network. It begins with IP addresses and routing, showing that once DNS identifies a destination, devices still need a way to reach it. The module explains IPv4 and IPv6, public and private IP addresses, routers, routing tables, and the routing process that allows packets to move across many connected networks.