Yapısal olmayan eşler arası bilgisayar ağlarında katkısız katılımı engelleme

The peer-to-peer (P2P) network paradigm has attracted a significant amount ofinterest as a popular and successful alternative to traditional client-server modelfor resource sharing and content distribution. However, researchers have observedthe existence of high degrees of free riding in P2P networks which poses a seriousthreat to effectiveness and efficient operation of these networks, and hence totheir future. Therefore, eliminating or reducing the impact of free riding on P2Pnetworks has become an important issue to investigate and a considerable amountof research has been conducted on it.In this thesis, we propose two novel solutions to reduce the adverse effects of freeriding on P2P networks and to motivate peers to contribute to P2P networks.These solutions are also intended to lead to performance gains for contributingpeers and to penalize free riders. As the first solution, we propose a distributedand localized scheme, called Detect and Punish Method (DPM), which dependson detection and punishment of free riders. Our second solution to the free ridingproblem is a connection-time protocol, called P2P Connection Management Protocol(PCMP), which is based on controlling and managing link establishmentsamong peers according to their contributions.To evaluate the proposed solutions and compare them with other alternatives,we developed a new P2P network simulator and conducted extensive simulationexperiments. Our simulation results show that employing our solutions in a P2Pnetwork considerably reduces the adverse effects of free riding and improves theoverall performance of the network. Furthermore, we observed that P2P networksutilizing the proposed solutions become more robust and scalable.