Some results from a GPRS/GSM traffic measurement are presented. First we define session arrivals, durations and volumes in such a way that they can be compared, for example, with measured values of dial-up sessions. Then we study the map of cumulative volume of a single session against elapsed time from the first observed packet of the session. With these maps we study the question of how the major data transfer is typically situated inside a single session’s active duration. For this purpose we introduce three simple statistics which can be used for a rough shape classification.