Originally Posted by pittsburgpam
It's networking. Chapter 2 is about DoD (Department of Defense) and OSI modeling, what protocols are used at each of 11 layers, what each does and how it works, what ports are used for what process, the classes of IP addresses, what ranges for each class, etc. etc. etc. All in one chapter.
Go ahead and skip to the next chapters. It will make more sense once you see how & why it's used and some of it you will never see again--particularly references to the OSI model--LOL!
Seriously! Sounds like you are studying for your Network + exam or possibly just the first step--the A+. Skip ahead--there will be very few if any questions about the "good old days" of networking on the exam. I'm from the good old days and there were very few of those type questions back then.