What this means
The IEEE assigned the MA-L block 20B399 to Enterasys. 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 20:B3:99, it is Enterasys hardware.
Frequently Asked Questions
Who owns MAC prefix 20B399?
20B399 is registered to Enterasys 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. Enterasys's block covers 16,777,216 addresses.
What devices use 20B399?
Any network device with a MAC address starting 20:B3:99 was manufactured by or for Enterasys.