Ali Next Generation and Advanced Network Reliability Analysis

Using Markov Models and Software Reliability Engineering
1. Auflage 2018
ISBN: 978-3-030-01647-0
Verlag: Springer International Publishing
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 329 Seiten

Reihe: Signals and Communication Technology

This book covers reliability assessment and prediction of new technologies such as next generation networks that use cloud computing, Network Function Virtualization (NVF), Software Defined Network (SDN), Next Generation Transport, Evolving Wireless Systems, Digital VoIP Telephony, and Reliability Testing techniques specific to Next Generation Networks (NGN). This book introduces the technology to the reader first, followed by advanced reliability techniques applicable to both hardware and software reliability analysis. The book covers methodologies that can predict reliability using component failure rates to system level downtimes. The book's goal is to familiarize the reader with analytical techniques, tools and methods necessary for analyzing very complex networks using very different technologies. The book lets readers quickly learn technologies behind currently evolving NGN and apply advanced Markov modeling and Software Reliability Engineering (SRE) techniques for assessing their operational reliability.Covers reliability analysis of advanced networks and provides basic mathematical tools and analysis techniques and methodology for reliability and quality assessment;
Develops Markov and Software Engineering Models to predict reliability;
Covers both hardware and software reliability for next generation technologies.



Syed R. Ali, DEE, is currently CEO and Principal of Software Reliability Research, LLC conducting upfront research and consultation with sophisticated software tools and methodologies for companies and organizations that seek state-of-the-art reliability analysis of their products and services for Next Generation Networks (NGN), Virtualized Networks, emerging wireless and other technologies. The objective of his organization is to provide high reliability framework for assessing and measuring overall operational end-to-end reliability of complex real-time mission critical systems. Syed was principal consultant at Bell Communications Research for over 30 years and was instrumental in setting up industry wide metrics was measuring software quality at all life cycle phases. He pioneered the concept of software fault insertion techniques for increasing software reliability before its released. While at Telcordia (formerly Bellcore) he developed Telcordia's In-Process Quality Metrics (IPQM, GR-1315), Object Oriented Process Metrics (OOPM, SR-4047), and contributed to many IEEE and ISO standards.  He is author of book 'Digital Switching Systems -System Reliability Analysis published by McGraw-Hill, 1997, ISBN 0-07-001069-2. Syed is an expert in the field with extensive experience in analyzing reliability of advanced network architectures around the world.  He has consulted with Ericcson (Sweden), Nortel (Canada), Siemens (Germany), NEC (Japan), Alcatel, (France), Singtel (Singapore), and Fujitsu (Japan) and has supported many international standard bodies. Syed is the past chairperson of IEEE Communications and co-founder of Computer Society New York Section.   He is a frequent speaker at many IEEE and international telecommunications forums and is regarded as a leader in the field of reliability. Syed received his BSEE from Bangladesh University of Engineering & Technology (BUET), MSEE from Tuskegee University, Tuskegee Alabama and DEE from New Jersey Institute of Technology, Newark, NJ.

Autoren/Hrsg.

