Scalable Summary Based
Retrieval in P2P Network
Wolfgang Muller ,Martin
Eisenhardt and Andreas Henrich
CIKM’05
Outline
Introduction
Rumorama : The basic idea
A closer look at Rumorama
Experiments
Conclusion
Introduction
Summary-based system
GIOSS
Glossary Of Servers Server
PlanetP
GIOSS in Small P2P Networks
RUMORAMA
Scalable PlanetP
GIOSS
Knows the location of a set S of IR servers
Use summaries to select a subset C of S
drawback
Depends on GlOSServer always on-line
Ability to forward all the requests
PlanetP
Each peer knows the summaries of all
other peers
How peer introduces itself to the network
PlanetP is not scalable
RUMORAMA
Hierarchization of PlanetP-like networks
Leaf net
The small PlanetP network viewed by a peer
Friends
Neighbors
Enable peer to reach other leaf net
RUMORAMA
Structural Invariant & Query
Algorithm
Friend mask
依照peer id 的prefix來決定friends
Query
Query mask : [x]
Friend mask : [f]
Two cases
[x] = [f]
[x] < [f]
RUMORAMA (cont.)
Adapting to Varying Network Size
Nsplit(Pa)
Maximum的friend個數
Two steps
Step 1:append a bit to its mask
Step 2:some friends become neighbors
Nmerge(Pa)
Minimum的friend個數
Mask[x1] Mask[x]
Joining and Leaving the Network
Join Pa
(101011…..)
(111100…..)
Pn Pn
(001111…..) (001111…..)
(000100…..)
(001000…..) (101000…..)
Leave
Peer 可以直接leave
Experiments
Experiments (cont.)
Friend coverage
Query coverage
Experiments (cont.)
Experiments (cont.)
Conclusion
Summaries會影響query的result
Friends彼此之間每隔一段時間會交換
information，若peer所存的summary多，
cost會提高
解決leaving node的問題