MA-M: a /28 block, one IEEE assigns within a larger OUI when a full /24 isn't needed, covering 1,048,576 addresses.
Prefix20:B3:7F:00:00:00 /28
Vendor addressVia Enzo Lazzaretti, 2/1 REGGIO EMILIA Reggio Emilia IT 42122
Country🇮🇹 Italy
RegisteredMar 16, 2026
Block range20:B3:7F:00:00:00– 20:B3:7F:0F:FF:FF
Address capacity1,048,576
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 →
Ownership timeline
- Mar 16, 2026 – Mar 26, 2026 Chelsio Communications Inc name changedaddress changedcountry changed
- Mar 26, 2026 – present B810 SPA
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.
B810 SPA holds 1 registered blocks in the IEEE registry, ranking #6,242 of 33,421 organizations by block count.