1. Understanding KaZaA Jian Liang Rakesh Kumar Keith Ross Polytechnic University Brooklyn, N.Y.

2. KaZaA/FastTrack Operation Top file sharing system –3 million active nodes –four clients: KaZaA, KaZaA-lite, Grokster and iMesh Good availability and scalability Proprietary protocol; signaling traffic encrypted –in contrast with Gnutella and e-mule

3. Purpose of Measurement Study Try to understand highly successful file- sharing system –Overlay topology and dynamics –Peer selection –Index management Utilize the KaZaA as a test-bed for further research. –Content pollution research (another paper)

4. Existing Tools and Projects FastTrack encryption algorithm –available from a Web site: http://gift- fasttrack.berlios.de/ KaZaA Media Desktop (KMD) software architecture –http://kazaasearch.narod.ru/

5. Big Picture of Overlay Two layer hierarchy –Ordinary Node (ON) –Super Node (SN)

6. Measurement Apparatus KaZaA Sniffing Platform KaZaA Probing Tool

7. KaZaA Sniffing Platform Poly (Ethernet) Home (cable modem)

8. KaZaA Probing Tool Campus & home based probing –Node list –Workload

9. Signaling Protocol ON-SN session initialSN-SN session initial

10. TCP Connections Evolution Poly campus 4 – 6 hour measurement Cable modem 7-11 hour measurement

11. SN Workload 7 - 11 hours TCP connections evolution 7 - 11 hours workload values evolution

12. Signaling Sessions Lifetime

13. Peer Selection: Node List IP Prefix Match

14. Peer Selection: Workload & RTT

15. Index Management: Sharing Content

16. Port Dynamic and NAT 19,637 unique SN addresses collected Found only 707 SNs (3.6%) use the default 1214 port number. 18,887 SNs (96.3%) use non-default port numbers. Of total unique 64834 peers (SN + ON), 21269 peers (ON) use private IP.

17. Summary of Results 20,000 ~ 40,000 active super nodes Each SN connects to approx. 0.1% of other SNs Highly dynamic connections: over 35% SN- SN durations are less than 30 sec.

18. Summary of results Peer selection uses IP prefix match, workload, RTT and freshness No index exchange between SNs but query forwarding Skewed content distribution: 20% peers provide 70% metadata for sharing.

19. Design Principles for Unstructured P2P Overlays Distributed design –No infrastructure –Avoiding legal attacks. Exploit heterogeneity –Hierarchy –Self organization Load balancing - workload balancing. Explicit locality awareness Shuffle connections in core overlay

20. Design Principles for Unstructured P2P Overlays Properly designed gossip mechanisms –peers have a fresh list of SNs Firewall circumvention –dynamic port numbers –improves availability NAT circumvention