A LAN is a local area network that delivers the nodes that are connected to it with direct access to each other. Usually it consists of more than one Ethernet switch and computers on various LANs communicate with each other via the Layer 3 (IP), using a router.
A virtual LAN is composed of a subset of the ports within one switch or subsections of different ports situated on more than one switch. Systems situated on one VLAN cannot see the traffic linked with other systems by default. This is for all systems that are on the same network using other VLANS. The benefit of using a VLAN is that it enables network administrators to divide their networks so that they match the security and functional necessities of their systems. This is done without needing to run newer cables or create significant changes within the present network infrastructure. IEEE 802.1Q is the normal defining VLANs; and the tag or identifier of a VLAN is composed of 12 bits within the Ethernet frame. This creates an innate limit of 4096 VLANs within a single LAN. Systems can be separated into logical groups because the ports on switches can be linked to more than one VLAN.