Deploying and Troubleshooting Cisco Wireless LAN Controllers
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Deploying and Troubleshooting Cisco Wireless LAN Controllers

3.5 2
by Mark L. Gress, Lee Johnson

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ISBN-10: 1587058146

ISBN-13: 9781587058141

Pub. Date: 11/30/2009

Publisher: Cisco Press

This is the only complete, all-in-one guide to deploying, running, and troubleshooting wireless networks with Cisco® Wireless LAN Controllers (WLCs) and Lightweight Access Point Protocol (LWAPP)/Control and Provisioning of Wireless Access Points (CAPWAP). Authored by two of the most experienced Cisco wireless support professionals, the book


This is the only complete, all-in-one guide to deploying, running, and troubleshooting wireless networks with Cisco® Wireless LAN Controllers (WLCs) and Lightweight Access Point Protocol (LWAPP)/Control and Provisioning of Wireless Access Points (CAPWAP). Authored by two of the most experienced Cisco wireless support professionals, the book presents start-to-finish coverage of implementing WLCs in existing wired and wireless network environments, troubleshooting design-related issues, and using LWAPP/CAPWAP solutions to achieve your specific business and technical goals.

One step at a time, you’ll walk through designing, configuring, maintaining, and scaling wireless networks using Cisco Unified Wireless technologies. The authors show how to use LWAPP/CAPWAP to control multiple Wi-Fi wireless access points at once, streamlining network administration and monitoring and maximizing scalability. Drawing on their extensive problem-resolution experience, the authors also provide expert guidelines for troubleshooting, including an end-to-end problem-solving model available in no other book.

Although not specifically designed to help you pass the CCIE® Wireless written and lab exams, this book does provide you with real-world configuration and troubleshooting examples. Understanding the basic configuration practices, how the products are designed to function, the feature sets, and what to look for while troubleshooting these features will be invaluable to anyone wanting to pass the CCIE Wireless exams.

  • Efficiently install, configure, and troubleshoot Cisco Wireless LAN Controllers
  • Move autonomous wireless network solutions to LWAPP/CAPWAP
  • Integrate LWAPP/CAPWAP solutions into existing wired networks
  • Understand the next-generation WLC architecture
  • Use Hybrid REAP and Home AP solutions to centrally configure and control branch/remote access points without deploying controllers in every location
  • Use Mobility Groups to provide system-wide mobility easily and cost-effectively
  • Use Cisco WLC troubleshooting tools, and resolve client-related problems
  • Maximize quality in wireless voice applications
  • Build efficient wireless mesh networks
  • Use RRM to manage RF in real-time, optimizing efficiency and performance
  • Reference the comprehensive WLC and AP debugging guide

Part of the CCIE Professional Development Series, this is the first book to offer authoritative training for the new CCIE Wireless Exam. It will also serve as excellent preparation for Cisco’s new CCNP® Wireless exam.

Product Details

Cisco Press
Publication date:
CCIE Professional Development Series
Product dimensions:
7.50(w) x 9.20(h) x 1.40(d)