Ali, Syed Riffat

Inhaltsverzeichnis

1;Preface;7
2;Acknowledgments;8
3;Contents;9
4;List of Figures;16
5;List of Tables;22
6;Chapter 1: Next-Generation Network (NGN);24
6.1;1.1 Introduction;25
6.2;1.2 Current Architecture;26
6.2.1;1.2.1 Circuit-Switched Network Versus Packet-Switched Network;27
6.2.2;1.2.2 Evolution of Voice and Data Switching;28
6.2.3;1.2.3 Evolution of Signaling and Gateways;31
6.2.4;1.2.4 Typical Network Architectures;36
6.2.4.1;1.2.4.1 Typical Fixed Network;36
6.2.4.2;1.2.4.2 Typical Packet Network;37
6.2.4.3;1.2.4.3 Typical Wireless Network;37
6.3;1.3 Convergence to NGN;39
6.4;1.4 NGN Architectures;40
6.5;1.5 NGN Building Blocks;41
6.5.1;1.5.1 NGN Architecture Layout;43
6.5.1.1;1.5.1.1 Basic NGN Protocols;44
6.5.1.2;1.5.1.2 Interfaces;45
6.5.2;1.5.2 IP Multimedia Architecture Using Softswitch;46
6.6;1.6 Quality of Service (QoS) and Quality of Service Experience (QoSE);47
6.6.1;1.6.1 Quality of Service (QoS);47
6.6.1.1;1.6.1.1 QoS Requirements of User/Customer (QoSR);48
6.6.1.2;1.6.1.2 QoS Offered/Planned by Service Provider (QoSO);48
6.6.1.3;1.6.1.3 QoS Delivered/Achieved by Service Provider (QoSD);48
6.6.2;1.6.2 Quality of Service for NGN;48
6.6.2.1;1.6.2.1 Guaranteed QoS;49
6.6.2.2;1.6.2.2 Relative QoS;49
6.7;1.7 Summary;50
6.8;References;50
7;Chapter 2: Hardware Reliability Modeling;51
7.1;2.1 Introduction;51
7.2;2.2 Need for Analysis;51
7.3;2.3 Reliability Techniques;52
7.3.1;2.3.1 Definitions;52
7.3.1.1;2.3.1.1 5 Nines Calculation;54
7.3.1.2;2.3.1.2 Annualized Failure Rate;54
7.3.1.3;2.3.1.3 Component Level Failure Rates;55
7.3.1.4;2.3.1.4 Device-Level Failure Rates;56
7.3.2;2.3.2 Reliability Improvement;57
7.3.2.1;2.3.2.1 Reliability Growth Model;58
7.3.3;2.3.3 Reliability Block Diagram and Fault Tree Analysis;59
7.3.3.1;2.3.3.1 Reliability Block Diagram Generation: Example;61
7.3.4;2.3.4 Markov Modeling for Reliability;62
7.3.4.1;2.3.4.1 Transition State Reduction;64
7.3.5;2.3.5 Manual Methods for Solving Markov Models;65
7.3.5.1;2.3.5.1 Flow Rate Solution;66
7.3.6;2.3.6 Automated Solution of Markov Chains;66
7.3.6.1;2.3.6.1 GTH Algorithm;67
7.3.7;2.3.7 Failure Modeling using Markov;68
7.3.7.1;2.3.7.1 Coverage Failure Mode;69
7.3.7.2;2.3.7.2 Detection Failure Mode;69
7.3.7.3;2.3.7.3 Diagnostic Failure;71
7.3.7.4;2.3.7.4 Recovery Failure;72
7.3.7.5;2.3.7.5 Silent Failure Mode Modeling;74
7.3.7.6;2.3.7.6 Sensitivity Analysis;76
7.4;2.4 Summary;78
7.5;References;79
8;Chapter 3: Software Reliability Analysis;80
8.1;3.1 Introduction;80
8.2;3.2 Scope;80
8.3;3.3 Need for Analysis;81
8.4;3.4 Software Reliability Engineering (SRE) Basic Concepts;81
8.4.1;3.4.1 Difference Between Hardware Reliability and Software Reliability Assessment Models;84
8.4.2;3.4.2 A High-Level Approach for Improving Software Reliability;85
8.4.3;3.4.3 Life Cycle Phases;86
8.4.3.1;3.4.3.1 Waterfall Model;87
8.4.3.2;3.4.3.2 V-Models;89
8.4.3.3;3.4.3.3 Spiral Model;91
8.4.3.4;3.4.3.4 Agile Model;93
8.5;3.5 Software Quality Assessment;95
