Understanding and Troubleshooting Cisco Catalyst 9800 Series Wireless Controllers

Simone Arena is a principal technical marketing engineer (TME) within the Cisco Enterprise Networking & Cloud group and is primarily focused on enterprise network architecture and on all things related to wireless and mobility. Simone is based in Italy and is a Cisco veteran, having joined Cisco in 1999. Throughout the years, Simone has covered multiple roles at Cisco, starting as a software engineer working with Catalyst switching platforms, to consulting system engineer in the field, to TME within different teams (Enterprise Solution Engineering, Wireless Business Unit, Enterprise Networking and Cloud, and now Networking Experiences Group). Today Simone is the lead TME architect for Catalyst Wireless, and his time is split between helping customers and partners design the best solution that fits their needs and engineering and product management, trying to evolve and improve the products and solutions. Simone is a Distinguished Speaker at Cisco Live and has spoken at Cisco Live events all over the world for several years. Besides wireless and networking, Simone has two passions: his family, with his two daughters Viola and Anita; and Fiorentina, the best soccer team in the world...no question. In his spare time, Simone enjoys listening to music, especially through his new tube amplifier (simply awesome!). Francisco Sedano Crippa, CCIE No. 14859, joined Cisco in 2006. After some years at TAC supporting voice solutions and as a system engineer working with service providers, he moved to the development side, where he worked on routing, datacenter and, during the past 10 years, as a technical leader on the Wireless Controller development team, focused in serviceability, location services, programmability, and cloud. He’s a Cisco Live speaker and is passionate about DevOps and automation, and he is now working on architecting next-generation cloud-based lab services. When not working, he spends his time building a full-size Boeing 737 simulator in his basement and enjoying his other passion: his daughter, Scarlett, and son, Marco, and his wife, Isabel. Nicolas Darchis, CCIE Wireless No. 25344, joined the Wireless and AAA Cisco TAC team in Belgium in 2007, where his main focus was troubleshooting wireless networks, wireless management tools, and security products. Since 2016, Nicolas has been working as a technical leader for wireless at the same technical assistance center in Brussels; he has shifted a big part of his focus to improving product serviceability of new and upcoming products, as well as new software releases. He is also a major contributor to online documentation of Cisco wireless products and has participated in many of the wireless “Ask the Expert” sessions run by the Cisco support community. Nicolas has been a CCIE Wireless No. 25344 since 2009 and, more recently, he has achieved CWNE No. 208. Sudha Katgeri, CCIE No. 45857, is a technical leader in services for Enterprise Wireless and has been with Cisco since 2006. Besides supporting customer escalations, Sudha collaborates with Customer Experience (CX), Enterprise Networking (ENB) Escalation, Engineering, and Product Management to improve product quality and serviceability in the next-generation Catalyst wireless stack. Sudha has a CCIE in Wireless (#45857) and is an author and contributor to Wireless TAC Innovation Tools like Wireless Config Converter, CLI Analyzer, and several documents on cisco.com.

