Preface	7
	Contents	13
	1 Introduction	20
	1.1 Introduction to Distributed Systems	21
	1.2 Some Terminology	22
	1.3 Centralized and Decentralized Systems	24
	1.3.1 Resource Discovery	25
	1.3.2 Resource Availability	26
	1.3.3 Resource Communication	28
	1.4 Examples of Distributed Applications	29
	1.4.1 A Web Server: Centralized	29
	1.4.2 SETI@Home: Centralized	31
	1.4.3 Napster: Brokered	32
	1.4.4 Gnutella: Decentralized	32
	1.5 Examples of Middleware	34
	1.5.1 J2EE and JMS: Centralized	34
	1.5.2 Jini: Brokered	35
	1.5.3 Web Services: Brokered	36
	1.5.4 Jxta: Decentralized	36
	1.6 Conclusion	37
	Part I Distributed Environments	39
	2 Peer-2-Peer Systems	42
	2.1 What is Peer to Peer?	42
	2.1.1 Historical Peer to Peer	43
	2.1.2 Binding of Peers	43
	2.1.3 Modern De.nition of Peer to Peer	44
	2.1.4 Social Impacts of P2P	46
	2.1.5 True Peer to Peer?	48
	2.1.6 Why Peer-to-Peer?	49
	2.2 The P2P Environment	50
	2.2.1 Hubs, Switches, Bridges, Access Points and Routers	50
	2.2.2 NAT Systems	51
	2.2.3 Firewalls	53
	2.2.4 P2P Overlay Networks	54
	2.3 P2P Example Applications	56
	2.3.1 MP3 File Sharing with Napster	56
	2.3.2 Distributed Computing Using SETI@Home	57
	2.3.3 Instant Messaging with ICQ	58
	2.3.4 File Sharing with Gnutella	59
	2.3.5 Conclusion	60
	3 Web Services	62
	3.1 Introduction	62
	3.1.1 Looking Forward: What Do We Need?	63
	3.1.2 Representing Data and Semantics	66
	3.2 Web Services	67
	3.2.1 A Minimal Web Service	68
	3.2.2 Web Services Architecture	69
	3.2.3 Web Services Development	71
	3.3 Service-Oriented Architecture	72
	3.3.1 A Web Service SOA	72
	3.4 Common Web Service Misconceptions	74
	3.4.1 Web Services and Distributed Objects	74
	3.4.2 Web Services and Web Servers	74
	3.5 Conclusion	75
	4 Grid Computing	76
	4.1 The Grid Dream	76
	4.2 Social Perspective	77
	4.3 History of the Grid	78
	4.3.1 The First Generation	79
	4.3.2 The Second Generation	80
	4.3.3 The Third Generation	81
	4.4 The Grid Computing Architecture	82
	4.4.1 Virtual Organizations and the Sharing of Resources	83
	4.5 To Be or Not to Be a Grid: These Are the Criteria...	86
	4.5.1 Centralized Control	86
	4.5.2 Standard, Open, General-Purpose Protocols	87
	4.5.3 Quality Of Service	88
	4.6 Types of Grid	88
	4.7 The Globus Toolkit 2.x	89
	4.7.1 Globus Tools	90
	4.7.2 Security	91
	4.7.3 Information Services	92
	4.7.4 Data Management	93
	4.7.5 Resource Management	95
	4.8 Comments and Conclusion	96
	Part II Middleware, Applications and Supporting Technologies	99
	5 Jini	102
	5.1 Jini	103
	5.1.1 Setting the Scene	103
	5.2 Jini’s Transport Backbone: RMI and Serialization	103
	5.2.1 RMI	104
	5.2.2 Serialization	105
	5.3 Jini Architecture	108
	5.3.1 Jini in Operation	110
	5.4 Registering and Using Jini Services	112
	5.4.1 Discovery: Finding Lookup Services	112
