A VLAN, or Virtual LAN, is a logical overlay network that groups together a subset of devices that share a physical LAN, isolating the traffic for each group. VLANs operate at Layer 2 of the network, the Ethernet level, and partition a single switched network into a set of overlaid virtual networks that can meet different functional and security requirements. VLANs offer several advantages such as simplified administration, increased performance, greater flexibility, and cost savings.
Here are some key points about VLANs:
- A VLAN is a collection of devices or network nodes that communicate with one another as if they made up a single LAN, when in reality they exist in one or several LAN segments.
- VLANs partition a single switched network into a set of overlaid virtual networks that can meet different functional and security requirements.
- VLANs can improve performance for devices on them by reducing the amount of traffic a given endpoint sees and processes.
- VLANs break up broadcast domains, reducing the number of other hosts from which any given device sees broadcasts.
- VLANs can be configured and assigned based on port, protocol, or subnet criteria, making it possible to alter VLANs and change network design when necessary.
- VLANs allow network administrators to automatically limit access to a specified group of users by dividing workstations into different isolated LAN segments.
Overall, VLANs are used to segment a network into smaller, more manageable parts, which can improve performance, security, and flexibility.
