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Routing Indices For Peer-to-Peer Systems. Arturo Crespo, Hector Garcia-Molina Stanford ICDCS 2002. 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
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Routing Indices For Peer-to-Peer Systems Arturo Crespo, Hector Garcia-Molina StanfordICDCS 2002
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
Proposed Methods • Compound RI - naive • Hop-count RI - improved • Exponential RI - best
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
Computing goodness • For documents of “databases” and “languages”
D+A+J D+A+I Updating of routing indices New connection RI propagation
Proposed Methods • Compound RI – naive • Hop-count RI – improved • Exponential RI - best
Problems and improvements 250 items 300 items • Improved cost model • take into account of query messages generated • Less update cost • RI propagates through limited hops (horizon) • Robust against cycles
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
Goodness measure in Hop-count RI • Goodness of
Proposed Methods • Compound RI – naive • Hop-count RI – improved • Exponential RI - best
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
RI Update I changed to 70, 30, 10, 20, 50
RI Update 70 30 10 20 50 D update I’s row as 70, 30, 10, 20, 50
RI Update 70 30 10 20 50 D sent J’s update as 590, 86.67, 130, 70, 121.67
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
Query Message generated Why CRI, HRI, ERI perform much better in the uniform distribution?