	5.4.2 Join: Registering a Service (Jini Service)	113
	5.4.3 Lookup: Finding and Using Services (Jini Client)	115
	5.5 Jini: Tying Things Together	116
	5.6 Organization of Jini Services	118
	5.6.1 Events	118
	5.7 Conclusion	119
	6 Gnutella	120
	6.1 History of Gnutella	120
	6.2 What Is Gnutella?	121
	6.3 A Gnutella Scenario: Connecting and Operating Within a Gnutella Network	124
	6.3.1 Discovering Peers	124
	6.3.2 Gnutella in Operation	124
	6.3.3 Searching Within Gnutella	125
	6.4 Gnutella 0.4 Protocol Description	126
	6.4.1 Gnutella Descriptors	127
	6.4.2 Gnutella Descriptor Header	128
	6.4.3 Gnutella Payload: Ping	129
	6.4.4 Gnutella Payload: Pong	129
	6.4.5 Gnutella Payload: Query	130
	6.4.6 Gnutella Payload: QueryHit	130
	6.4.7 Gnutella Payload: Push	131
	6.5 File Downloads	132
	6.6 Gnutella Implementations	134
	6.7 More Information	134
	6.8 Conclusion	134
	7 Scalability	136
	7.1 Social Networks	136
	7.2 P2P Networks	138
	7.2.1 Performance in P2P Networks	138
	7.3 Peer Topologies	140
	7.3.1 Centralized	141
	7.3.2 Ring	141
	7.3.3 Hierarchical	141
	7.3.4 Decentralized	143
	7.4 Hybrid Topologies	143
	7.4.1 Centralized/Ring	143
	7.4.2 Centralized/Centralized	144
	7.4.3 Centralized/Decentralized	144
	7.5 The Convergence of Napster and Gnutella	146
	7.6 A Southern Side-Step	147
	7.7 Gnutella Analysis	148
	7.7.1 Gnutella Free Riding	148
	7.7.2 Equal Peers?	149
	7.7.3 Power-Law Networks	149
	7.8 Further Reading	150
	7.9 Conclusion	150
	8 Security	152
	8.1 Introduction	152
	8.2 Design Issues	154
	8.2.1 Focus of Data Control	154
	8.2.2 Layering of Security Mechanisms	155
	8.2.3 Simplicity	157
	8.3 Cryptography	157
	8.3.1 Basics of Cryptography	157
	8.3.2 Types of Encryption	159
	8.3.3 Symmetric Cryptosystem	159
	8.3.4 Asymmetric Cryptosystem	160
	8.3.5 Hash Functions	161
	8.4 Signing Messages with a Digital Signature	162
	8.5 Secure Channels	163
	8.5.1 Secure Channels Using Symmetric Keys	164
	8.5.2 Secure Channels Using Public/Private Keys	164
	8.6 Secure Mobile Code: Creating a Sandbox	166
	8.7 Conclusion	167
	9 Freenet	170
	9.1 Introduction	170
	9.2 Freenet Routing	171
	9.2.1 Populating the Freenet Network	171
	9.2.2 Self-Organizing Adaptive Behaviour in Freenet	172
	9.2.3 Requesting Files	173
	9.2.4 Similarities with Other Peer Organization Techniques	174
	9.3 Freenet Keys	175
	9.3.1 Keyword-Signed Keys	176
	9.3.2 Signed Subspace Keys	177
	9.3.3 Content Hash Keys	178
	9.3.4 Clustering Keys	179
	9.4 Joining the Network	180
	9.5 Conclusion	181
	10 Jxta	182
	10.1 Background: Why Was Project Jxta Started?	182
	10.1.1 Interoperability	183
	10.1.2 Platform independence	183
	10.1.3 Ubiquity	184
	10.2 Jxta Overview	185
	10.2.1 The Jxta Architecture	185
	10.2.2 Jxta Peers	186
	10.2.3 Identi.ers	187
	10.2.4 Advertisements	188
	10.2.5 Messages	188
	10.2.6 Modules	189
