Chapter7.Adding Local (Network) Roadways for No Extra Money

Chapter 7. Adding Local (Network) Roadways for No Extra Money

What You Will Learn

After reading this chapter, you should be able to

• Define the terms LAN, VLAN, and broadcast domain

• Compare and contrast the concept of a physical LAN and a virtual LAN

• Explain how a single switch operates when multiple VLANs are present

• List several reasons for wanting to use VLANs

• Explain the need for VLAN trunking, and list the two options for trunking on Ethernet

At this point in your reading, you already have a pretty detailed view of how LANs work. You can buy some network interface cards (NICs) and install them in some computers, cable each NIC to a switch, and you've created a LAN. As long as the PCs have some networking software on themand most operating systems today include TCP/IPyou're all set to use the network.

As it turns out, there are many reasons why you would want more than one LAN. Regardless of the reason, you can create another LAN by buying more NICs, more cables, and more switches. However, there's a better way to create more LANs by using virtual LANs (VLANs).

In this chapter, you will read about physical LANs, with particular attention to some concepts that will help you understand VLANs. Then, you'll read about VLANs and how they are created. Along the way, you'll learn some of the reasons why you might want to use VLANs.