We are both interested in analyzing and to characterize aggregate Internet traffic and the traffic generated by specific applications (games, http, peer-to-peer,..).Our measurement approach is multi-level (sessions, connections, flows, packets, ..) but with a major focus on packet-level analysis. With a packet-level analysis we mean an approach in terms of packet size and inter-packet time. Such modeling approach is simple and at the same time offers the lowest/deepest point of view of network traffic. Network devices (Routers, Switches, Access Points) often operate on a packet-by-packet basis (i.e. buffer management), and network problems (Loss, Delay, Jitter) happen at packet level. Other advantages of studying traffic by observing IPT and PS are the avoidance of any assumption regarding the application-layer protocol characteristics, and the possibility to study, in the same manner, different kind of sources and even mixes of them.