Understanding KaZaA

Both in terms of number of participating users and in traffic volume, KaZaA is one of the most important applications in the Internet today. Nevertheless, because KaZaA is proprietary and uses encryption, little is understood about KaZaA’s protocol, architecture and signaling traffic. We have built a measurement platform for collecting and measuring KaZaA’s signaling traffic. These measurements provide insight on KaZaA’s architecture, protocol, and overlay behavior. The reader should take away from this paper a deep understanding of one of the largest distributed systems ever to be deployed in the Internet.