When a train switches the forward direction, the vehicle-mounted APs in the front and rear change their working status. However, vehicle-mounted devices, such as the switch, cannot detect the change and still forward data to the original working vehicle-mounted AP, causing a data transmission failure. To prevent this situation, you can configure proxied ground devices on a vehicle-mounted AP so that the working vehicle-mounted AP can instruct the vehicle-mounted network devices to update MAC forwarding entries after the train switches the forward direction. In this way, data traffic from the vehicle-mounted network can be forwarded to the working vehicle-mounted AP.