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Table of Contents
Chapter 1 Introduction to Data Communications 1 Chapter Objectives 1
Essential Elements of Communication 2 Message 2 Sender 4 Receiver 4
Medium 4
Data Communications Applications 5
Combined Applications 7 Requirements of an Online System 7
Performance 7
Consistency 9
Flexibility 9
Availability 9
Reliability 10
Recovery 10
Security 10
Application 19
Presentation 19
Session 19
Transport 19
Network 20
The Software Environment 20
Data Communications 22 Database Management System 22
Transaction Processing 23 Summary 25
Key Terms 26
Review Questions 27
Chapter 2 Media and Data Transmission 29 Chapter Objectives 29
Transmission Media 30
Transmission Errors 53
Error Prevention 55
Error Detection 56
Parity Check 56
Digital Voice Using Pulse Code Modulation 61
Interfaces 62
Summary 66
The Rationale Behind Networks 72
Large Data Transfers 72
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Chapter 4 LAN Hardware, Topologies, and Media Access Control 89 Chapter Objectives 89
Server Platforms 90
File Services 90
File Servers 90
Database Servers 91
Server Memory 94
Processor Speed 96
Backup Devices 99
Ring Topology 208
Bus Topology 222
Star Topology 222
The ANSI Fiber Distributed Data Interface (FDDI)
Standard 227
Data Link Layer Functions 228
MAC Protocols 222
Topology and Protocol Tradeoffs 222
CSMA/CD Buses 222
Summary 225
Table of Contents ix
Chapter 5 LAN System Software and LAN Considerations 729 Chapter Objectives 229
Generic Functions of LAN System Software 230
CBT—Network Operating System Overview 232
LAN OS Implementations 232
Novell Operating Systems 235
Microsoft's Windows NT 236
Banyan Vines 138
Backup Software 239
Hardware Configuration 240
Application Settings 242
Type of Use 253
Distance and Medium 254
Vendors and Support 257
Key Terms 160
Review Questions 161
Chapter 6 WAN Hardware and Data Link Control 763 Chapter Objectives 163
Wide Area Network Configurations 163
CBT—Enterprise Network Evolution 164
Terminals 166
Multiplexers 170
Hierarchical Network 275
WAN Data Link Protocols 2 78
Asynchronous Transmission 178
Synchronous Transmission 180
CBT—HDLC/SDLC 183
Centralized Routing Determination: The Network Routing Manager 2 #5
Distributed Routing Determination 186
Key Terms 189
Review Questions 290
Chapter 7 WAN System Software and WAN Implementations 797 Chapter Objectives 292 The OSI Session Layer 292
Data Communications Access Methods 293 Transaction Control Process 295
Table of Contents xi
Maintaining Context 297
Memory Management 198
Transaction Routing 199
Transaction Log 200
Internet Naming Conventions 207
Information Superhighway Uses 222
SNA Layers 223
Session Types 224
LU Types 225
Addressing 218
International Networks 220
Chapter 8 Network Interconnections 227 Chapter Objectives 227 Why Multiple Networks? 228
The OSI Reference Model Revisited 229
Repeaters 230
Bridges 233
Routers 239
TCP/IP 241
ISO Routing Standards 244
X.25 Networks 246 X.25 Networks and the OSI Layers 247
Current X.25 Network Implementations 247
Connection Options 248
X.25 Network Equipment 250
CBT—X.25/Frame Relay 251
LAN-to-Host Connections 252
Asynchronous Connections 254
Summary 259
Network Management Objectives 264
Supporting System Users 264
Cost-Effectiveness 268
LAN Versus WAN and Enterprise Network Management 270
LAN Management Tasks 273
WAN Management Tasks 280
A Generic Network Management System 284
Network Management Protocols 288
Netview 289
Netview/PC 289
Netview/6000 290
Key Terms 292 Review Questions 293
Chapter 10 Security, Network Applications, and Distributed Systems 295 Chapter Objectives 295 Security 296
Vendor-Provided Security 296
Physical Security 297
Passwords 301
Recognizing Unauthorized Access Attempts 304
Automatic Logoff 304
Transaction Logs 305
Workgroup Software 306
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Duplicated Databases and Inconsistent Data 325 Centralization 325 Disadvantages of Centralization 327
Networked Systems 327 Distributed File Systems 318
Client/Server Computing 329
C/S Technology 324
Advantages 327
Summary 329