Network programming prelude

"A program is like a poem: you cannot write a poem without writing it."

– E. W. Dijkstra

Building a medium through which machines can communicate with each other over the internet is a complicated task. There are different kinds of devices that communicate over the internet, running different OS and different versions of applications, and they need a set of agreed upon rules to exchange messages with one another. These rules of communication are called network protocols and the messages devices send to each other are referred to as network packets.

 

For the separation of concerns of various aspects, such as reliability, discoverability, and encapsulation, these protocols are divided into layers with higher-layer protocols stacked over the lower-layers. Each network packet is composed of information from all of these layers. These days, modern operating systems already ship with a network protocol stack implementation. In this implementation, each layer provides support...