Virtual Lan (Vlan)

An Ethernet virtual local area network (VLAN) is a logical LAN that is implemented on top of a physical LAN. VLANs allow you to segment your network into separate broadcast domains, which can improve network performance and security. In most cases, each VLAN is assigned its own IP subnet, which allows devices on different VLANs to communicate with each other through a router. However, it is also possible to configure a VLAN so that all devices in the VLAN share the same IP address range.

This is known as an overlapping VLAN. Overlapping VLANs can be used to create multiple levels of security within a single physical LAN. For example, you could configure one VLAN for general Internet access and another VLAN for sensitive financial data. Any device that needs to access the financial data would need to be connected to both VLANs. VLANs are typically configured using special purpose hardware known as a switch. Switches that support VLANs are sometimes referred to as “trunk” switches.