VLAN stands for Virtual Local Area Network. A VLAN is a network that collects a set of network ports on a switching device into a single broadcast domain. VLANs are most often used over Ethernet networks. This allows the administrator to use the physical LAN infrastructure to organize any set of network components and resources together into a single logical network. An administrator can designate specific ports on switches that can connect to this logical network. This technology was ratified as the IEEE 802.1Q standard and is supported by most advanced switch manufacturers including Cisco, HP, 3Com, Extreme Networks and Foundary.
Virtual Local Area Networks were created to solve certain problems in switched environments.
- VLANs can be used to split up oversized broadcast domains
- VLANs can be used to increase network security
- VLANs allow greater flexibility in the placement of hosts
VLANs are not much different from standard networks. To get data on one VLAN to another VLAN, you must have a device that supports routing. Some "switches" possess routing capabilities.