1. Routing Indices For Peer-to-Peer Systems Arturo Crespo, Hector Garcia-Molina Stanford ICDCS 2002

2. Motivation and ideas Search (text) documents with specific keyword (category) in P2P network  content-based Users only interested in TOP 20 results Each peer stores statistics of Documents shared by itself Documents shared by its neighbors Route query to a “good” peer Sequential search vs parallel search

3. Proposed Methods Compound RI - naive Hop-count RI - improved Exponential RI - best

4. What is routing indices? For A, there are 100 documents available from B (and its descendents) 20 belong to Database category 10 belong to Theory category 30 belong to Languages category “Goodness” of a neighbor

5. Computing goodness For documents of “databases” and “languages”

6. Updating of routing indices New connection RI propagation D+A+J D+A+I

7. Proposed Methods Compound RI – naive Hop-count RI – improved Exponential RI - best

8. Problems and improvements Improved cost model take into account of query messages generated Less update cost RI propagates through limited hops (horizon) Robust against cycles 300 items 250 items

9. Hop-count RI For W, it can reach 30 documents from Y 1 hop away  Y has 30 documents 50 documents from Y 2 hops away  Y1,Y2 have 50 documents

10. Goodness measure in Hop-count RI Goodness of

11. Proposed Methods Compound RI – naive Hop-count RI – improved Exponential RI - best

12. Improvements Hop-count RI exhibits High storage cost High update cost of RI Compress RI of different Hops together Similar to Compound RI with RI update method differs

13. RI Update I changed to  70, 30, 10, 20, 50

14. RI Update D update I’s row as 70, 30, 10, 20, 50 70 30 10 20 50

15. RI Update D sent J’s update as 590, 86.67, 130, 70, 121.67 70 30 10 20 50

16. RI Update 70 30 10 20 50 590 86.67 130 70 121.67 D send A and update as 140, 75, 3.3, 75, 100

17. Experiment

18. Query Message generated Why CRI, HRI, ERI perform much better in the uniform distribution?

19. Effect of index compression

20. Effect of cycles

21. Query message in different network topology

22. Update cost in different network topology

23. END