By Elaine J. Hom, Associate Editor and Rivka Little, Site Editor

For years, virtual LANs have played an important role in basic enterprise networking, enabling engineers to segment portions of their networks for security, management and scalability. The emergence of virtualization and cloud computing networks only makes understanding VLAN implementation more important. VLANs are key to providing management in a world of virtualization, even where virtual machines are constantly migrating, challenging the very basics of network management. In this guide, learn about old and new uses of VLANs in everything from wireless LANs to data center networks.

Table of contents: VLAN guide
• What is a VLAN?
• What's the best way to configure a VLAN?
• Configuring VLANs for server virtualization
• VLAN and the wireless LAN (WLAN)
• Troubleshooting VLANs

What is a VLAN?

Before implementing or managing a VLAN, one must understand what a VLAN is. A VLAN, or virtual (logical) LAN, is a local area network with definitions that map workstations based on anything except geographic location. For example, a VLAN might have a definition that maps workstations by department, type of user, and so on. The benefits of VLANs include easier management of workstations, load balancing, bandwidth allocation and tighter security.

VLANs become even more efficient when coupled with server virtualization. In a virtualized data center environment, the VLAN strings the physical servers together and creates a route. By allowing virtual machines to move across physical servers in the same VLAN, administrators can keep tabs on the virtual machines and manage them more efficiently.