	10.3 Jxta Network Overlay	189
	10.3.1 Peer Groups	189
	10.3.2 Rendezvous Nodes	190
	10.3.3 Pipes	191
	10.3.4 Relay Nodes	193
	10.4 The Jxta Protocols	193
	10.4.1 The Peer Discovery Protocol	193
	10.4.2 The Peer Resolver Protocol	194
	10.4.3 The Peer Information Protocol	195
	10.4.4 The Pipe Binding Protocol	195
	10.4.5 The Endpoint Routing Protocol	195
	10.4.6 The Rendezvous Protocol	195
	10.5 A Jxta Scenario: Fitting Things Together	195
	10.6 Jxta Environment Considerations	196
	10.6.1 Security	196
	10.6.2 NAT and Firewalls	197
	10.7 Comment	197
	10.8 Conclusion	197
	Part III Middleware Deployment	200
	11 Distributed Object Deployment Using Jini	204
	11.1 RMI Security	204
	11.2 An RMI Application	205
	11.2.1 The Java Proxy	205
	11.2.2 The Server	206
	11.2.3 The Client	208
	11.2.4 Setting up the Environment	209
	11.3 A Jini Application	210
	11.3.1 The Remote Interface	211
	11.3.2 The Server	211
	11.3.3 The Client	213
	11.4 Running Jini Applications	215
	11.4.1 HTTP Server	215
	11.4.2 RMID Daemon	215
	11.4.3 The Jini Lookup Service	216
	11.4.4 Running the Service	216
	11.5 Conclusion	217
	12 P2P Deployment Using Jxta	218
	12.1 Jxta Programming: Three Examples Illustrated	218
	12.1.1 Starting the Jxta Platform	219
	12.1.2 Discovery	220
	12.1.3 Creating Pipes	223
	12.2 Running Jxta Applications	227
	12.3 P2P Environment: The Jxta Approach	228
	12.3.1 Peer Con.guration Using Jxta	228
	12.3.2 Peer Con.guration Management Within Jxta	230
	12.3.3 Running The Examples	233
	12.3.4 Jxta and P2P Advert Availability	233
	12.3.5 Expiration of Adverts	234
	12.4 Conclusion	235
	13 Web Services Deployment	236
	13.1 SOAP	236
	13.1.1 Just Like Sending a Letter. . .	237
	13.1.2 Web Services Architecture with SOAP	238
	13.1.3 The Anatomy of a SOAP Message	240
	13.2 WSDL	241
	13.2.1 Service Description	242
	13.2.2 Implementation Details	243
	13.2.3 Anatomy of a WSDL Document	244
	13.3 UDDI	247
	13.4 Using Web Services	248
	13.4.1 Axis Installation	248
	13.4.2 A Simple Web Service	250
	13.4.3 Deploying a Web Service Using Axis	251
	13.4.4 Web Service Invocation	252
	13.4.5 Cleaning Up and Un-Deploying	254
	13.5 Conclusion	254
	Part IV From Web Services to Future Grids	256
	14 OGSA	260
	14.1 OGSA	261
	14.1.1 Grid Services	261
	14.1.2 Virtual Services	263
	14.1.3 OGSA Architecture	264
	14.2 OGSI	265
	14.2.1 Globus Toolkit, Version 3	268
	14.3 WSRF	268
	14.3.1 Problems with OGSI	269
	14.3.2 Grid Services or Resources?	270
	14.3.3 OGSI Functionality in WSRF	270
	14.3.4 Globus Toolkit, Version 4	271
	14.4 Conclusion	271
	A Want to Find Out More?	272
	A.1 Grid Computing	272
	A.2 P2P Computing	273
	A.3 Distributed Object Computing	274
	A.4 Web Services	275
	B RSA Algorithm	278
	References	280
	Index	288
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