Next Generation and Advanced Network Reliability Analysis (eBook)

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.

Preface 7
Acknowledgments 8
Contents 9
List of Figures 16
List of Tables 22
Chapter 1: Next-Generation Network (NGN) 24
1.1 Introduction 25
1.2 Current Architecture 26
1.2.1 Circuit-Switched Network Versus Packet-Switched Network 27
1.2.2 Evolution of Voice and Data Switching 28
1.2.3 Evolution of Signaling and Gateways 31
1.2.4 Typical Network Architectures 36
1.2.4.1 Typical Fixed Network 36
1.2.4.2 Typical Packet Network 37
1.2.4.3 Typical Wireless Network 37
1.3 Convergence to NGN 39
1.4 NGN Architectures 40
1.5 NGN Building Blocks 41
1.5.1 NGN Architecture Layout 43
1.5.1.1 Basic NGN Protocols 44
1.5.1.2 Interfaces 45
1.5.2 IP Multimedia Architecture Using Softswitch 46
1.6 Quality of Service (QoS) and Quality of Service Experience (QoSE) 47
1.6.1 Quality of Service (QoS) 47
1.6.1.1 QoS Requirements of User/Customer (QoSR) 48
1.6.1.2 QoS Offered/Planned by Service Provider (QoSO) 48
1.6.1.3 QoS Delivered/Achieved by Service Provider (QoSD) 48
1.6.2 Quality of Service for NGN 48
1.6.2.1 Guaranteed QoS 49
1.6.2.2 Relative QoS 49
1.7 Summary 50
References 50
Chapter 2: Hardware Reliability Modeling 51
2.1 Introduction 51
2.2 Need for Analysis 51
2.3 Reliability Techniques 52
2.3.1 Definitions 52
2.3.1.1 5 Nines Calculation 54
2.3.1.2 Annualized Failure Rate 54
2.3.1.3 Component Level Failure Rates 55
2.3.1.4 Device-Level Failure Rates 56
2.3.2 Reliability Improvement 57
2.3.2.1 Reliability Growth Model 58
2.3.3 Reliability Block Diagram and Fault Tree Analysis 59
2.3.3.1 Reliability Block Diagram Generation: Example 61
2.3.4 Markov Modeling for Reliability 62
2.3.4.1 Transition State Reduction 64
2.3.5 Manual Methods for Solving Markov Models 65
2.3.5.1 Flow Rate Solution 66
2.3.6 Automated Solution of Markov Chains 66
2.3.6.1 GTH Algorithm 67
2.3.7 Failure Modeling using Markov 68
2.3.7.1 Coverage Failure Mode 69
2.3.7.2 Detection Failure Mode 69
2.3.7.3 Diagnostic Failure 71
2.3.7.4 Recovery Failure 72
2.3.7.5 Silent Failure Mode Modeling 74
2.3.7.6 Sensitivity Analysis 76
2.4 Summary 78
References 79
Chapter 3: Software Reliability Analysis 80
3.1 Introduction 80
3.2 Scope 80
3.3 Need for Analysis 81
3.4 Software Reliability Engineering (SRE) Basic Concepts 81
3.4.1 Difference Between Hardware Reliability and Software Reliability Assessment Models 84
3.4.2 A High-Level Approach for Improving Software Reliability 85
3.4.3 Life Cycle Phases 86
3.4.3.1 Waterfall Model 87
3.4.3.2 V-Models 89
3.4.3.3 Spiral Model 91
3.4.3.4 Agile Model 93
3.5 Software Quality Assessment 95
3.5.1 Capability Maturity Model Integration (CMMI) 96
3.5.2 ISO Requirements 97
3.5.2.1 ISO 9001:2015 Quality Manage Systems - Requirements 97
3.5.2.2 ISO/IEC 25010:2011 Systems and Software Engineering 97
3.6 SRE Software Reliability Measurement 98
3.6.1 Software Process Tracking Metrics (SPTM) 99
3.6.1.1 Software Size Tracking 99
3.6.1.2 Requirement Traceability Tracking 100
3.6.1.3 Stability Index (Requirements, Design, and Code) Tracking 101
3.6.1.4 Defect Tracking and Correction 102
