6-16 VLAN ConfigurationWhen configuring VLAN, go to these sections for information you are interested in:z Introduction to VLANz Configuring Basic VLAN Settingsz Configuring Basic Settings of a VLAN Interfacez Port-Based VLAN Configurationz MAC-Based VLAN Configurationz Protocol-Based VLAN Configurationz Displaying and Maintaining VLANz VLAN Configuration ExampleIntroduction to VLANVLAN OverviewEthernet is a network technology based on the Carrier Sense Multiple Access/Collision Detect(CSMA/CD) mechanism. As the medium is shared, collisions and excessive broadcasts cannot beavoided on an Ethernet. To address the issue, virtual LAN (VLAN) was introduced.The idea is to break a LAN down into separate VLANs, that is, Layer 2 broadcast domains wherebyframes are switched between ports assigned to the same VLAN. VLANs are isolated from each otherat Layer 2. A VLAN is a bridging domain, and all broadcast traffic is contained within it, as shown inFigure 6-1.Figure 6-1 A VLAN diagramVLAN 2VLAN 5Switch BSwitch ARouterA VLAN is logically divided on an organizational basis rather than on a physical basis. For example, allworkstations and servers used by a particular workgroup can be connected to the same LAN,regardless of their physical locations.VLAN technology delivers the following benefits:
