Why Kad's routing table has hundreds of peers

Abstract

Kad is the most popular P2P file sharing system. Previous works only focus on the global peers' collection or monitoring the lookup traffic. Based on our online measurement, we find that each benign peer's routing table only has 400–600 peers. We further study the Kad's source codes and track the routing table's change process. And finally, we explain that the unique Kad routing table's structure and the total online peer number lead to this result. We also do the large-scale experiment to prove our conclusion.