3.6.1.5 Defect Removal Efficiency Tracking 102
3.6.1.6 Defect Density Tracking 103
3.7 Fault Prevention and Removal 105
3.7.1 Major Fault Categories 105
3.7.2 Sources of Failure 106
3.7.3 Root Cause Analysis 107
3.7.4 Orthogonal Defect Classification 107
3.8 Software Reliability Growth 111
3.8.1 Prediction Models 111
3.8.2 Exponential Model 111
3.8.3 Musa Basic Model 112
3.8.3.1 Poisson Model 112
3.8.3.2 Musa Basic Model 113
3.8.3.3 Comparison Between Musa Basic and Logarithmic Models 114
3.8.3.4 Basic Reliability Estimation Model Summary 116
3.8.3.5 Linear/Weighted Combination of Models 116
3.8.3.6 CASRE Tool 117
3.8.4 Software Markov Models 119
3.8.4.1 Failure and Repair Rate Assumptions 120
3.8.4.2 Initialization 120
3.8.4.3 Software Recovery Manager 120
3.8.4.4 Sensitivity Analysis 123
3.9 Summary 123
References 124
Chapter 4: Software Defined Networking (SDN) 126
4.1 Introduction 126
4.2 Need for Analysis 126
4.3 Defining SDN 127
4.3.1 Application Plane 128
4.3.2 Control Plane 128
4.3.3 Data Plane 128
4.3.4 SDN Architecture Requirements and Scope 128
4.3.5 Key SDN Interfaces 129
4.3.5.1 Northbound Interface 129
4.3.5.2 Southbound Interface 129
4.3.5.3 Eastbound Interface 129
4.3.5.4 Westbound Interface 130
4.3.6 SDN Programmability 130
4.3.7 OpenFlow Switch 130
4.3.8 SDN Data Plane Management 132
4.4 SDN Reliability Analysis 133
4.4.1 Hardware Reliability Analysis of a Hypothetical OpenFlow Controller 138
4.4.2 Analysis 151
4.5 Summary 151
References 151
Chapter 5: Network Function Virtualization 152
5.1 Introduction 152
5.2 Need for Analysis 153
5.3 Defining NFV 153
5.3.1 High-Level NFV Architecture 153
5.3.2 Inter-domain Interfaces (NFV Computing Domain) 156
5.4 NFV Reliability Analysis 157
5.4.1 Single Point of Failure 157
5.4.2 Defining Terminologies for NFV Reliability 158
5.4.3 Multitier Architecture 159
5.4.4 Failure Detection and Recovery 160
5.4.5 I Am Alive Message 162
5.4.6 Timers 162
5.4.7 Reliability Availability and Serviceability (RAS) 162
5.4.7.1 Host Hardware 163
5.4.7.2 Host OS 163
5.4.7.3 Hypervisor 164
5.4.7.4 Applications 164
5.5 Reliability Models 165
5.5.1 Hardware Fault Recovery Model 165
5.5.1.1 Name of Markov Model: NFV_HWR.MODEL 167
5.5.2 Software Recovery Model 168
5.5.2.1 Name of Markov Model: NFV_SWR.MODEL 170
5.5.3 Function Migration Model 170
5.5.3.1 Name of Markov Model: NFV_MIG.MODEL 172
5.5.4 Overload Protection Model 173
5.5.4.1 Name of Markov Model: NFV_OVD.MODEL 175
5.6 Summary of Results 176
5.7 Summary 176
References 177
Chapter 6: Cloud Computing Reliability Analysis 178
6.1 Introduction 178
6.2 Need for Analysis 179
6.3 Defining Cloud Computing 179
6.3.1 Cloud Computing Essential Characteristics 179
6.3.1.1 Software-as-a-Service 180
6.3.1.2 Platform-as-a-Service 181
6.3.1.3 Infrastructure-as-a-Service 181
6.4 Server Virtualization 183
6.4.1 Hypervisors 184
6.4.2 Virtual States 185
6.4.3 Transition States 185
6.4.3.1 VM Markov Transition Model 188
6.4.4 VM Recovery Mechanisms 189
6.4.4.1 VM Snapshot 190
6.4.5 VM Cloning 190
6.5 Cloud Failover 190
6.5.1 Markov Model for Cloud Failover 191
6.6 Container Virtualization 192
6.7 Data Center Computing Environment 192
