What is a VLAN, and how does it work?

A VLAN, or Virtual Local Area Network, is a network of devices that appear to be on the same network despite their geographical distribution.

A VLAN is a subcategory of LAN (Local Area Network) that is designed to communicate over a larger geographical area. It is a group of devices on one or more LANs that are configured to communicate as if they were attached to the same wire, when in fact they are located on a number of different LAN segments. This is achieved by using a VLAN ID, which is assigned to each device in the VLAN.

VLANs work by applying tags to network frames and handling these tags in networking systems – creating the appearance of a network that is not limited by location. These tags are managed by network hardware, typically switches and routers. When a device sends a frame to another device in the same VLAN, the frame is sent just as if they were on a traditional LAN. If a device sends a frame to a device in a different VLAN, the networking hardware must route the frame, just as if the devices were on different LANs.

VLANs are used to achieve scalability, security and ease of network management and can quickly adapt to change in network requirements and relocation of workstations and server nodes. They are often used in business settings, where a company might have networks in different locations that need to appear as one network to the users.

The use of VLANs can also improve network performance by reducing the need to send broadcasts and multicasts on all devices. Instead, these types of traffic can be confined to the VLAN where they are needed. This can significantly reduce unnecessary traffic on the network, improving overall performance.

In summary, a VLAN is a flexible and scalable way to manage your network, allowing devices to communicate as if they were on the same network, regardless of their physical location. It provides increased security and improved network performance, making it a popular choice for businesses and organisations with large networks.