Part 3. Network architectures

After covering the details of various protocols at all layers of the TCP/IP model and how to configure them in Cisco IOS, let’s zoom out and look at the bigger picture. In part 3 of this volume, we will examine various network architectures and how the technologies we have previously covered fit together to form a coherent whole.

Chapter 15 starts with local area network (LAN) architectures, ranging from simple small office/home office (SOHO) networks used by individuals and small businesses to two- and three-tier campus LANs employed by medium and large enterprises and data center networks designed to support the high-performance servers that run modern applications. Chapter 16 then zooms out even further, looking at how LANs can be connected together to form wide area networks (WANs) that can span the globe; in this chapter, we will address the “widest” network of all: the internet. We will also cover two main kinds of virtual private networks (VPNs)—secure connections established over the public internet.

Finally, chapter 17 addresses two key components of most enterprises’ IT infrastructure: virtualization technologies, such as virtual machines (VMs) and containers, and cloud computing—better known as “the cloud.” Enterprises of all sizes take advantage of cloud computing for its flexibility, scalability, and convenience, and this chapter lays a solid foundation for your understanding of cloud computing’s key concepts. The goal of part 3 as a whole is to give you a holistic view of modern network architectures while addressing the specific points that Cisco expects you to know for the CCNA exam.