universally administrated address (UAA)

In the MAC address there is a marking whether it is managed universally or locally. For this marking there is the U/L bit, which is the seventh bit in the first byte of the MAC address. U/L stands for Universal/Local. If the U/L bit is set to 0 it is a Universally Administrated Addresses (UAA), which is managed by the IEEE. If the U/L bit is set to 1 it is a Locally Administered Address( LAA).

The UAA address comprises the first 24 bits of the 48-bit MAC address.