The behaviour of the routers' buffer is of primary importance when studying network traffic, since it may modify some of this characteristics, as delay or jitter, and may also drop packets affecting the Quality of Service (QoS) of different services. As a consequence, the characterization of this buffer is interesting, especially when real-time flows are being transmitted. This work presents a preliminary study of how to determine the technical and functional characteristics of buffers (as e.g., behaviour, size, limits, input and output rate) of a network path. Two different methodologies are considered on two test scenarios; real measurements permit the estimation of some parameters of the intermediate buffers as size, input and output rates, in a network path including different devices across the Internet.