So when XSIS (Xerox System Integration Standards?) first started selling MAC address blocks in the early 1980s, I think it cost $1k for 16M mac addresses (168 a

So when XSIS (Xerox System Integration Standards?) first started selling MAC address blocks in the early 1980s, I think it cost $1k for 16M mac addresses (168 addresses per penny). So there are only 16M blocks of mac addreses available, and it IS possible to run out, if vendors waste the addresses. I don't know what registration costs from The IEEE right now, but once the equivalent of $16B is spent on mac addresses, we will run out of blocks. Maybe today they are selling smaller blocks but the MAC is basically divided into 16M blocks (specified by the first 24 bits / 3 bytes) - each with a registered owner or "unassigned") and 16M MACs within the block (the lower 24 bits). That's why you can enter a MAC address into a lookup website and find out who made the NIC (google search "mac address lookup"): https://aruljohn.com/mac.pl https://aruljohn.com/mac.pl