The measurement of quality of service (QoS) for peer-to-peer (P2P) networks is principally stimulated by the increasing need to model, and regulate the nondeterministic behaviour of this network kind that has recently achieved great success, and popularity: representing a high part of the total Internet data-communications. The stochastic nature, and the complexity of P2P networks make difficultly measurable the QoS. This paper presents the stochastic analysis platform for peer-to-peer networks (SAPP2P), which is enable to measure the QoS of every P2P network (described by means of an opportune language) by the simulation of its dynamics (until 10/sup 7/ peers, and with calculus time of [10/sup 3/ - 10/sup 4/]s). This measurement technique becomes an useful aid in design, and optimization of highly performing P2P networks.