1. Canon in G Major: Designing DHTs with Hierarchical Structure Prasanna Ganesan(Stanford University) Krishna Gummadi(University of Washington) Hector Garcia-Molina(Stanford Universiy)

2. Motivating Scenario P-2-P Application –File sharing –Multi-media sharing –Collaborative computation –General purpose lookup directories

3. Motivating Scenario Where is the paper “Canon in G Major”?

4. Hierarchy Design Single Point Over Head Isolating faults Adapting growth

5. Flat Design(DHT) No single point of failure

6. Flat & Hierarchical Design Flat Design –No single point of failure –P2P(DHT) Hierarchical Design –Isolating faults –Adapting growth –DNS

7. Canonical System

8. Crescendo Chord Merged Chord

9. Chord Circular N-bit ID space Node x links to succ(x+2^i)

10. Crescendo Merge –Merging multiple rings –Multi-level hierarchies Incremental –New node joins bottom up Links per node –Log(n)

11. Merging

12. Merging Rule –Closer than any other black node –Y=succ(x+2^i)

13. Routing Crescendo (intra-domain) Greedy Clockwise routing Path Locality -Fault isolation -Security -Efficiency 0 -> 12

14. Routing Crescendo (inter-domain) Path convergence :closest node to destination in the domain :same destination node same last node in the domain 0 -> 13 -Distributed Caching -Bandwidth savings 5 -> 13

15. Other DHTs Chord => Crescendo CAN => Can-Can Symphony => Cacophony Kademlia => Kandy

16. Evaluation Links/node Hops/query latency

17. Number of Links vs. Number of Levels

18. Levels vs. Routing Hops

19. Path Locality

20. Critique Strong point –Novel Idea –Good development of idea Weak point –Poor motivating scenario

21. New Idea Do you have any New Idea?