MA-L: a full /24 OUI block, IEEE's largest, covering 16,777,216 addresses.
Prefix00:21:0F:00:00:00 /24
Vendor address1943 Isaac Newton Sq Reston VA US 20190
Country🇺🇸 United States
RegisteredApr 14, 2008
Block range00:21:0F:00:00:00– 00:21:0F:FF:FF:FF
Address capacity16,777,216
AdministrationUniversally administered: its prefix comes from a block registered through the IEEE Registration Authority
TransmissionUnicast: addressed to a single device
SourceIEEE Registration Authority
Address capacity is the size of this registered block, not a count of devices actually manufactured or online. Registration identifies the organization holding the block, not a specific device model or unit.
Curious how a prefix like this turns into a full address? See how MAC addresses are structured →
Example addresses in this block
Where this block sits
The nearest registered blocks of the same size on either side of this one in IEEE's address space.
Cernium Corp holds 1 registered blocks in the IEEE registry, ranking #8,097 of 33,427 organizations by block count.