What this means
The IEEE assigned the MA-L block 3C0AF3 to CLOUD NETWORK TECHNOLOGY SINGAPORE PTE. LTD.. 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 3C:0A:F3, it is CLOUD NETWORK TECHNOLOGY SINGAPORE PTE. LTD. hardware.