Elastic Optical Networks (eBook)

Dr. Lopez is a Technology Expert at Telefonica Global CTO units. He works on the IP and optical processes of the Telefonica group as well as in the research projects funded by the Telefonica group and the European Commission. He has wide experience from telecom industry to academe in his ten years career. He has co-authored more than 100 publications and contributed to IETF drafts. Dr. Velasco had devoted more than 25 years in the telecommunications industry for advanced research, development and deployment of optical networks. His recent research efforts at Universitat Politecnica de Catalunya have been focusing on network planning. He has co-authored more than 130 peer-reviewed journals and conference papers. He has served in the technical program committee of Optical Fiber Communications (OFC) conference and is currently serving as an associate editor of IEEE/OSA Journal of Optical Communications and Networking. 

Contents 6
Chapter 1: Motivation 8
1.1 Bandwidth Variable Transponders 11
1.2 Flexgrid 11
1.2.1 Structure of the book 12
Chapter 2: Evolution from Wavelength-Switched to Flex-­Grid Optical Networks 13
2.1 Introduction 14
2.2 The History of ITU Grids and Development from Fixed to Flex-Grid 14
2.3 Point-to-Point Fixed-Grid DWDM Architectures 16
2.4 WSS Technology: Fixed and Flex 18
2.5 ROADM Architectures 20
2.6 Performance of Fixed and Flex-Grid Networks 22
2.7 Migration to Flex-Grid 26
2.8 Metro/Core Network Architecture 29
2.9 Concluding Remarks 33
References 34
Chapter 3: Taking Advantage of Elastic Optical Networks 37
3.1 Introduction 38
3.1.1 Flex-Grid vs. EON 38
3.1.2 Demystifying EONs 39
3.2 Advanced Networking Features Exploiting Flex-Grid 44
3.2.1 Multi-layer Resilience in General 44
Case 1: Multi-layer Resilience Based on Elastic Flex-Rate Transceivers 46
Case 2: Transceiver Sliceability for Multi-layer Resilience 46
3.3 Flex-Grid in Metro-Regional Networks: Serving Traffic to BRAS Servers 48
3.4 Multi-layer Network Planning for Cost and Energy Minimization 51
3.5 Interconnecting Data Centres 53
3.5.1 Motivation 53
3.5.2 Dynamic Connection Requests 54
3.5.3 Transfer Mode Requests 57
3.6 Concluding Remarks 59
References 59
Chapter 4: Routing and Spectrum Allocation 61
4.1 Introduction 62
4.2 Basic Offline Planning Problems 63
4.2.1 Basic Concepts 63
4.2.2 Basic RSA Problem 64
4.2.3 Topology Design as a RSA Problem 66
4.2.4 Network Dimensioning as a RSA Problem 68
4.3 Solving Techniques 68
4.3.1 Large-Scale Optimization 69
4.3.2 Metaheuristics 70
4.3.3 RSA Algorithm for Single Demands 72
4.4 Use Case I: Tunable Transponders and Physical Layer Considerations 72
4.5 Use Case II: Gradual Network Design Problem 75
4.5.1 Problem Statement 76
4.5.2 Mathematical Model 76
4.5.3 Path Generation Algorithm 78
4.5.4 BRKGA Heuristic 80
4.6 Use Case III: Elastic Bandwidth Provisioning 81
4.6.1 Spectrum Allocation Policies 82
4.6.2 Spectrum Expansion/Contraction Policies 84
Concluding Remarks 85
References 86
Chapter 5: Transmission in Elastic Optical Networks 88
5.1 Introduction 89
5.2 System Impairments and Their Mitigation 92
5.2.1 System Impairments 93
Transmitter Impairments 93
Channel Impairments 94
Receiver Impairments 95
5.2.2 Digital Signal Processing for EONs 96
Digital Signal Processing Architectures 96
Blind DSP Architectures 97
Data-Aided DSP Architectures 97
Digital Signal Processing at the Transmitter 98
Impact of Component Quality on the System Performance 98
Advanced Digital Pre-compensation Techniques 99
5.2.3 Digital Signal Processing at the Receiver 101
Spectral Inversion 101
Digital Back-Propagation 102
Radio-Frequency—Pilot Tone 104
