What does a VLAN primarily do?

A VLAN, or Virtual Local Area Network, primarily serves the function of breaking up broadcast domains in a layer 2 switch internetwork. A broadcast domain is a logical division of a network where any broadcast sent by a device is received by all other devices within that domain. By creating VLANs, a network can be segmented into multiple broadcast domains without the need for additional physical hardware. This means that devices on different VLANs will not receive broadcasts from each other, which reduces unnecessary traffic and enhances overall network performance.

By isolating traffic not only improves bandwidth utilization but also enhances security since devices on one VLAN cannot directly communicate with devices on another VLAN without proper routing. This is particularly beneficial in large organizations where different departments may need to be kept separate from one another for both operational efficiency and security reasons.

In summary, the primary role of VLANs is to create distinct broadcast domains within a switch, effectively managing traffic patterns and improving the efficiency of the network.