Switches can open up new ways of organizing not only your computer network, but your business itself.

network (LAN) switches also make it easier to add new users and applications. Thus it's important to have a tool that can be used to manage network traffic even more efficiently.

That's where a virtual local-area network (VLAN) comes in. By using VLANs, a capability available on Ethernet LAN switches, companies can bring networked-based resources to the user, rather than the user to the resources.

How VLANs work

A VLAN allows the network administrator to set up a logical rather than physical LAN that connects a related group of users regardless of where those users are physically located on the network.

A variety of strategies can be used to group users into VLANs. For example, the users might be grouped according to their department or functional team. In general, the goal is to group users so that most of their traffic stays within the VLAN.

What VLANs provide

When you configure VLANs, the network can take advantage of the following benefits:

• Broadcast control: VLANs can contain broadcast and multicast traffic so that it doesn't affect other parts of the LAN.

• Security: No users outside of that VLAN can communicate with the users in the VLAN and vice versa unless the information crosses a switch-based or standalone router. This strict level of security can be highly desirable for certain projects and applications.

• Performance: You can assign users who require high-performance networking to their own VLANs. You might, for example, assign an engineer who is testing a multicast application and the servers the engineer uses to a single VLAN. The engineer experiences improved network performance by being on a "dedicated LAN," and the rest of the engineering group experiences improved network performance as well.

• Network management: Software on the switch allows you to assign users to VLANs and, later, reassign them to another VLAN. With a VLAN, there is no re-cabling required — simple network management tools allow you to logically reconfigure the LAN in seconds.