5.2.4 Compensation of ROADMs Cascade Through Optical Pre-emphasis 105
5.3 Next-Generation Bandwidth-Variable Transponders 106
5.3.1 Adaptive Choice of Modulation Format 108
5.3.2 Rate-Adaptive Coded Modulation 109
5.3.3 Generation and Multiplexing of Super-Channels 110
5.4 Outlook and Roadmap 113
5.5 Conclusions 114
References 116
Chapter 6: Node Architectures for Elastic and Flexible Optical Networks 122
6.1 Introduction 123
6.2 Requirements, Design Rules, and Criteria for Next Generation Flexible Optical Nodes 124
6.2.1 Literature Review on Legacy Architecture 124
6.2.2 Key Enabling Technologies 126
Wavelength Selective Switches 126
(Sliceable) Bandwidth Variable Transponders 126
Multicasting Switch 127
6.2.3 Design Rules 127
Flexibility 127
Reconfiguration 128
Colorless, Directionless, and Contentionless 128
Scalability: Modularity 129
Resilience 129
6.2.4 Performance Criteria 129
Capacity/Throughput 129
Switching Granularity 130
Physical Performance 130
6.3 Bypass/Express Node Architectures 131
6.3.1 Express Switch Architectures 131
Brief History of OXC Development 131
OXC Evolution 133
Impact of Intra-node Blocking on the Design of Large Port-Count OXCs 135
Architectures for Creating Large Port-Count OXCs [22, 23] 136
Hierarchical Multi-granular Routing [24] 136
Grouped Routing and ? Selective Add/Drop [30] 137
Multi-granular Two-Stage Switching [32, 33] 139
Interconnected Subsystem Architecture [34–36] 139
6.4 Multi-layer Elastic and Flexible Add/Drop Node Architecture 141
6.4.1 Node Architectures and Interfaces That Address Different Multi-layer Use Cases 141
Sub-port Level Grooming 148
Port-Level Grooming 149
Wavelength Level Grooming 149
6.5 Multidimensional and Function Programmable Optical Node Architectures 149
6.5.1 Dimensions for Future Optical Nodes 149
6.5.2 Need for Multidimensionality in Future Optical Nodes 151
AoD Node Functionality and Operation 152
Scalability 153
Bandwidth Granularity and Adaptability 154
6.5.3 Optical Network Function Programmability 155
Node Level Synthesis and Programmability 155
Function Programmable OXCs 156
Optical Layer NFP 157
6.6 Summary 159
References 160
Chapter 7: Sliceable Bandwidth Variable Transponders 163
7.1 Introduction 164
7.2 Sliceable Bandwidth Variable Transponder Architectures 165
7.2.1 S-BVT Requirements 165
7.2.2 S-BVT Architecture 165
Flex Sub-Carrier Module 167
Sub-Carrier Generator Module 167
7.2.3 Example of an S-BVT Supporting 400 Gb/s 169
7.2.4 Component Technologies, Complexity, and Integration 172
7.2.5 S-BVT Programmability Perspectives 173
7.3 S-BVT Architectures Involving Multiple Layers 174
7.3.1 IP Layer Architectures Without S-BVT 175
7.3.2 How Does S-BVT Enable a Better IP Layer Architecture? 177
7.3.3 How to Interconnect Routers and S-BVTs 178
7.4 Network Planning Process Using S-BVTs 180
7.4.1 Network Planning Example 180
7.4.2 Mixed Integer Linear Programming Definition 181
7.5 Expected Savings from S-BVTs 184
7.5.1 Scenario Definition 184
7.5.2 Impact on the Number of Transponders 185
7.5.3 Impact on IP Layer Networks 186
7.5.4 Total CAPEX Savings of S-BVTs 188
7.6 Conclusions 190
References 191
Chapter 8: GMPLS Control Plane 193
8.1 Introduction to Control Plane Functionalities 195
8.1.1 Protocols 196
8.2 GMPLS Control Plane Architecture 197
8.2.1 Introduction to the GMPLS/PCE Architecture 197
8.2.2 Signalling (RSVP-TE) 202
8.2.3 Resource Discovery and Topology Dissemination 204
Introduction to Routing, OSPF-TE and IS-IS-TE 204
BGP-LS 205
BGP-LS Session Establishment 205
Topology Exchange 206
Describing Nodes and Links in BGP-LS 206
8.3 Architecting the Control Plane for EON 207
8.3.1 Extending Signalling for EON 207
8.3.2 Path Computation in Flexi-Grid Networks 209