8.5.1;3.5.1 Capability Maturity Model Integration (CMMI);96
8.5.2;3.5.2 ISO Requirements;97
8.5.2.1;3.5.2.1 ISO 9001:2015 Quality Manage Systems - Requirements;97
8.5.2.2;3.5.2.2 ISO/IEC 25010:2011 Systems and Software Engineering;97
8.6;3.6 SRE Software Reliability Measurement;98
8.6.1;3.6.1 Software Process Tracking Metrics (SPTM);99
8.6.1.1;3.6.1.1 Software Size Tracking;99
8.6.1.2;3.6.1.2 Requirement Traceability Tracking;100
8.6.1.3;3.6.1.3 Stability Index (Requirements, Design, and Code) Tracking;101
8.6.1.4;3.6.1.4 Defect Tracking and Correction;102
8.6.1.5;3.6.1.5 Defect Removal Efficiency Tracking;102
8.6.1.6;3.6.1.6 Defect Density Tracking;103
8.7;3.7 Fault Prevention and Removal;105
8.7.1;3.7.1 Major Fault Categories;105
8.7.2;3.7.2 Sources of Failure;106
8.7.3;3.7.3 Root Cause Analysis;107
8.7.4;3.7.4 Orthogonal Defect Classification;107
8.8;3.8 Software Reliability Growth;111
8.8.1;3.8.1 Prediction Models;111
8.8.2;3.8.2 Exponential Model;111
8.8.3;3.8.3 Musa Basic Model;112
8.8.3.1;3.8.3.1 Poisson Model;112
8.8.3.2;3.8.3.2 Musa Basic Model;113
8.8.3.3;3.8.3.3 Comparison Between Musa Basic and Logarithmic Models;114
8.8.3.4;3.8.3.4 Basic Reliability Estimation Model Summary;116
8.8.3.5;3.8.3.5 Linear/Weighted Combination of Models;116
8.8.3.6;3.8.3.6 CASRE Tool;117
8.8.4;3.8.4 Software Markov Models;119
8.8.4.1;3.8.4.1 Failure and Repair Rate Assumptions;120
8.8.4.2;3.8.4.2 Initialization;120
8.8.4.3;3.8.4.3 Software Recovery Manager;120
8.8.4.4;3.8.4.4 Sensitivity Analysis;123
8.9;3.9 Summary;123
8.10;References;124
9;Chapter 4: Software Defined Networking (SDN);126
9.1;4.1 Introduction;126
9.2;4.2 Need for Analysis;126
9.3;4.3 Defining SDN;127
9.3.1;4.3.1 Application Plane;128
9.3.2;4.3.2 Control Plane;128
9.3.3;4.3.3 Data Plane;128
9.3.4;4.3.4 SDN Architecture Requirements and Scope;128
9.3.5;4.3.5 Key SDN Interfaces;129
9.3.5.1;4.3.5.1 Northbound Interface;129
9.3.5.2;4.3.5.2 Southbound Interface;129
9.3.5.3;4.3.5.3 Eastbound Interface;129
9.3.5.4;4.3.5.4 Westbound Interface;130
9.3.6;4.3.6 SDN Programmability;130
9.3.7;4.3.7 OpenFlow Switch;130
9.3.8;4.3.8 SDN Data Plane Management;132
9.4;4.4 SDN Reliability Analysis;133
9.4.1;4.4.1 Hardware Reliability Analysis of a Hypothetical OpenFlow Controller;138
9.4.2;4.4.2 Analysis;151
9.5;4.5 Summary;151
9.6;References;151
10;Chapter 5: Network Function Virtualization;152
10.1;5.1 Introduction;152
10.2;5.2 Need for Analysis;153
10.3;5.3 Defining NFV;153
10.3.1;5.3.1 High-Level NFV Architecture;153
10.3.2;5.3.2 Inter-domain Interfaces (NFV Computing Domain);156
10.4;5.4 NFV Reliability Analysis;157
10.4.1;5.4.1 Single Point of Failure;157
10.4.2;5.4.2 Defining Terminologies for NFV Reliability;158
10.4.3;5.4.3 Multitier Architecture;159
10.4.4;5.4.4 Failure Detection and Recovery;160
10.4.5;5.4.5 I Am Alive Message;162
10.4.6;5.4.6 Timers;162
10.4.7;5.4.7 Reliability Availability and Serviceability (RAS);162
10.4.7.1;5.4.7.1 Host Hardware;163
10.4.7.2;5.4.7.2 Host OS;163
10.4.7.3;5.4.7.3 Hypervisor;164