Table of Contents

Introduction xviii

Chapter 1 Troubleshooting Strategy and Implementation 1

Developing a Troubleshooting Strategy 1

Production Versus Nonproduction Outages 1

Step 1: Gathering Data About the Problem 2

Step 2: Identifying the Problem 2

Step 3: Isolating the Problem 3

Step 4: Analyzing the Data Collected About the Problem 7

Summary 9

Chapter 2 Wireless LAN Controllers and Access Points 11

Wireless LAN Controller Platforms 11

Current Production WLCs 12

Previous WLCMs 15

Functionality Differences Between WLCs 17

WLC Hardware and Software Requirements 19

Lightweight AP Models 20

Cisco Aironet APs 20

Airespace APs 25

AP 1000 Series Functionality Differences 26

AP 1000 Series Limitations 26

Lightweight Compared to Traditional Autonomous APs 28

Scalability 28

RRM 29

Self-Healing Mechanism 30

WLC Features 30

Central Management 32

Summary 35

Chapter 3 Introduction to LWAPP 37

Defining LWAPP 37

Quick Protocol Overview 38

LWAPP Advantages 41

Management 42

Scalability 42

Security 43

Mobility 43

LWAPP Mechanics 44

Discovery Process 45

Join Process 55

Image Process 56

Config State 56

Run State 57

Dissecting the Discovery Response 58

Manually Dissecting the Discovery Response 59

Summary 61

Chapter 4 The CAPWAP Protocol 63

Overview of CAPWAP 64

Differences from LWAPP 65

CAPWAP Session Establishment/AP Joining Process 67

Discovery Process 70

DTLS Session Establishment 71

Join/Config/Run 81

Troubleshooting CAPWAP Session Establishment/AP Discovery and Join 90

CAPWAP Communication: Control and Data Encryption 98

CAPWAP Communication: Sequence Numbers and Retransmissions 100

CAPWAP Fragmentation and Path MTU Discovery 101

CAPWAP-Control Packets Fragmentation 101

CAPWAP-Data Packets Fragmentation 101


802.11 Bindings and Payloads 103

CAPWAP-Data Binding and Payloads 103

CAPWAP-Control Binding and Payloads 104

LWAPP and CAPWAP Vendor-Specific Payloads 105

Summary 105

Chapter 5 Network Design Considerations 107

Controller Placement 107

Access Layer Deployments 108

Distribution Layer Deployments 109

Service Block Deployments 109

WAN Considerations 110

AP Placement 110

Dense AP Deployment Considerations 112

802.11n 114

Location Design Considerations 116

Summary 119

Chapter 6 Understanding the Troubleshooting Tools 121

Troubleshooting on the WLC 121

Debugging 121

Advanced Debugging 126

mping and eping 131

Message Log 132

Trap Log 133

Statistics 135

Controller Statistics 135

AP Statistics 135

RADIUS Server Statistics 137

Port Statistics 137

Mobility Statistics 138

Packet Captures 139

WLC Config Analyzer 140

Software Bug Toolkit 141

Summary 142

Chapter 7 Deploying and Configuring the Wireless LAN Controller 143

Connecting the WLC to the Switch 144

Multiple AP-Manager Support 145

LAG 148

Layer 2 and Layer 3 LWAPP Transport Modes of Operation 151

LWAPP Layer 3 Transport Mode 153

Interfaces on the WLC 156

DHCP Proxy Vs. DHCP Bridging 159

DHCP Proxy Mode 160

DHCP Bridging Mode 163

Overview and Configuration 163

Configure the Switch for the WLC 169

Troubleshooting WLC Issues 171

Summary 176

Chapter 8 Access Point Registration 177

AP Discovery and Join Process 177

Troubleshooting Network Connectivity and AP Registration 181

Verifying VLAN Configuration 181

Verifying IP Addressing Information 182

Understanding the AP Discovery and AP Join Process 183

Troubleshooting the AP Discovery and AP Join Process 191

WLC Config Analyzer 197

AP Debugs 198

Debug Template 198

Summary 199

Chapter 9 Mobility 201

Client Roaming/Mobility Events 202

Intra-Controller Roaming 202

Inter-Controller Roaming 202

Inter-Subnet Roaming/Layer 3 Mobility Events 202

Auto-Anchor Mobility 206

AP Groups 207

Troubleshooting AP Groups 208

Mobility Groups 210

Mobility Messaging 212

Mobility Message Types 212

Mobility Role of the Controller to the Client 213

Mobility Handoff Types 214

Mobility Packet Format 221

Error Recovery 223

Mobility Messaging Enhancements in 5.0 224

Configuring Mobility Groups 224

Configuring Auto-Anchoring 226

Determining Controllers to Add to a Mobility Group 228

Secure Mobility 228

Troubleshooting Mobility 229

PMKID Caching 238

AP Mobility 241

Primary, Secondary, and Tertiary Controllers 241

AP Load Balancing 243

AP Failover 244

Troubleshooting AP Mobility 245

Summary 247

Chapter 10 Troubleshooting Client-Related Issues 249

General Client Information 249

Client Association Packet Flow 250

Client Utilities and Logging 255

AP Debugs and Show Commands 258

Wireless and Wired Sniffer Traces 261

Debug Client 262

Debug Client Variations 263

Client Connection 265

Controller Processes 265

PEM 266

APF 268

802.1x Authentication (Dot1x) 270

Debug Client Analysis 270

Troubleshooting Examples 285

Wrong Client Cipher Configuration 285

Wrong Preshared Key 287

