Theuser-drivendynamicsofpeerparticipation,orchurn,areaninherentpropertyofPeer-to-Peer(P2P)systemsthatshouldbetakenintoaccountinboththedesignandevaluationofanyP2Papplication.Whilepriorstudieshaveshownthatpeerparticipationishighlydynamic,theyhavenotprovideddetailedmodels,neededforsimu