@eskimo Thank you for your reply. Can I understand it this way? Bonjour called a system process and obtained the devices discovered by the process through Bluetooth, assuming there are 4 devices ABCD; Then, based on certain device attributes or other information obtained from Bluetooth, devices that do not have Bonjour service capabilities will be filtered out, assuming that AB 2 devices are left behind; In the above process, only Bluetooth was used to quickly discover nearby devices that support Bonjour service. If we don't use Bluetooth, we can also discover devices A and B, and the results are consistent, but may be slower in time?