What this means

The IEEE assigned the MA-L block 906FA9 to NANJING PUTIAN TELECOMMUNICATIONS TECHNOLOGY CO.,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 90:6F:A9, it is NANJING PUTIAN TELECOMMUNICATIONS TECHNOLOGY CO.,LTD. hardware.