10.4.7.4;5.4.7.4 Applications;164
10.5;5.5 Reliability Models;165
10.5.1;5.5.1 Hardware Fault Recovery Model;165
10.5.1.1;5.5.1.1 Name of Markov Model: NFV_HWR.MODEL;167
10.5.2;5.5.2 Software Recovery Model;168
10.5.2.1;5.5.2.1 Name of Markov Model: NFV_SWR.MODEL;170
10.5.3;5.5.3 Function Migration Model;170
10.5.3.1;5.5.3.1 Name of Markov Model: NFV_MIG.MODEL;172
10.5.4;5.5.4 Overload Protection Model;173
10.5.4.1;5.5.4.1 Name of Markov Model: NFV_OVD.MODEL;175
10.6;5.6 Summary of Results;176
10.7;5.7 Summary;176
10.8;References;177
11;Chapter 6: Cloud Computing Reliability Analysis;178
11.1;6.1 Introduction;178
11.2;6.2 Need for Analysis;179
11.3;6.3 Defining Cloud Computing;179
11.3.1;6.3.1 Cloud Computing Essential Characteristics;179
11.3.1.1;6.3.1.1 Software-as-a-Service;180
11.3.1.2;6.3.1.2 Platform-as-a-Service;181
11.3.1.3;6.3.1.3 Infrastructure-as-a-Service;181
11.4;6.4 Server Virtualization;183
11.4.1;6.4.1 Hypervisors;184
11.4.2;6.4.2 Virtual States;185
11.4.3;6.4.3 Transition States;185
11.4.3.1;6.4.3.1 VM Markov Transition Model;188
11.4.4;6.4.4 VM Recovery Mechanisms;189
11.4.4.1;6.4.4.1 VM Snapshot;190
11.4.5;6.4.5 VM Cloning;190
11.5;6.5 Cloud Failover;190
11.5.1;6.5.1 Markov Model for Cloud Failover;191
11.6;6.6 Container Virtualization;192
11.7;6.7 Data Center Computing Environment;192
11.8;6.8 Reliability Analysis of VoIP in Cloud Environment;193
11.8.1;6.8.1 Hardware Redundancy and Load Sharing;195
11.8.2;6.8.2 Cloud Load Balancing (1:1 Redundant);195
11.8.2.1;6.8.2.1 Markov Model for Load Balancing and Recovery;196
11.8.3;6.8.3 Network Access and Network-Attached Storage (NAS);198
11.8.3.1;6.8.3.1 Markov Model Network (1000 + 100 Load Sharing);198
11.8.4;6.8.4 Storage Array;199
11.8.5;6.8.5 Markov Model for NAS (100 + 10 Load Sharing);199
11.8.6;6.8.6 Management Server;200
11.8.7;6.8.7 Markov Model for Management Server (1 + 1 Load Sharing);200
11.8.8;6.8.8 Softswitch;202
11.8.9;6.8.9 SIP Server (1:1 Redundant);205
11.9;6.9 Software Redundancy;206
11.9.1;6.9.1 Software Recovery;207
11.10;6.10 Summary;208
11.11;References;208
12;Chapter 7: Next-Generation Transport System;209
12.1;7.1 Introduction;209
12.2;7.2 Need for Analysis;210
12.3;7.3 NGN Transport;210
12.4;7.4 Optical Transport Network (OTN);211
12.4.1;7.4.1 BPON;212
12.4.2;7.4.2 GPON;212
12.4.3;7.4.3 EPON;212
12.4.4;7.4.4 WDM-PON;213
12.5;7.5 Optical Network Downtime Categories;213
12.6;7.6 Reliability Analysis of Optical Line Unit (OLT);214
12.7;7.7 Reliability Analysis of Optical Network Unit (ONU);216
12.8;7.8 SONET/SDH;218
12.8.1;7.8.1 SONET Rings;219
12.8.2;7.8.2 Path Switching;220
12.8.3;7.8.3 Line Switching;220
12.8.4;7.8.4 Unidirectional vs. Bidirectional Optical Rings;221
12.8.5;7.8.5 Add/Drop Multiplexers;222
12.8.6;7.8.6 Bidirectional Optical Ring with Add/Drop Multiplexers;222
12.9;7.9 Markov Model of Protected WDM Ring;224
12.10;7.10 Casual Analysis of Fiber Downtimes;227
12.11;7.11 Summary;228
12.12;References;229
