Webopedia Staff
Last Updated May 24, 2021 7:51 am
Short for Organizational Unique Identifier, the first 24 bits of a MAC address for a network-connected device, which indicate the specific vendor for that device. The IEEE assigns OUIs to vendors. (The last 24 bits of the MAC address are the device s unique serial number, assigned to the device by the manufacturer.)

The OUI sometimes is referred to as the Vendor ID.