VLAN or Virtual Lan is the name of the protocol standard from IEEE to 802.1q, which specifies the ethernet requisites to implement an independent area of a LAN isolated from another LAN with a tag on ethernet protocol(Layer 2).
A Virtual LAN, commonly known as VLAN is a logically independent network. Several VLANs can co-exist on the same switch (switch) in order to divide a local area network (physical) network in more than one (virtual), creating separate broadcast domains. A VLAN also makes it possible to put in the same broadcast domain, hosts with different physical locations and connected to different switches. Another purpose of a virtual network is to restrict access to network resources without considering the network topology, but this method is questionable.
Virtual LANs operate at Layer 2 of the OSI model. However, a VLAN is usually configured to map directly to a network or IP subnet, which gives the impression that the layer 3 is involved.