From here on, a different voice takes the lead.
The earlier parts built the mental model: Compute, Store, Network as the three pillars; programs becoming processes; CPUs executing one instruction at a time; memory arranged in a hierarchy of speed.
This part follows one of those pillars all the way to the floor. It is written by Kumar Pratik, co-founder of GeekyAnts and a working engineer who has spent more than a decade building, breaking, and explaining networks. He writes longer than I do. He goes deeper than I do. He will not let you skip the homework.
How to Read These Ten Chapters
Read them slowly. Some are short. Most are not. Every one ends with exercises that are the actual point of the chapter, the writing is just the prompt.
When you finish, you will have followed a single packet from the metal contacts of an RJ45 jack, through glass on the seabed, up through OSI layers, into a kernel ring buffer, across a syscall boundary, and into the application that finally consumed it. You will also know why the most valuable company in the world is currently NVIDIA, and why that has very little to do with GPUs and very much to do with how chips talk to each other.
A Few Rules Before You Begin
Do not trust this book. Validate everything in it. If you find something that is wrong, that is good. Most learning happens during validation, not consumption.
Do not skip the struggle. The chapters end with questions and homework. The homework is not optional. It is the actual book. The chapters are just the prompts.
Do not ask other people for the answer. Ask them better questions. Pratik will explain why.
Turn the page.