Network service device, linking management device and operation methods thereof

A network service device includes a storage device, a communication device and a processing device. The storage device stores a message conforming to ultra-reliable low-latency communication (URLLC). The processing device is coupled to the storage device and the communication device. The processing device receives a linking message of a linking management device through the communication, and establishes a linkage according to linking message. The processing device transmits the message conforming to URLLC to the linking management device through the communication device.