What IEEE standard supports VLAN tagging?

The IEEE standard that supports VLAN tagging is 802.1q. This standard defines the format for VLAN tagging in Ethernet frames, allowing for the identification and separation of different virtual LANs (VLANs) within the same physical network. When a frame is tagged with a VLAN ID, it enables network devices to differentiate between frames belonging to different VLANs, thereby facilitating better network segmentation and management.

The significance of VLAN tagging lies in its ability to enhance network efficiency and security by allowing multiple logical networks to coexist on a single physical network infrastructure. This helps in optimizing bandwidth usage and reducing congestion.

Other standards listed do not deal with VLAN tagging. For instance, 802.1x focuses on port-based network access control for implementing authentication. Meanwhile, 802.1d defines the Spanning Tree Protocol (STP) used to prevent loops in network topologies. Finally, 802.3 pertains to Ethernet networking standards but does not include VLAN tagging specifications.