Virtual LANs
Virtual LAN (VLAN) is a concept in which we can divide the devices logically on layer 2 (data link layer)
Typically, layer 3 (Network Layer) divide the network based on Broadcast Domains i.e. when broadcasting, only the devices in a same broadcast domain (subnet) will receive the packets
Broadcasting is limited to switches as Routers don't forward broadcast packets.
A single switch can have multiple VLANs
A modified ethernet frame, called IEEE 802.1Q Frame Format is used to send the information regarding VLANs along with regular data.
IEEE_802.1Q
Supports virtual local area networking (VLANs) on an IEEE 802.3 Ethernet network
802.1Q adds a 32-bit field between the source MAC address and the EtherType fields of the original frame