Incorrect User Credentials with EAP 289

Summary 291

Chapter 11 Wireless Voice 293

Prerequisites for Voice Deployments 293

Phone Features 295

Supported Protocols, Specifications, and Certifications 295

Security 296

Coexistence 297

QoS 297

Latency, Jitter, and Loss 298

Correct Packet Marking 298

Upstream and Downstream QoS 302

Wi-Fi Multimedia 303


Configuration 305

Controller 305

Switch Ports 311

WLAN Profile on the Phone 312

Troubleshooting 792x Voice Quality Issues 313

Basic Troubleshooting/Connectivity 313

Choppy/Lost Audio 316

One-Way Voice 319

Network Busy 321

Poor Audio When Roaming 323

Multicast Applications Fail 324

Enabling Trace Logs on the 792x 329

Troubleshooting and Monitoring Tools 337

WCS 338

Packet Capture Software 340

Spectrum Analysis Tools 341

SpectraLink and Vocera Deployments 342

SpectraLink 342

Vocera Deployments 344

Summary 347

Chapter 12 Radio Resource Management 349

How RRM Works 349

RF Grouping 351

Dynamic Channel Assignment 357

TPC 358

Coverage Hole Detection 359

Enhancements to RRM 360

Configuring RRM 362

Dynamic Channel Assignment 363

Transmit Power Control (TPC) 365

Coverage 367

Profiles and Monitor Intervals 368

Overriding Global RRM 369

Troubleshooting RRM 371

SNMP Traps 371

show Commands 373

Debugs 378

Summary 389

Chapter 13 H-REAP 391

H-REAP Versus REAP 392

Split MAC Versus Local MAC Architecture 392

H-REAP Modes of Operation 394

Central Versus Local Switching 395

H-REAP States of Operation 397

H-REAP Wireless Security Support 398

Configuring H-REAP 398

Controller Discovery 398

Configuring the WLAN 402

Configuring the AP 404

Configuring the Local Switch 405

H-REAP Guidelines and Limitations 408

H-REAP Enhancements 410

Backup RADIUS Server 410

H-REAP Groups 411

Local Authentication 412

Troubleshooting H-REAP 412

show Commands 414

debug Commands 422

Summary 430

Chapter 14 Guest Networking 431

Web Authentication 431

Web Authentication Policies 432

Web Authentication Types 435

Web Authentication Process 436

Troubleshooting Basic Web Authentication 440

RADIUS and LDAP Authentication with Web Auth 447

Guest User Accounts 451

Custom Web Auth Splash Pages 452

Global Override 453

Browser Security Warning 454

Centralized Traffic Flow with Guest Access 458

Auto-Anchor/Guest Tunneling 458

Configuring Auto-Anchor 460

Troubleshooting Guest Tunneling 461

Wired Guest Access 467

Troubleshooting Wired Guest Access 470

Summary 471

Chapter 15 Mesh 473

Mesh Code Releases 474

Mesh Deployments 474

How Mesh Works 476

Mesh Bootup and Join Process 477

Configuring Mesh 480

Ethernet Bridging 483

Troubleshooting Mesh 488

AP Join Problems 488

RF Issues 491

show Commands 492

Remote Telnet and AP Debugs 495

Ethernet Bridging Troubleshooting 497

Summary 502

Appendix A Debugging Commands 503

WLC Debugs 503

Existing Debugs in Software Version 5.0 and Earlier 503

Debugs Introduced in Software Version 5.1 518

Debugs Introduced in Software Version 6.0 520

Debug Packet Logging 523

AP Debugs 526

Appendix B LWAPP and CAPWAP Payloads 535

LWAPP and CAPWAP Message Payloads 544

TOC, 9781587058141, 10/19/09

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Deploying and Troubleshooting Cisco Wireless LAN Controllers 3.5 out of 5 based on 0 ratings. 2 reviews.
Anonymous More than 1 year ago
Boudville More than 1 year ago
The first chapter is the most valuable. It offers broad tips for a top down debugging approach to a wireless network problem. Also, it is largely independent of specific hardware elements. You can apply the guidelines even if you have non-Cisco items in the network. Of its advice, two very good tips stand out. The first is simply to have an extensive and complete network diagram. Do this when everything is [presumably] working. Don't wait till things go wrong before amassing such a diagram. The second tip is to imagine you are offsite and are talking on the phone to an onsite sysadmin. And no visuals on your phone. It's strictly audio. This gedanken forces you to focus on what might be the key features of the problem. The rest of the book then delves into specific abilities of Cisco boxes. Often there might be diagnostic text output that you can get. Cisco has been careful about enabling its machines to provide copious diagnostic dumps. The mass of detail is needed because of the many possible failure symptoms. But this also means that part of the skill you should cultivate is an intuition about what to look for in a potential surfeit of a data dump. One impression from the book is that wireless problems can be harder than those in an all-wired network. For the latter, at least in principle, you can trace the wires and test each link. But wireless transceivers can overlap in broadcast range. While evesdropping does not require physical access to your equipment by an adversary.