The IEEE established the 802.1Q standard in 2018 in an effort to reduce network congestion by breaking large networks into smaller ones that won't grab up too much available bandwidth. The standard also increases secure communication between segments of internal networks.
In practice, the 802.1Q standard inserts a VLAN tag into a frame header, which includes the preamble, destination MAC address, source MAC address, Ether type/size, payload, and CRC/FCS. (CRC/FCS stands for "cyclic redundancy check" and "frame check sequence," which both use algorithms to check the transmission integrity of internet frames.) Among all the items included in a frame, the 802.1Q standard inserts an additional item called an "802.1Q header, which identifies a member/device belonging to a VLAN.