6.8 Reliability Analysis of VoIP in Cloud Environment 193
6.8.1 Hardware Redundancy and Load Sharing 195
6.8.2 Cloud Load Balancing (1:1 Redundant) 195
6.8.2.1 Markov Model for Load Balancing and Recovery 196
6.8.3 Network Access and Network-Attached Storage (NAS) 198
6.8.3.1 Markov Model Network (1000 + 100 Load Sharing) 198
6.8.4 Storage Array 199
6.8.5 Markov Model for NAS (100 + 10 Load Sharing) 199
6.8.6 Management Server 200
6.8.7 Markov Model for Management Server (1 + 1 Load Sharing) 200
6.8.8 Softswitch 202
6.8.9 SIP Server (1:1 Redundant) 205
6.9 Software Redundancy 206
6.9.1 Software Recovery 207
6.10 Summary 208
References 208
Chapter 7: Next-Generation Transport System 209
7.1 Introduction 209
7.2 Need for Analysis 210
7.3 NGN Transport 210
7.4 Optical Transport Network (OTN) 211
7.4.1 BPON 212
7.4.2 GPON 212
7.4.3 EPON 212
7.4.4 WDM-PON 213
7.5 Optical Network Downtime Categories 213
7.6 Reliability Analysis of Optical Line Unit (OLT) 214
7.7 Reliability Analysis of Optical Network Unit (ONU) 216
7.8 SONET/SDH 218
7.8.1 SONET Rings 219
7.8.2 Path Switching 220
7.8.3 Line Switching 220
7.8.4 Unidirectional vs. Bidirectional Optical Rings 221
7.8.5 Add/Drop Multiplexers 222
7.8.6 Bidirectional Optical Ring with Add/Drop Multiplexers 222
7.9 Markov Model of Protected WDM Ring 224
7.10 Casual Analysis of Fiber Downtimes 227
7.11 Summary 228
References 229
Chapter 8: Reliability Analysis of VoIP System 230
8.1 Introduction 230
8.2 Need for Analysis 231
8.3 Fundamental VoIP Telephone System Hardware Components 232
8.3.1 Softswitches 232
8.3.2 VoIP Call Types 233
8.3.2.1 Calls Based on H.323 Protocol 233
8.3.2.2 Calls Based on SIP Protocol 234
8.3.2.3 VoIP Calls from IP PBX 234
8.3.2.4 VoIP Calls from PSTN 235
8.3.2.5 VoIP Calls from Mobile Phones 235
8.3.3 VoIP Call Features 235
8.3.3.1 Speed Calling 235
8.3.3.2 Call Waiting 235
8.3.3.3 Three-Way Calling 236
8.3.3.4 Call Parking 236
8.3.3.5 Call Transfer 236
8.3.3.6 Voicemail Forwarding 236
8.3.3.7 Call Blocking 236
8.3.3.8 Emergency Calling 237
8.4 Fundamental VoIP Telephone System Software Components 237
8.4.1 Protocols 237
8.4.1.1 IP 237
8.4.1.2 TCP 238
8.4.1.3 UDP 239
8.4.1.4 RTP 239
8.4.1.5 RIP 240
8.4.1.6 OSPF 240
8.4.1.7 EGP 240
8.4.1.8 BGP 240
8.4.1.9 SIP 240
8.4.1.10 H.323 241
8.4.1.11 Q.931 241
8.4.1.12 RSVP 241
8.4.2 Quality of Service for VoIP 241
8.4.2.1 IntServ 242
8.4.2.2 DiffServ 242
8.5 VoIP Voice Quality 242
8.5.1 Methods for Evaluating Voice Quality (PESQ vs. MOS) 244
8.5.1.1 PESQ (Objective Methodology) 244
8.5.1.2 MOS (Subjective Methodology) 245
8.5.1.3 User Quality Perception 247
8.6 SIP Server Hardware Reliability Analysis 249
8.6.1 A Typical Server 250
8.6.1.1 Reliability Block Diagram (RBD) 251
8.6.1.2 Markov Model Fan 252
8.6.1.3 Markov Model Power Supply 253
8.6.1.4 Markov Model Hard Drive (2:2 Redundant) 254
8.6.1.5 Markov Model CPU + Memory (1:1 Redundant) 256
8.6.1.6 Markov Model Ethernet Card (1:1 Redundant) 257
8.6.1.7 Markov Models Motherboard, IO Controller, Video Card, and RAID Controller (Simplex) 259
8.6.2 Summary of Result 260
8.6.3 Reliability Architecture for a Duplex SIP Server 261
8.7 Summary 262
