Which protocol is widely recognized for establishing VLANs in Ethernet frames?

The protocol recognized for establishing VLANs in Ethernet frames is IEEE 802.1Q. This standard defines the method for tagging Ethernet frames with a VLAN identifier, allowing multiple virtual local area networks (VLANs) to coexist on the same physical network infrastructure. When an Ethernet frame is tagged with 802.1Q, it includes a special identifier within the frame header that indicates which VLAN the frame belongs to. This enables network devices like switches to handle traffic appropriately, ensuring that packets are separated by VLANs regardless of their physical separation.

IEEE 802.1X, while important for port-based network access control, does not define VLAN tagging. Similarly, IEEE 802.1R and IEEE 802.1K focus on other aspects of network management and do not address VLANs directly. Therefore, IEEE 802.1Q is the definitive standard for creating and managing VLANs in Ethernet networks.