What is VLAN in a computer network?

A virtual local area network (virtual LAN) is the logical grouping of network nodes.

In other words, a virtual LAN is any broadcast domain that is partitioned and isolated in a network. A VLAN allows several networks to work virtually as one LAN.

It gives an advantage to connect multiple devices whether it is wired or wireless to a combined single network. It works as a broadcast domain.

Benefits of VLAN

The benefits that are provided by implementing VLANs are as follows −

  • Reduce the number of routers.

  • All devices can be controlled by the same level.

  • It offers a broadcast domain that reduces the traffic.

  • It gives more security in the network.

Advantages of using VLAN

These are some of advantages of using VLAN which are as follows −

  • Reduce congestion on a large LAN.

  • Waste of administration

  • Confinement of broadcast domains

Uses of VLAN

The uses of VLANs are given below −

  • It is used in miniature business companies in order to facilitate the enhanced execution via imposing extra security, spreading and transferring the network devices, reducing the delay and minimizing the traffic burden over the network.

  • It is used in university campuses and academic blocks for implementation of instrument segregation, accessibility monitoring, restricting the circulation region with respect to network traffic, host versatility for Wi-Fi consumers and network supervision in a decentralized manner.

Working of VLAN

When a switch receives an Ethernet frame, the frame will either already have a VLAN tag or switch will insert a VLAN tag into the Ethernet header.

If the frame was received from another switch, that switch will have inserted the VLAN tag, whereas frames coming from network devices, such as computers will not have a VLAN tag.

If you are using switch defaults for VLANs, the VLAN tag that will be placed on the frame is VLAN1.

When placing a VLAN tag on the Ethernet frame, four bytes of data, which make up the VLAN tag, are inserted before the Type field.

This 4-byte header includes several pieces of information.