What this means
The IEEE assigned the MA-L block 84B8B8 to Motorola (Wuhan) Mobility Technologies Communication 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 84:B8:B8, it is Motorola (Wuhan) Mobility Technologies Communication Co., Ltd. hardware.