  All the routers include a buffer in order to enqueue packets waiting to be
transmitted. The behaviour of the routers' buffer is of primary importance when
studying network traffic, since it may modify some characteristics, as delay or
jitter, and may also drop packets. As a consequence, the characterization of
this buffer is interesting, especially when real-time flows are being
transmitted: if the buffer characteristics are known, then different techniques
can be used so as to adapt the traffic: multiplexing a number of small packets
into a big one, fragmentation, etc. This work presents a preliminary study of
how to determine the technical and functional characteristics of the buffer of
a certain device (as e.g. behaviour, size, limits, input and output rate), or
even in a remote Internet network node. Two different methodologies are
considered, and tested on two real scenarios which have been implemented; real
measurements permit the estimation of the buffer size, and the input and output
rates, when there is physical or remote access to the "System Under Test". In
case of having physical access, the maximum number of packets in the queue can
be determined by counting. In contrast, if the node is remote, its buffer size
has to be estimated. We have obtained accurate results in wired and wireless
networks.
