1. Taming the Torrent: A Practical Approach to Reducing Cross-ISP Traffic in Peer-to-Peer Systems David R. Choffnes and Fabián E. Bustamante Speaker: Wally Chang Publisher: SIGCOMM 2008

2. Motivation P2P traffic is massive and random Transmission usually performs better in the same ISP Billing problems between ISPs

3. Previous Works ISPs guide peers for partnership formation ◦ Biased peer selection by Bindal et al. (ICDCS 2006), Aggarwal et al. (CCR 2007) and Xie et al. (SIGCOMM 2008) Remaining issues ◦ Peer adoption ◦ Legal problem

4. Proposed Method Hypothesis ◦ If two peers are close to the same CDN replica, they are close to each other ◦ Links between “nearby” hosts cross few ISPs Measuring the relative network distance by comparing name of the CDN replica

5. CDN Service The web site with CDN service will store its components in CDN replica When a end user visit a web page… ◦ Request components from the web site ◦ The CDN DNS will tell where to get the components The CDN replica and the end user are “nearby” (SIGCOMM 06)

6. Comparing the Similarity of CDN replica Records the percentage of each CDN replica Cosine similarity Server name Percentage of connecting to this server

7. Data Collection Ono ◦ An extension to the BitTorrent Type of data ◦ RTT (ping) ◦ IP hop (traceroute) ◦ AS hop (traceroute & AS query tool) Figures are plotted based on a 2-week study in December, 2007

8. Reducing Cross-ISP Traffic

9. Finding Nearby Peers

10. Ono in Different ISPs (1/3)

11. Ono in Different ISPs (2/3)

12. Ono in Different ISPs (3/3)

13. Using Different CDN Customers Different CDN customers may have different quality of service in CDN

14. Effect of Different CDN Customers (1/2) The more CDN replica names, the better

15. Effect of Different CDN Customers (2/2) “AB” is using Limelight CDN service, which is a smaller CDN service company

16. Discussion Overhead ◦ Requires periodically DNS lookup  18KB up and 36KB down per day Free-riding on CDN service providers Practical ◦ No extra infrastructure needed ◦ Performance improvement

17. Reference Ao-Jan Su et al, “Drafting Behind Akamai (Travelocity-Based Detouring)”, In Proc. of ACM SIGCOMM 2006., September 2006 Ao-Jan Su et al, ”Relative Network Positioning via CDN Redirections”, In Proc. of the International Conference on Distributed Computing Systems (ICDCS), (to appear) June 2008 David R. Choffnes and Fabián E. Bustamante,” Taming the Torrent: A practical approach to reducing cross-ISP traffic in P2P systems”, In Proc. of ACM SIGCOMM 2008., August 2008.