What is the 7th bit of a MAC address commonly referred to as?

The 7th bit of a MAC address is commonly referred to as the Universal/Local (U/L) bit. This bit plays a crucial role in determining the nature of the MAC address. When the U/L bit is set to 0, it indicates that the address is a universally administered address, which means that it has been assigned by a manufacturer. Conversely, if the U/L bit is set to 1, it signifies that the address is a locally administered address, meaning it has been assigned by a network administrator rather than a manufacturer.

Understanding this bit is essential for network designers and engineers, as it guides how devices communicate on the network based on their assigned MAC addresses. The distinction between universally administered and locally administered addresses helps in organizing and managing the network more efficiently, ensuring there are no conflicts between devices.