Architecture and Methods for Flexible Content Management in Peer-to-Peer Systems

von: Udo Bartlang

Vieweg+Teubner (GWV), 2010

ISBN: 9783834896452 , 240 Seiten

Format: PDF, OL

Kopierschutz: Wasserzeichen

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Architecture and Methods for Flexible Content Management in Peer-to-Peer Systems


 

Foreword

6

Danksagung

8

Abstract

9

Zusammenfassung

11

Contents

13

List of Figures

17

List of Tables

19

1 Introduction

20

1.1 Sample Scenarios of a Peer–to–Peer-Based Content Repository

22

1.1.1 Cross-Enterprise Business Collaboration

22

1.1.2 Intra-Enterprise Knowledge Management

25

1.2 Problem Statement and Research Challenges

29

1.2.1 Research Challenges Regarding the Content Model

30

1.2.2 Research Challenges Regarding the Content Repository Model

30

1.2.3 Research Challenges Regarding the Peer–to–Peer Model

32

1.3 Main Research Contributions of this Thesis

33

1.4 Publications

35

1.5 Outline

36

2 Background

38

2.1 Content Repositories

39

2.1.1 Content versus Data

41

2.1.2 Content Management

42

2.1.3 Content Management Systems

42

2.2 Distributed Systems, Algorithms, and Methods

44

2.2.1 Node Model

45

2.2.2 Communication Models

45

2.2.3 Failure Models

47

2.2.4 Consensus Algorithms

48

2.2.5 Fault-Tolerant State Machines

50

2.2.6 Group Communication

51

2.2.7 Dynamic Code Loading

51

2.3 Peer–to–Peer Systems

52

2.3.1 Centralised Peer–to–Peer Overlays

53

2.3.2 Unstructured Peer–to–Peer Overlays

54

2.3.3 Structured Peer–to–Peer Overlays

55

2.4 Distributed File Systems

56

2.4.1 Client–Server-Based Systems

57

2.4.2 Peer–to–Peer-Based Systems

59

2.5 Distributed Database Systems

61

2.5.1 Client–Server-Based Systems

62

2.5.2 Peer–to–Peer-Based Systems

64

2.6 Summary

65

3 Analysis of Content Repository Requirements in a Peer–to–Peer Case

67

3.1 Methodology of Analysis

67

3.2 Definition of Functional Building Blocks Using the Content Repository API for Java Technology

68

3.2.1 Content Repository Model

69

3.2.2 Content Repository Functions

71

3.2.3 Operational Scope

79

3.3 Dependence Relationships between Functional Building Blocks

80

3.3.1 Service Functionality Dependence

80

3.3.2 Influence Dependence

82

3.4 Suitability of Peer–to–Peer Overlays for Content Repository Functionality

83

3.4.1 Functional Content Repository Requirements for a Peer–to–Peer Approach

84

3.4.2 Non-Functional Content Repository Requirements for a Peer–to–Peer Approach

84

3.5 Summary

86

4 Design of a Generic Peer–to–Peer Content Repository System Architecture

88

4.1 Architectural Model

89

4.1.1 Logical View

89

4.1.2 Process View

89

4.1.3 Development View

90

4.1.4 Physical View

90

4.1.5 Scenarios

90

4.2 Generic Content Repository Architecture

91

4.2.1 Modular Decomposition

91

4.2.2 Persistent Storage Management

94

4.3 Generic Content Mapping

97

4.3.1 Item Naming Concept

97

4.3.2 Flexible Content Item Policies

100

4.4 Generic Peer Architecture

101

4.4.1 Internal Peer Structure

101

4.4.2 Dynamic Service Integration

104

4.5 Related Work

106

4.6 Summary

108

5 Methods for Flexible Content Repository Functions in Structured Peer–to–Peer Overlays

109

5.1 DhtFlex: A Distributed Algorithm for Flexible Atomic Data Management

109

5.2 System Context of DhtFlex

111

5.2.1 System Model

111

5.2.2 System Architecture

112

5.2.3 System Interface

116

5.3 Functionality of DhtFlex

116

5.3.1 Annotated Data Resources

117

5.3.2 Recast Case

117

5.3.3 Put Case

123

5.3.4 Get Case

125

5.3.5 Overlay Breakup Detection

127

5.4 Flexible Content Repository Functions

128

5.4.1 Content Mapping

128

5.4.2 Persistent Content Storage

130

5.5 Related Work

133

5.6 Summary

135

6 Methods for Flexible Content Repository Functions in Hybrid Peer–to–Peer Overlays

136

6.1 Reconfigurable Peer–to–Peer Service Groups

137

6.2 System Context of Peer–to–Peer Service Groups

139

6.2.1 System Model

139

6.2.2 System Architecture

140

6.2.3 System Interface

144

6.3 Functions of Peer–to–Peer Service Groups

145

6.3.1 Lifecycle Management

145

6.3.2 Decentralised Dynamic Code Loading of Service Functions

149

6.3.3 Consensus-Based Peer–to–Peer Group Communication

154

6.4 Flexible Content Repository Functions

163

6.4.1 Content Mapping

163

6.4.2 Persistent Content Storage

165

6.5 Related Work

168

6.6 Summary

171

7 Evaluation

173

7.1 Methodology

173

7.1.1 Architecture Evaluation

173

7.1.2 Method Evaluation

175

7.2 Peer–to–Peer Content Repository System Architecture

176

7.2.1 Architectural Styles

176

7.2.2 Quality Attributes

177

7.2.3 Scenarios

179

7.3 Methods for Flexible Content Repository Functions in Structured Peer–to–Peer Overlays

181

7.3.1 Reliability

181

7.3.2 Consistency

183

7.3.3 Reconfigurability

192

7.3.4 Scalability

192

7.3.5 Performance

196

7.4 Methods for Flexible Content Repository Functions in Hybrid Peer–to–Peer Overlays

201

7.4.1 Reliability

201

7.4.2 Consistency

202

7.4.3 Reconfigurability

203

7.4.4 Scalability

203

7.4.5 Performance

204

7.5 Summary

208

8 Conclusion and Outlook

210

8.1 Conclusion

210

8.2 Future Work

213

Bibliography

217