This first part of the book introduces the most important topics in TCP/IP networking. Chapter 1 introduces the terms, concepts, and protocols for TCP/IP. Chapters 2 and 3 look at how networking devices send data to each other over a physical link, with Chapter 2 focusing on links between nearby devices (local-area networks) and Chapter 3 focusing on links between far-away devices (wide-area networks).
Chapter 4 focuses on the rules of IP routing, which pulls the LAN and WAN links together by forwarding data all the way from one user device to another. Finally, Chapter 5 looks at several other topics, mostly related to how applications make use of the TCP/IP network.