Black-box analysis of Internet P2P applications

Abstract

After P2P file-sharing and VoIP telephony applications, VoD and live-streaming P2P applications have finally gained a large Internet audience as well. In this work, we define a framework for the comparison of these applications, based on the measurement and analysis of the traffic they generate. In order for the framework to be descriptive for all P2P applications, we first define a minimum set of observables of interest: such features either pertain to different layers of the protocol stack (from network up to the application), or convey cross-layer information (such as the degree of awareness, at overlay layer, of properties characterizing the underlying physical network). The framework is compact (as it allows to represent all the above information at once), general (as is can be extended to consider features different from the one reported in this work), and flexible in both space and time (as it allows different levels of spatial aggregation, and also to represent the temporal evolution of the quantities of interest). Using the minimum feature set, we analyze some of the most popular P2P application nowadays, highlighting their main similarities and differences. We then apply the framework, using also different features and metrics, to two interesting case study: namely, the detection of malfunctioning or misbehaving peers, and a fine-grained analysis of P2P network-awareness and friendliness.