Free-riding and whitewashing in peer-to-peer systems

Abstract

-We devise a simple model to study the phenomenon of free-riding and the effect of free identities on user behavior in peer-to-peer systems. At the heart of our model is a strategic user of a certain type, an intrinsic and private parameter that reflects the user's generosity. The user decides whether to contribute or free-ride based on how the current burden of contributing in the system compares to her type. We derive the emerging cooperation level in equilibrium and quantify the effect of providing free-riders with degraded service on the emerging cooperation. We find that this penalty mechanism is beneficial mostly when the "generosity level" of the society (i.e., the average type) is low. To quantify the social cost of free identities, we extend the model to account for dynamic scenarios with turnover (users joining and leaving) and with whitewashers: users who strategically leave the system and re-join with a new identity. We find that the imposition of penalty on all legitimate newcomers incurs a significant social loss only under high turnover rates in conjunction with intermediate societal generosity levels.

When doing nothing is something. How task allocation strategies compromise between flexibility, efficiency, and inactive agents

“…Individual inactivity is also found in many other organized systems (shirking in human organizations : Hamermesh 1990; the elderly as unused capacity in human societies: Brugiavini et al 2005;Li and Tolley 2007;Angelini et al 2009; unused capacity in cloud computing: Fox et al 2009;Varia 2010; free-riding in peer to peer networks: Asvanund et al 2004;Feldman et al 2006) and thus begs further exploration. While inactivity could result from individual selfishness, shift-work, or simplified living conditions in the lab (Schmid-Hempel 1990), there is no clear empirical evidence to support any of these hypotheses (Table 2).…”

Network pricing: can both ISP and P2P benefit?

“…For instance, if P2P traffic were throttled or blocked or if usage-based pricing induced more P2P participants to become free riders, the availability and performance of P2P networks would deteriorate. We have observed past trends in P2P research to change the technical and/or economic incentives of users to deal with the free-riding problem [3,[16][17][18][19][20][21][22][23][24][25][26]. The sustainability of both the ISP business model and P2P applications is in challenge.…”

Incentive mechanisms for trustworthy routing based on game model of the strategies of nodes in P2P networks

“…Take Fig. 1 for example, there are three paths, , i k w represents the integrated trust value of the paths through Node j 2 and Node j 3 estimated by Node i, which can be expressed as 2 , , …”

“…(1) and (2). Assuming N is defined as the number of total nodes in P2P network, a middle-node will execute Eq.…”

“…However, the autonomy of nodes leads to the diversity of the actions of P2P nodes, which induces the routing to be easily disserved by malicious behaviors of the nodes. End-nodes in the routing can take malicious actions [1] such as free-riding [2] , forgery attack [3] , collusion [4] and betrayal [5] , etc. Take P2P file-sharing application as an example, 25% of the files are forged documents or viruses [6] .…”