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What is VLAN Tagging?

IEEE 802.1Q, or VLAN Tagging, is a networking standard written by the IEEE 802.1 workgroup. It allows multiple-bridged networks to transparently share the same physical network link without leakage of information between networks. IEEE 802.1Q — along with its shortened form dot1q — is commonly used to refer to the encapsulation protocol used to implement this mechanism over Ethernet networks.

What is VLAN?

VLAN, otherwise known as Virtual LAN, is a type of local area network innovation that enables administrators to break up physical connectivity from logical network connectivity. In contrast, conventional LAN is much more limited when compared to VLAN because the former is constrained by physical connectivity alone.

Moreover, VLAN is composed of an assembly of gadgets linked on one or more LANs that are arranged so that they could connect to each other as though they were attached to the same wire despite the fact that they are placed on a number of various LAN sections.

IEEE 802.1Q defines the meaning of a VLAN with respect to the specific conceptual model underpinning bridging at the MAC layer and to the IEEE 802.1D spanning tree protocol. This protocol allows for individual VLANs to communicate with one another using a switch with layer-3 capabilities, or simply a router.

VLAN Categories

ATM VLAN: This LAN type utilizes the LAN emulation (LANE) protocol for the sake of Ethernet packet mapping into ATM cells. It also delivers the packets to their ultimate destination via the ATM address conversion of an Ethernet MAC address.

Protocol-based VLAN: IP traffic is filtered by this VLAN category using a specific protocol such as IPX from neighboring end-stations by configuring a switch with a compendium of mapping layer-3 protocol types to VLAN membership ¡§C.

MAC-based VLAN: Individual MAC addresses are mapped into VLAN membership via configuring a switch with an access list that handles the whole procedure.

Port-based VLAN: This VLAN type is responsible for the configuration of each and every physical switch port via an access list that identifies membership in a collection of VLANs.

Since VLANs are based more on logical than physical connections, they're considered to be very versatile when it comes to resource optimization, bandwidth allocation, and host/user management. However, quite a lot of small office or home-based networks will probably not find this method necessary in going about network management because of its virtual nature.

Then again, businesses that use an internal office network, a public network (such as a WiFi hotspot), or a networked point-of-sale system (like those found in major shopping outlets) will benefit the most out of this extensive and widespread network variant just as long as the individual LANs are kept separated for security reasons yet still located on a general physical network for easier supervision.