References 263
Chapter 9: Reliability Analysis of Wireless Systems 264
9.1 Introduction 264
9.2 Need for Analysis 265
9.3 Wireless Call and Data Processing 265
9.4 Cellular System 265
9.4.1 Area of Coverage 266
9.4.2 Cellular Coverage 266
9.4.3 Cellular Transmission 268
9.4.4 Multiple Access Principles: TDMA, FDMA, CDMA, and SDMA 269
9.4.4.1 TDMA 269
9.4.4.2 FDMA 269
9.4.4.3 CDMA 269
9.4.4.4 SDMA 269
9.4.4.5 MIMO 270
9.4.4.6 OFDM 270
9.4.5 Evolution of Cellular Technologies 270
9.4.6 CDMA2000 System 271
9.4.7 Enhanced Data Rates for GSM Evolution (EDGE) 272
9.4.8 Evolved High-Speed Packet Access (HSPA+) 272
9.4.9 Long-Term Evolution (4G LTE) 272
9.4.10 5G Wireless 272
9.5 Global System for Mobile Communications (GSM) 273
9.6 General Packet Radio Service (GPRS) 274
9.7 Universal Mobile Telecommunication System (UMTS) 275
9.8 Reliability Analysis of Wireless System 276
9.8.1 Integrated Mobile PSTN Switch 276
9.8.2 Redundant Model for the Central Processor (CP) 277
9.8.3 Switching Processor Analysis with Hot Standby 278
9.8.3.1 Markov State Transition Diagram (CP) 279
9.8.3.2 Markov State Transition Diagram (SP) 280
9.8.4 Base Transceiver Station (BTS) 281
9.8.5 BTS Coverage Analysis 281
9.8.5.1 Downtime Analysis for BTS 1 282
9.8.5.2 Downtime Analysis for BTS 2 283
9.8.5.3 Downtime Analysis for BTS 3 283
9.8.5.4 Downtime Analysis for BTS 4 283
9.8.5.5 Reliability Block Diagram (RBD) of BTS 289
9.9 Summary 294
References 294
Chapter 10: Reliability Testing for Advanced Networks 295
10.1 Introduction 295
10.2 Need for Analysis 296
10.2.1 High-Level Test Flow 296
10.2.2 Test Documentation 297
10.2.2.1 Test Plan 297
10.2.2.2 Test Case 297
10.2.2.3 Test Script 298
10.2.2.4 Test Data 298
10.2.3 Basic Test Metrics 298
10.2.4 Unit Test 299
10.2.5 Integration Test 300
10.2.6 Subsystem Test 300
10.2.7 System Test 300
10.2.8 Stress Testing 301
10.2.9 Scalability Testing 301
10.2.10 Performance Testing 302
10.2.11 System Recovery 302
10.2.12 Regression Test 303
10.2.13 Acceptance Test 303
10.2.14 Alpha Test 304
10.2.15 Beta Test 304
10.2.16 Deployment 304
10.3 Fault Tolerance 304
10.3.1 Redundancy for Fault Tolerance 305
10.3.2 Minimum Test Plan Requirements for Fault Tolerance 306
10.3.3 Software Fault Tolerance for Software-Defined Networks 307
10.3.4 Software Fault Tolerance for Cloud Applications 308
10.3.4.1 Rejuvenation 308
10.3.5 Adaptive Fault Tolerance in Cloud Environment 310
10.3.5.1 Components of Adjudicator Node 311
10.4 Fault Injected Testing 313
10.4.1 Hardware Fault Injection 313
10.4.1.1 Advantages of Fault Injection in Hardware 313
10.4.1.2 Disadvantages of Fault Injection in Hardware 314
10.4.2 Software Fault Injection 314
10.4.2.1 Advantages of Fault Injection in Software 314
10.4.2.2 Disadvantages of Fault Injection in Software 314
10.5 Operational Profile 316
10.5.1 Profile Probabilities 316
10.5.2 Operational Profile 316
10.5.2.1 Customer-Type List 317
10.5.2.2 User-Type List 317
10.5.2.3 System Mode List 317
10.5.3 Functional Profile 317
10.5.3.1 Implicit vs Explicit Functions 318
10.5.3.2 Frequency of Occurrence 318
10.5.4 Test Case Selection 319
10.6 Summary 321
References 321
Index 323