What this means
The IEEE assigned the MA-L block 5C3977 to Juniper 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 5C:39:77, it is Juniper Networks hardware.
Frequently Asked Questions
Who owns MAC prefix 5C3977?
5C3977 is registered to Juniper 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. Juniper Networks's block covers 16,777,216 addresses.
What devices use 5C3977?
Any network device with a MAC address starting 5C:39:77 was manufactured by or for Juniper Networks.