Based on a distributed cloud that includes a central node and one or more edge nodes, a determination is made that a first device is incapable of normal operation, the first device being in a first edge node. A first communication link model of the first edge node is acquired. The first communication link model includes a detection module in the central node, one or more second devices in the first edge node, and one or more third devices configured to transmit data between the detection module and the one or more second devices. The first communication link model indicates a communication link relationship among the detection module and devices in the first communication link model. Respective operation states of the devices are detected. Link fault information is determined, the link fault information including information of a faulty device in the first communication link model.