This chapter covers the following topics:

Welcome to the amazing world of computer networking as you prepare for your Cisco CCNA Routing & Switching 200-120 exam. This chapter will help you get your feet wet by explaining what a network is, the different types of networks, and different devices used in them.

Once you know the basics of networking, this chapter will help you understand both the OSI reference model and the TCP/IP model. Both of these models are very important for you to understand from not only from the CCNA exam perspective, but also for the rest of your networking career. Most of this chapter is dedicated to these two reference models.

This chapter also covers Network Applications, Ethernet Technologies and ends with a discussion on the Cisco Three Layer Model which was created by Cisco to help design, implement, and troubleshoot networks.