Why You Need More Than One LAN

Why You Need More Than One LAN

A VLAN is simply a LAN that is created by configuring a switch, so that a subset of its ports is considered to be in the same broadcast domain. But why would you bother? Couldn't you just leave the switch alone and let it work like always, with one physical LAN? Sure. In fact, often times, particularly in small networks, you do not need to use VLANs. However, in medium to large enterprise networks, VLANs are quite popular. As my daughter would say (over and over again, by the way), "Why?" Well, I'll give you a few of the typical reasons over the next few pages of this chapter. This is not an exhaustive list, but it highlights a few of the popular reasons.