802.1Q

acronym

networking

Stands for: IEEE 802.1Q (VLAN tagging)

The IEEE standard that adds a VLAN tag to an Ethernet frame - the reason one physical link can carry many virtual LANs.

802.1Q inserts a four-byte tag carrying a 12-bit VLAN ID (4,094 usable) and a priority field into the Ethernet header. A tagged link between switches is a trunk; untagged access ports drop a device into a single VLAN. It is the foundation of segmentation on switched networks, and it lives in the 802.1 working group, the architecture arm of the 802 family.

Also known as: 802.1q, dot1q, vlan tag, vlan trunking

Sources

IEEE 802.1 Working Group (official)

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