What this means
The IEEE assigned the MA-L block A4218A to Nortel Networks. 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 A4:21:8A, it is Nortel Networks hardware.
Frequently Asked Questions
Who owns MAC prefix A4218A?
A4218A is registered to Nortel Networks 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. Nortel Networks's block covers 16,777,216 addresses.
What devices use A4218A?
Any network device with a MAC address starting A4:21:8A was manufactured by or for Nortel Networks.