13;Chapter 8: Reliability Analysis of VoIP System;230
13.1;8.1 Introduction;230
13.2;8.2 Need for Analysis;231
13.3;8.3 Fundamental VoIP Telephone System Hardware Components;232
13.3.1;8.3.1 Softswitches;232
13.3.2;8.3.2 VoIP Call Types;233
13.3.2.1;8.3.2.1 Calls Based on H.323 Protocol;233
13.3.2.2;8.3.2.2 Calls Based on SIP Protocol;234
13.3.2.3;8.3.2.3 VoIP Calls from IP PBX;234
13.3.2.4;8.3.2.4 VoIP Calls from PSTN;235
13.3.2.5;8.3.2.5 VoIP Calls from Mobile Phones;235
13.3.3;8.3.3 VoIP Call Features;235
13.3.3.1;8.3.3.1 Speed Calling;235
13.3.3.2;8.3.3.2 Call Waiting;235
13.3.3.3;8.3.3.3 Three-Way Calling;236
13.3.3.4;8.3.3.4 Call Parking;236
13.3.3.5;8.3.3.5 Call Transfer;236
13.3.3.6;8.3.3.6 Voicemail Forwarding;236
13.3.3.7;8.3.3.7 Call Blocking;236
13.3.3.8;8.3.3.8 Emergency Calling;237
13.4;8.4 Fundamental VoIP Telephone System Software Components;237
13.4.1;8.4.1 Protocols;237
13.4.1.1;8.4.1.1 IP;237
13.4.1.2;8.4.1.2 TCP;238
13.4.1.3;8.4.1.3 UDP;239
13.4.1.4;8.4.1.4 RTP;239
13.4.1.5;8.4.1.5 RIP;240
13.4.1.6;8.4.1.6 OSPF;240
13.4.1.7;8.4.1.7 EGP;240
13.4.1.8;8.4.1.8 BGP;240
13.4.1.9;8.4.1.9 SIP;240
13.4.1.10;8.4.1.10 H.323;241
13.4.1.11;8.4.1.11 Q.931;241
13.4.1.12;8.4.1.12 RSVP;241
13.4.2;8.4.2 Quality of Service for VoIP;241
13.4.2.1;8.4.2.1 IntServ;242
13.4.2.2;8.4.2.2 DiffServ;242
13.5;8.5 VoIP Voice Quality;242
13.5.1;8.5.1 Methods for Evaluating Voice Quality (PESQ vs. MOS);244
13.5.1.1;8.5.1.1 PESQ (Objective Methodology);244
13.5.1.2;8.5.1.2 MOS (Subjective Methodology);245
13.5.1.3;8.5.1.3 User Quality Perception;247
13.6;8.6 SIP Server Hardware Reliability Analysis;249
13.6.1;8.6.1 A Typical Server;250
13.6.1.1;8.6.1.1 Reliability Block Diagram (RBD);251
13.6.1.2;8.6.1.2 Markov Model Fan;252
13.6.1.3;8.6.1.3 Markov Model Power Supply;253
13.6.1.4;8.6.1.4 Markov Model Hard Drive (2:2 Redundant);254
13.6.1.5;8.6.1.5 Markov Model CPU + Memory (1:1 Redundant);256
13.6.1.6;8.6.1.6 Markov Model Ethernet Card (1:1 Redundant);257
13.6.1.7;8.6.1.7 Markov Models Motherboard, IO Controller, Video Card, and RAID Controller (Simplex);259
13.6.2;8.6.2 Summary of Result;260
13.6.3;8.6.3 Reliability Architecture for a Duplex SIP Server;261
13.7;8.7 Summary;262
13.8;References;263
14;Chapter 9: Reliability Analysis of Wireless Systems;264
14.1;9.1 Introduction;264
14.2;9.2 Need for Analysis;265
14.3;9.3 Wireless Call and Data Processing;265
14.4;9.4 Cellular System;265
14.4.1;9.4.1 Area of Coverage;266
14.4.2;9.4.2 Cellular Coverage;266
14.4.3;9.4.3 Cellular Transmission;268
14.4.4;9.4.4 Multiple Access Principles: TDMA, FDMA, CDMA, and SDMA;269
14.4.4.1;9.4.4.1 TDMA;269
14.4.4.2;9.4.4.2 FDMA;269
14.4.4.3;9.4.4.3 CDMA;269
14.4.4.4;9.4.4.4 SDMA;269
14.4.4.5;9.4.4.5 MIMO;270
14.4.4.6;9.4.4.6 OFDM;270
14.4.5;9.4.5 Evolution of Cellular Technologies;270
14.4.6;9.4.6 CDMA2000 System;271
14.4.7;9.4.7 Enhanced Data Rates for GSM Evolution (EDGE);272
14.4.8;9.4.8 Evolved High-Speed Packet Access (HSPA+);272
14.4.9;9.4.9 Long-Term Evolution (4G LTE);272
