Abstract:

Free riding in peer-to-peer (P2P) systems means a peer utilizing other peers’ network resources without contribution, which will cause severe degradation of the service quality in P2P streaming systems. A two-class fluid model was introduced to model and analyze the free riding problem. With this model, two scenarios including without seeders and with seeders were considered, and a quantitative analysis of the effect of free riding on the performance of P2P streaming systems particularly in the steady state was put forth. The result showed that both honest peers and free riders could achieve a much lower download time in the scenario with seeders than that without seeders, and thus it was essential to introduce the mechanisms to incentivize the seeders to stay in the system. The free riders could benefit greatly from the streaming server and the seeders, and thus it is important to introduce differentiated service for the server and seeders in P2P streaming systems.

Key words: P2P streaming, free riding, fluid model, incentive mechanism