Network Programmability with YANG: The Structure of Network Automation with YANG, NETCONF, RESTCONF, and gNMI

Today, networks must evolve and scale faster than ever. You can’t manage everything by hand anymore: You need to automate relentlessly. YANG, along with the NETCONF, RESTCONF, or gRPC/gNMI protocols, is the most practical solution, but most implementers have had to learn by trial and error. Now, Network Programmability with YANG gives you complete and reliable guidance for unlocking the full power of network automation using model-driven APIs and protocols. Authored by three YANG pioneers, this plain-spoken book guides you through successfully applying software practices based on YANG data models. The authors focus on the network operations layer, emphasizing model-driven APIs, and underlying transports. Whether you’re a network operator, DevOps engineer, software developer, orchestration engineer, NMS/OSS architect, service engineer, or manager, this guide can help you dramatically improve value, agility, and manageability throughout your network. Discover the value of implementing YANG and Data Model-Driven Management in your network Explore the layers and components of a complete working solution Build a business case where value increases as your solution grows Drill down into transport protocols: NETCONF, RESTCONF, and gNMI/gRPC See how telemetry can establish a valuable automated feedback loop Find data models you can build on, and evaluate models with similar functionality Understand models, metadata, and tools from several viewpoints: architect, operator, module author, and application developer Walk through a complete automation journey: business case, service model, service implementation, device integration, and operation Leverage the authors’ experience to design successful YANG models and avoid pitfalls

Table of Contents:
Introduction xxii 1 The Network Management World Must Change: Why Should You Care? 2 Introduction 2 The Industry Has Changed: What Are the Trends? 6 Existing Network Management Practices and Related Limitations 24 Data Modeling Is Key for Automation 39 Interview with the Experts 48 Summary 52 References in This Chapter 53 Endnotes 53 2 Data Model—Driven Management 56 The Beginning: A New Set of Requirements 56 Network Management Is Dead, Long Live Network Management 59 YANG: The Data Modeling Language 61 The Management Architecture 69 Data Model—Driven Management Components 70 The Encoding (Protocol Binding and Serialization) 74 The Server Architecture: Datastore 77 The Protocols 78 The Programming Language 85 Telemetry 86 The Bigger Picture: Using NETCONF to Manage a Network 86 Interview with the Experts 91 Summary 93 References in This Chapter 93 Endnotes 94 3 YANG Explained 96 Introduction 96 Describe Your World of Data 96 Describing Possible Events 113 Separating Configuration from Operational Data 117 Constraints Keep Things Meaningful 122 Augmenting, Extending, and Possibly Deviating 142 Network Management Datastore Architecture (NMDA) 149 Interview with the Expert 154 Summary 156 References in This Chapter 157 4 NETCONF, RESTCONF, and gNMI Explained 158 Introduction 158 NETCONF 158 RESTCONF 190 OpenConfig and gNMI 214 Interview with the Expert 225 Summary 227 References in This Chapter 227 5 Telemetry Explained 230 Introduction 230 Data Model—Driven Telemetry 230 Moving Away from SNMP to Telemetry 232 Telemetry Use Cases 235 Telemetry Components 236 Telemetry Standard Mechanisms 242 Interview with the Experts 249 Summary 252 References in This Chapter 253 Endnotes 253 6 YANG Data Modeling Developments in the Industry 256 Introduction 256 The Beginning: The IETF 256 Embracing YANG Throughout the Industry 263 The OpenConfig YANG Model 268 Industry Coordination Is Required 270 Interoperability Testing 272 Implementing More Than One YANG Model for a Specific Functionality 274 Interview with the Expert 275 Summary 278 References in This Chapter 279 Endnotes 279 7 Automation Is as Good as the Data Models, Their Related Metadata, and the Tools: For the Network Architect and Operator 282 Introduction 282 Getting to Know the Structure of a YANG Module 283 Finding the Right Modules Using the YANG Catalog 287 Interacting with Devices 299 Interview with the Experts 331 Summary 335 Endnotes 335 8 Automation Is as Good as the Data Models, Their Related Metadata, and the Tools: For the Module Author 336 Introduction 336 Designing Modules 336 Understanding Your Module’s Impact 349 Interview with the Expert 350 Summary 352 Endnotes 352 9 Automation Is as Good as the Data Models, Their Related Metadata, and the Tools: For the Application Developer 354 Introduction 354 Working with YANG Modules 355 Interacting with the Network 366 Making YANG Language Native 373 Interview with the Expert 380 Summary 381 Endnotes 382 10 Using NETCONF and YANG 384 Introduction 384 So the Story Goes 385 Top-Down Service Model 386 Bottom-Up Device Templates 392 Service Logic Connecting the Dots 394 Setting Up NETCONF on a Device 398 Discovering What’s on a Device 400 Managing Services 405 Manager Synchronization with Devices 413 Network-Wide Transactions 417 Interview with the Experts 425 Summary 428 11 YANG Model Design 430 Introduction 430 Modeling Strategy 430 YANG Modeling Tips 433 Common YANG Mistakes 443 Backward Compatibility 457 Interview with the Experts 460 Summary 462 References in This Chapter 463 9780135180396, TOC, 4/4/19