Transmission detection method, device and system

The invention discloses a transmission detection method, device and system, and belongs to the technical field of networks. The method comprises the following steps: a first outlet device receives a first stream through a first inlet interface, acquires detection information of the first stream at the first inlet interface, and determines that a processing mode of a first detection message of the first stream is a BUM processing mode according to forwarding information of the first outlet device. Since the first exit device obtains the detection information of the first stream at the first incoming interface, the first exit device executes the detection of the first stream before copying the BUM message of the first stream, the detection result is prevented from being influenced by copying the BUM message, the detection of the first stream including the BUM message can be realized, the application scene is wide, and the flexibility is relatively high. 一种传输检测方法、装置及系统，属于网络技术领域。该方法包括：第一出口设备通过第一入接口接收第一流，并获取第一流在该第