A VLAN is a virtual LAN. Technically, a VLAN is a broadcast domain generated by switches.
How a Switch Distinguishes between VLANs
This is done by associating the work stations to a specific VLAN using a specified format. This is known as VLAN membership. There are four prominent VLAN membership methods
- Port (Layer 1 of the OSI model )
- MAC address (Layer 2 of the OSI model )
- Protocol type – EtherType (Layer 2 header contains the protocol type field)
- Subnet address (Note that even though the Switch accesses Layer 3 information,
it still works at Layer 2 of OSI model only.)