802.1Q is the networking standard that allows the application of tags to Ethernet frames. These tags act as labels that designate frames to specific broadcast domains, allowing devices within the same physical network to be partitioned into distinct logical networks. Understanding this is crucial for network segmentation and efficient traffic management. In contrast, IEEE 802.3af pertains to Power over Ethernet, which provides electrical power along with data on Ethernet cabling. The 802.11ac standard relates to wireless networking and does not involve frame tagging for Ethernet networks. LACP is used for port aggregation, combining several physical ports to enhance redundancy and throughput, rather than labeling frames for network segmentation.