Chapter 1: Computer Networks and the Internet

Kurose and Keith W. Ross introduces the Internet as the largest engineered system ever created, connecting hundreds of millions of computers, countless communication links, and billions of devices including laptops, smartphones, IoT systems, and more. The chapter lays out a comprehensive overview of computer networking, beginning with what the Internet is, its services, and its protocols. It explains the client-server and peer-to-peer paradigms, and the concept of network edge, core, and access networks. Students are introduced to packet switching and circuit switching, along with the structure of the Internet’s core and the role of Internet Service Providers (ISPs). The authors cover performance metrics such as throughput, delay, and packet loss, and describe the layered architecture of network protocols with the Internet protocol stack (application, transport, network, link, and physical layers). Key application-layer protocols such as HTTP, SMTP, and DNS are briefly outlined. The chapter also discusses security considerations, types of network attacks, and the principles of network architecture, including scalability, reliability, and manageability. By blending real-world examples with foundational principles, the chapter equips readers with the context needed to understand how today’s Internet functions and prepares them to explore the deeper technical details covered in later chapters.