A Virtual Local Area Network (VLAN) is a group of hosts that feature a like set of requirements and can communicate as though they were all connected via the same wires. However, unlike a traditional LAN, a VLAN is not necessarily all in the same place, and the hosts involved in the network can be located practically anywhere. All VLANs have the exact same attributes as a traditional physical local area network, though they can be configured via software instead of having to actually relocate the hosts.
Many VLANs are designed as replacements to the services that are traditionally provided by routers on physical LANs. VLANs are able to tackle issues like network management, security, and scalability with ease.
VLANs are known as Layer 2, or Data Link layer, constructs which transfer data between network nodes. Because they are Layer 2 constructs, they can interface with Layer 3 IP subnets with a one to one relationship.
How are VLANs designed?
The IEEE assigned IEEE 802.1Q as the protocol by which to configure virtual LANs. IEEE 802.1Q provides for a header with a 2-byte protocol identifier and another 2-byte tag control information. These are known...