MA-M: a /28 block, one IEEE assigns within a larger OUI when a full /24 isn't needed, covering 1,048,576 addresses.
Prefix38:B1:4E:50:00:00 /28
Vendor address741 Brookhaven Ave Upton NY US 11973
Country🇺🇸 United States
RegisteredMar 9, 2026
Block range38:B1:4E:50:00:00– 38:B1:4E:5F: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 →
Example addresses in this block
Where this block sits
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38:B1:4E:40:00:00 /28
Noitom Robotics Technology (Beijing) Co.,Ltd.
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38:B1:4E:60:00:00 /28
Universal Robots A/S
The nearest registered blocks of the same size on either side of this one in IEEE's address space.
Brookhaven National Laboratory holds 2 registered blocks in the IEEE registry, ranking #1,666 of 33,427 organizations by block count.
Other blocks registered to Brookhaven National Laboratory