14.4.10;9.4.10 5G Wireless;272
14.5;9.5 Global System for Mobile Communications (GSM);273
14.6;9.6 General Packet Radio Service (GPRS);274
14.7;9.7 Universal Mobile Telecommunication System (UMTS);275
14.8;9.8 Reliability Analysis of Wireless System;276
14.8.1;9.8.1 Integrated Mobile PSTN Switch;276
14.8.2;9.8.2 Redundant Model for the Central Processor (CP);277
14.8.3;9.8.3 Switching Processor Analysis with Hot Standby;278
14.8.3.1;9.8.3.1 Markov State Transition Diagram (CP);279
14.8.3.2;9.8.3.2 Markov State Transition Diagram (SP);280
14.8.4;9.8.4 Base Transceiver Station (BTS);281
14.8.5;9.8.5 BTS Coverage Analysis;281
14.8.5.1;9.8.5.1 Downtime Analysis for BTS 1;282
14.8.5.2;9.8.5.2 Downtime Analysis for BTS 2;283
14.8.5.3;9.8.5.3 Downtime Analysis for BTS 3;283
14.8.5.4;9.8.5.4 Downtime Analysis for BTS 4;283
14.8.5.5;9.8.5.5 Reliability Block Diagram (RBD) of BTS;289
14.9;9.9 Summary;294
14.10;References;294
15;Chapter 10: Reliability Testing for Advanced Networks;295
15.1;10.1 Introduction;295
15.2;10.2 Need for Analysis;296
15.2.1;10.2.1 High-Level Test Flow;296
15.2.2;10.2.2 Test Documentation;297
15.2.2.1;10.2.2.1 Test Plan;297
15.2.2.2;10.2.2.2 Test Case;297
15.2.2.3;10.2.2.3 Test Script;298
15.2.2.4;10.2.2.4 Test Data;298
15.2.3;10.2.3 Basic Test Metrics;298
15.2.4;10.2.4 Unit Test;299
15.2.5;10.2.5 Integration Test;300
15.2.6;10.2.6 Subsystem Test;300
15.2.7;10.2.7 System Test;300
15.2.8;10.2.8 Stress Testing;301
15.2.9;10.2.9 Scalability Testing;301
15.2.10;10.2.10 Performance Testing;302
15.2.11;10.2.11 System Recovery;302
15.2.12;10.2.12 Regression Test;303
15.2.13;10.2.13 Acceptance Test;303
15.2.14;10.2.14 Alpha Test;304
15.2.15;10.2.15 Beta Test;304
15.2.16;10.2.16 Deployment;304
15.3;10.3 Fault Tolerance;304
15.3.1;10.3.1 Redundancy for Fault Tolerance;305
15.3.2;10.3.2 Minimum Test Plan Requirements for Fault Tolerance;306
15.3.3;10.3.3 Software Fault Tolerance for Software-Defined Networks;307
15.3.4;10.3.4 Software Fault Tolerance for Cloud Applications;308
15.3.4.1;10.3.4.1 Rejuvenation;308
15.3.5;10.3.5 Adaptive Fault Tolerance in Cloud Environment;310
15.3.5.1;10.3.5.1 Components of Adjudicator Node;311
15.4;10.4 Fault Injected Testing;313
15.4.1;10.4.1 Hardware Fault Injection;313
15.4.1.1;10.4.1.1 Advantages of Fault Injection in Hardware;313
15.4.1.2;10.4.1.2 Disadvantages of Fault Injection in Hardware;314
15.4.2;10.4.2 Software Fault Injection;314
15.4.2.1;10.4.2.1 Advantages of Fault Injection in Software;314
15.4.2.2;10.4.2.2 Disadvantages of Fault Injection in Software;314
15.5;10.5 Operational Profile;316
15.5.1;10.5.1 Profile Probabilities;316
15.5.2;10.5.2 Operational Profile;316
15.5.2.1;10.5.2.1 Customer-Type List;317
15.5.2.2;10.5.2.2 User-Type List;317
15.5.2.3;10.5.2.3 System Mode List;317
15.5.3;10.5.3 Functional Profile;317
15.5.3.1;10.5.3.1 Implicit vs Explicit Functions;318
15.5.3.2;10.5.3.2 Frequency of Occurrence;318
15.5.4;10.5.4 Test Case Selection;319
15.6;10.6 Summary;321
15.7;References;321
16;Index;323