8.3.3 Resource Discovery 211
8.4 Multi-Domain EON Control Plane GMPLS & H-PCE Architecture
8.4.1 Hierarchical PCE 215
8.4.2 Hierarchical PCE Topology Construction 216
8.4.3 Inter-Domain Signalling 216
8.5 Conclusions 218
References 218
Chapter 9: Software Defined Networking (SDN) in Optical Networks 220
9.1 SDN Architecture 221
9.1.1 General Concepts 221
9.1.2 SDN Logical Partitioning 222
9.2 OpenFlow Protocol 223
9.2.1 Main OpenFlow Messages 225
9.3 SDN for Optical Networks: Reference Architecture 225
9.3.1 Challenges for Transport Network Abstraction 226
9.3.2 Flow Abstraction 227
9.3.3 Drivers 227
9.3.4 Virtualization 228
9.3.5 Northbound Application Layer Abstraction 228
9.3.6 Performance 229
9.4 OpenFlow for Optical Networks: Protocol Extensions 229
9.4.1 Basic OpenFlow Protocol Requirements 230
9.4.2 OpenFlow for Optical Circuit Switching 231
9.4.3 OpenFlow for Optical Transceiver Configuration and Monitoring 232
9.4.4 OpenFlow for Optical Burst and Packet Switching 233
9.5 NETCONF Protocol 234
9.5.1 Configuration of Packet Switches 234
9.5.2 Configuration of Optical Nodes 236
9.6 Examples and Use Cases 238
9.6.1 Use Case I: Restoration 238
Bitrate Squeezing and Multipath Restoration 238
The Bitrate Squeezing and Multipath Restoration Problem Statement 239
Example of SDN Implementation Supporting BATIDO 240
Evaluation on Recovery Time 241
9.6.2 Use Case II: Filter Configuration Optimization 242
Proposed Super-Filter Technique 242
Super-Filter Implementation, OpenFlow Extensions, and Experimental Demonstration 244
9.7 Conclusions 245
References 245
Chapter 10: Application-Based Network Operations (ABNO) 248
10.1 General Concepts 249
10.2 Network Abstraction 249
10.2.1 Logically Centralized Control 249
10.2.2 Application-Driven Use-Cases 250
10.3 Network Control 251
10.3.1 Control Plane 252
10.3.2 Management Plane 253
10.3.3 Control Elements for Operating Optical Networks 255
Path Computation 255
Service Provisioning 255
OAM and Performance Monitoring 255
10.4 Distributed and Centralized Control Planes 256
10.4.1 Control Plane Architecture Evolution 256
Distributed Control 257
Centralized Control 258
Comparison of Distributed Versus Centralized 259
Hybrid Control Plane Models 259
10.5 Framework for Application-Based Network Operations 261
10.5.1 Functional Components 261
NMS and OSS 261
Application Service Coordinator 262
ABNO Controller 263
Policy Agent 263
OAM Handler 263
Path Computation Element 263
Network Database 264
Virtual Network Topology Manager 264
Provisioning Manager 265
10.5.2 South Bound Interfaces 265
10.6 Adaptive Network Manager 265
10.6.1 Interfaces 266
10.7 Adaptive Network Manager Use-Cases 267
10.7.1 Catastrophic Network Failure 267
10.8 Next Steps for ABNO-Based Control and Orchestration 268
10.8.1 Control and Orchestration of Virtual Content Distribution Network 269
References 270
Chapter 11: In-Operation Network Planning 271
11.1 Towards In-operation Network Planning 273
11.1.1 Drivers and Motivations for In-operation Network Planning 273
11.1.2 Migration Towards In-operation Network Planning 274
11.2 Architectures to Support In-operation Planning 276
11.2.1 Requirements to Support In-operation Planning 276
11.2.2 Existing Approaches for In-operation Network Planning 278
Reactive In-operation Planning 278
Periodic Planning 279
Preventive Planning 279
11.2.3 Relationship with the Control Plane 280
The Front-End/Back-End Architecture 280
Stateless PCE with GCO and ABNO 281
11.3 Main Use Cases 282
11.3.1 Use Case I: Virtual Network Topology Reconfiguration 282
11.3.2 Use Case II: Spectrum Defragmentation 285
11.3.3 Use Case III: After Failure Repair Re-optimization 289
11.4 Conclusions 293
References 293
Index 295