In a data packet transmission network, a stream of packets of data sent by a first terminal passes in transit through at least one network equipment with which there is associated a stream measurement unit, wherein the first terminal and the measurement unit are connected to a collection unit. The measurement method comprises the following steps the first terminal generates a packet stream according to a predetermined rule destined for the second terminal the measurement unit analyzes at least one packet of the stream passing through the network equipment the first terminal dispatches to the collection unit a description of a stream of sent packets, comprising a list including at least sizes of the sent packets the stream measurement unit dispatches to the collection unit a stream description, comprising at least a sum of the sizes of the analyzed packets; and the collection unit identifies each analyzed packet of the stream as a function of the stream description and of the predetermined rule so as to correlate, packet by packet, the stream description and the description of stream of sent packets.