What this means
The IEEE assigned the MA-L block A4B121 to Arantia 2010 S.L.. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting A4:B1:21, it is Arantia 2010 S.L. hardware.
Frequently Asked Questions
Who owns MAC prefix A4B121?
A4B121 is registered to Arantia 2010 S.L. in the IEEE MA-L registry.
What does the MA-L registry type mean?
An MA-L assignment, the IEEE's original OUI format, gives the vendor the first three octets and 16,777,216 device addresses under them. Arantia 2010 S.L.'s block covers 16,777,216 addresses.
What devices use A4B121?
Any network device with a MAC address starting A4:B1:21 was manufactured by or for Arantia 2010 S.L..