What this means
The IEEE assigned the MA-L block ECD9D1 to Shenzhen TG-NET Botone 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 EC:D9:D1, it is Shenzhen TG-NET Botone Technology Co.,Ltd. hardware.