Though this chapter was long, it helped lay the foundation of your CCNA networking knowledge. The importance of understanding every topic in this chapter cannot be stressed enough. I would strongly suggest going through the chapter again to reinforce the basics.

The chapter started off with the importance of networks, basic network devices and network types and collision and broadcast domains.

Then the seven-layered OSI model was discussed. It is important to remember the functions of all the layers and how they map to the TCP/IP model. Remember that hubs work at Physical Layer, switches at Data-Link Layer and routers at the Network Layer of the OSI model.

The chapter then covered a long discussion on the TCP/IP model and its many protocols. Remember that TCP/IP and Ethernet form a major part of the CCNA exam and have a few chapters dedicated to them.

Lastly, the chapter covered the Cisco three-layer hierarchical model and how it is designed to help implement and manage a complex network.

The next chapter looks at IP addressing. Before heading to it, we suggest you review the CCNA Exam Alerts scattered through this chapter to recap the various important concepts.