A method for signaling a piece of congestion information regarding a first data stream routed by a first node in a network. The method includes the following acts implemented by a second node via which the first data stream and at least a second data stream are routed: obtaining a piece of congestion information regarding the second data stream, the congestion information indicating that a third node, via which the first data stream is routed, has detected a congestion situation for a routing of the second stream in a data transfer plane; checking that the first data stream has a priority level lower than that of the second data stream; and sending, to the first node, a control message in a control plane, the control message carrying the congestion information.