Introduction xxvii

Chapter 1 Cisco C9800 Series 1

Why Cisco C9800? 2

The Role of the Wireless Controller in a Cloud Era 7

Managing the Cisco C9800 10

Cisco Next-Generation Wireless Stack 22

Summary 23

References 23

Chapter 2 Hardware and Software Architecture of the C9800 25

General CAPWAP Split MAC Architecture 25

The Controller Control Plane Architecture Elasticity 27

Wireless Client State Machine 31

One Dataplane to Rule Them All (or Three at the Maximum) 35

Hardware Overview 38

Summary 42

Chapter 3 C9800 Configuration Model 43

C9800 New Configuration Model 43

Cisco C9800 Series Profile and Tag Considerations 48

Summary 64

References 64

Chapter 4 C9800 Deployment and Installation 65

C9800 Deployment Models 65

Setting Up Your First Catalyst Wireless Network 79

Summary 87

References 87

Chapter 5 Security 89

Network Security Fundamentals 89

Wireless Security Fundamentals 116

Securing the Air 128

Securing Your Access Points 148

Securing Your Wireless Controller 151

Encrypted Traffic Analytics 154

Cisco Umbrella 155

Cisco Secure Development Lifecycle (CSDL) 157

Summary 157

References 157

Chapter 6 Mobility and Client Roaming 159

802.11 Roaming 160

Types of Client Roaming 181

C9800 to AireOS Inter-Release Controller Mobility (IRCM) 191

Summary 192

References 193

Chapter 7 RF Deployment and Guidelines 195

Radio Resources Management (RRM) Concepts and Components 195

Challenging RF Environments 199

Radio Resources Management (RRM) 203

DCA 211

RF Profiles 215

Spectrum Intelligence and CleanAir 219

Advanced RF Features 224

Airtime Fairness (ATF) 228

Dynamic Frequency Selection (DFS) 232

Flexible Radio Assignment (FRA) 235

Wireless Intrusion Prevention System (WIPS) and Rogue Detection 238

Summary 246

References 246

Chapter 8 Multicast and Multicast Domain Name System (mDNS) 247

Wireless Multicast 250

Media Stream Feature 263

mDNS 272

Summary 283

References 283

Chapter 9 Quality of Service (QoS) 285

Wi-Fi Quality of Service (QoS) 286

Wi-Fi (802.11) QoS Fundamentals 287

Implementing Wireless QoS on the C9800 300

Designing and Deploying Catalyst C9800 QoS 304

Best Practices 320

Summary 322

References 322

Chapter 10 C9800 High Availability 323

SSO Redundancy 324

HA Teardown 349

SSO Deployment: Impact on Features 350

N+1 Redundancy 352

N+1 vs. SSO High Availability 357

HA in EWC-AP Deployment 358

HA in EWC-SW Deployment 359

Summary 359

References 360

Chapter 11 Cisco DNA Spaces Integration and IoT 361

Value-Added Wireless Services 361

Connected Mobile Experiences (CMX) 372

Cisco DNA Spaces 372

Specific Service Examples 379

Summary 392

References 392

Chapter 12 Network Programmability 393

What Is Network Programmability? 393

Why Is Network Programmability Needed? 393

Is Network Programmability a New Concept? 396

Orchestration of the Entire Network 396

Configuration Repeatability 396

Idempotency 397

Imperative vs. Declarative Models 397

Infrastructure as Code (IaC) 400

Network Programmability in the C9800 401

Data Models 402

YANG Data Models 403

Encoding Formats 406

Protocols 408

Tools to Examine YANG Models 412

How to Examine Data Using NETCONF and YANG Suite 419

How to Examine Data Using RESTCONF and POSTMAN 421

Python and Network Programmability 429

Summary 436

References 436

Chapter 13 Model-Driven Telemetry 437

What Is Model-Driven Telemetry? 437

How to Enable Model-Driven Telemetry 438

Operational Data and KPIs 441

Polling vs. Subscribing 447

Telemetry Streams 448

How to Identify Subtrees in YANG Models 449

Dial-out vs. Dial-in 450

Tools 460

Summary 467

References 467

Chapter 14 Cisco DNA Center/Assurance Integration 469

Introduction 469

Managing the C9800 with Cisco DNA Center 472

Summary 492

References 492

Chapter 15 Backing Up, Restoring, and Upgrading Your C9800 493

Saving and Restoring the Configuration for Disaster Recovery 493

Running IOS-XE in Install or Bundle Mode 500

Upgrading (and Downgrading) the Controller Safely 501

Summary 506

References 506

Chapter 16 Troubleshooting 507

Control Plane Tracing 509

Embedded Packet Capture (EPC) 525

Packet Tracer 531

Troubleshooting Dashboard 536

Other On-the-Box Tools on the C9800 GUI 540

Offline Tools for the C9800 545

Health and KPI Monitoring 548

Summary 577

References 578

Appendix A Setting Up a Development Environment 579

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