Understanding the Design Benefits of Virtual LANs

Understanding the Design Benefits
of Virtual LANs
Remember that layer 2 switches break up collision domains and that only routers can break up
broadcast domains. However, virtual LANs can be used to break up broadcast domains in layer 2
switched networks. Routers are still needed in a layer 2 virtual LAN switched internetwork to enable
the different VLANs to communicate with each other.
There are many benefits to creating VLANs in your internetwork. Remember that in a layer 2
switched network, the network is a
flat network
, as shown in Figure 14.1. Every broadcast packet
transmitted is seen by every device on the network, regardless of whether the device needs to
receive the data.