By: Elliott Cepin - Started May 28, 2025 | WIP
I just completed my third year as a computer science major at the University of Arizona. When I joined the university, I made the unfortunate assumption that it was the university's responsibility to teach me everything I'd ever need to know. This did not turn out to be the case. Over the last few years, I've learned very little to do with web development. I hardly know what the internet is. I've interfaced with some HTML, CSS, and PHP through my job, but I've never been formally taught about any of them. By the end of this document, I will have a basic understanding of:
The internet, put simply, is a network of networks[1]. A network, in this context, is a set of connected computers [2]. This definition, however, is insufficient. Consider two separate networks. Both networks, A and B, have two connected computers. If we connect networks A and B, we might be able to say that it is an internet; we had two networks, and then they got connected. We should now have a network of networks. Alternatively, it is just as intuitive to assert that we simply have a larger network. Now that the computers from network A and network B are connected, we have four connected computers. So either, we have two connected networks A and B or one bigger network AB. At the end of the day, both are true. In order to differentiate between networks like A or B and AB, we need new terminology. The networks A and B are called local-area networks (LANs)[3]. In order to understand network AB, we need to know a bit more about how A and B are connected.
As observed previously, the computers in a network are connected. Computers in a local network are connected by a device called a switch. Switches allow one device to forward packets[4] to another[5]. In order for a network to be connected to the internet, the switch must be connected to a router. A router connects devices in one network to other networks[6]. A set of networks connected by routers is called a wide-area network (WAN)[7]. Network AB is part of a wide-area network.