Part I Voice over IP 3

Chapter 1 Cisco VoIP Implementations 5

“Do I Know This Already?” Quiz 5

Foundation Topics 10

Introduction to VoIP Networks 10

Benefits of Packet Telephony Networks 10

Packet Telephony Components 11

Analog Interfaces 13

Digital Interfaces 14

Stages of a Phone Call 15

Distributed Versus Centralized Call Control 16

Digitizing and Packetizing Voice 19

Basic Voice Encoding: Converting Analog to Digital 19

Basic Voice Encoding: Converting Digital to Analog 20

The Nyquist Theorem 21

Quantization 22

Compression Bandwidth Requirements and Their Comparative Qualities 24

Digital Signal Processors 25

Encapsulating Voice Packets 27

End-to-End Delivery of Voice 27

Protocols Used in Voice Encapsulation 30

Reducing Header Overhead 32

Bandwidth Calculation 34

Impact of Voice Samples and Packet Size on Bandwidth 34

Data Link Overhead 37

Security and Tunneling Overhead 37

Calculating the Total Bandwidth for a VoIP Call 39

Effects of VAD on Bandwidth 41

Implementing VoIP Support in an Enterprise Network 42

Enterprise Voice Implementations 42

Voice Gateway Functions on a Cisco Router 44

Cisco Unified CallManager Functions 45

Enterprise IP Telephony Deployment Models 46

Single-Site Model 46

Multisite with Centralized Call Processing Model 46

Multisite with Distributed Call Processing Model 47

Clustering over WAN Model 48

Identifying Voice Commands in IOS Configurations 48

Call Admission Control (CAC) 49



Part II Quality of Service 55



Chapter 2 IP Quality of Service 57

“Do I Know This Already?” Quiz 57

Foundation Topics 62

Introduction to QoS 62

Converged Network Issues Related to QoS 62

Available Bandwidth 63

End-to-End Delay 64

Delay Variation 65

Packet Loss 66

Definition of QoS and the Three Steps to Implementing It 68

Implementing QoS 69

Identifying and Comparing QoS Models 72

Best-Effort Model 72

Integrated Services Model 73

Differentiated Services Model 74

QoS Implementation Methods 76

Legacy Command-Line Interface (CLI) 76

Modular QoS Command-Line Interface (MQC) 76

AutoQoS 79

Router and Security Device Manager (SDM) QoS Wizard 81

Foundation Summary 89

Q&A 91



Chapter 3 Classification, Marking, and NBAR 93

“Do I Know This Already?” Quiz 93

Foundation Topics 97

Classification and Marking 97

Layer 2 QoS: CoS on 802.1Q/P Ethernet Frame 98

Layer 2 QoS: DE and CLP on Frame Relay and ATM (Cells) 99

Layer 2 1/2 QoS: MPLS EXP Field 100

The DiffServ Model, Differentiated Services Code Point (DSCP), and Per-Hop Behavior

(PHB) 100

IP Precedence and DSCP 102

QoS Service Class 106

Trust Boundaries 108

Network Based Application Recognition (NBAR) 110

Cisco IOS Commands to Configure NBAR 112

Foundation Summary 118

Q&A 119



Chapter 4 Congestion Management and Queuing 123

“Do I Know This Already?” Quiz 123

Foundation Topics 127

Introduction to Congestion Management and Queuing 127

First-In-First-Out, Priority Queuing, Round-Robin, and Weighted Round-Robin Queuing 130

Weighted Fair Queuing 132

WFQ Classification and Scheduling 133

WFQ Insertion and Drop Policy 135

Benefits and Drawbacks of WFQ 135

Configuring and Monitoring WFQ 135

Class-Based Weighted Fair Queuing 138

Classification, Scheduling, and Bandwidth Guarantee 139

Benefits and Drawbacks of CBWFQ 140

Configuring and Monitoring CBWFQ 141

Low-Latency Queuing 142

Benefits of LLQ 144

Configuring and Monitoring LLQ 144

Foundation Summary 146

Q&A 147



Chapter 5 Congestion Avoidance, Policing, Shaping, and Link

Efficiency Mechanisms 149

“Do I Know This Already?” Quiz 149

Foundation Topics 153

Congestion Avoidance 153

Tail Drop and Its Limitations 153

Random Early Detection 154

Weighted Random Early Detection 156

Class-Based Weighted Random Early Detection 158

Configuring CBWRED 158

Traffic Shaping and Policing 163

Measuring Traffic Rates 165

Cisco IOS Policing and Shaping Mechanisms 167

Link Efficiency Mechanisms 167

Layer 2 Payload Compression 168

Header Compression 169

Link Fragmentation and Interleaving 171

Applying Link Efficiency Mechanisms 171

Foundation Summary 172

Q&A 175



Chapter 6 Implementing QoS Pre-Classify and Deploying End-to-End QoS 177

“Do I Know This Already?” Quiz 177

Foundation Topics 180

Implementing QoS Pre-Classify 180

Virtual Private Networks (VPN) 180

QoS Pre-Classify Applications 181

QoS Pre-Classification Deployment Options 183

Deploying End-to-End QoS 185

QoS Service Level Agreements (SLAs) 186

Enterprise Campus QoS Implementations 188

WAN Edge QoS Implementations 190

Control Plane Policing (CoPP) 192

Foundation Summary 194

Q&A 198



Chapter 7 Implementing AutoQoS 201

“Do I Know This Already?” Quiz 201

Foundation Topics 205

Introducing AutoQoS 205

Implementing and Verifying AutoQoS 207

Two-Step Deployment of AutoQoS Enterprise on Routers 209

Deploying AutoQoS VoIP on IOS-Based Catalyst Switches 210

Verifying AutoQoS on Cisco Routers and IOS-Based Catalyst Switches 212

AutoQoS Shortcomings and Remedies 215

Automation with Cisco AutoQoS 215

Common AutoQoS Problems 218

Interpreting and Modifying AutoQoS Configurations 219

Foundation Summary 222

Q&A 227



Part III Wireless LAN 229



Chapter 8 Wireless LAN QoS Implementation 231

“Do I Know This Already?” Quiz 231

Foundation Topics 235

The Need for Wireless LAN QoS 235

WLAN QoS Description 237

Split MAC Architecture and Light Weight Access Point 238

Current Wireless LAN QoS Implementation 239

Configuring Wireless LAN QoS 243

Foundation Summary 247

Q&A 252



Chapter 9 Introducing 802.1x and Configuring Encryption and Authentication

on Lightweight Access Points 255

“Do I Know This Already?” Quiz 255

Foundation Topics 258

Overview of WLAN Security 258

WLAN Security Issues 258

Evolution of WLAN Security Solutions 259

802.1x and EAP Authentication Protocols 260

EAP Authentication Protocols 262

Cisco LEAP 262

EAP-FAST 264

EAP-TLS 266

PEAP 267

WPA, 802.11i, and WPA2 269

Configuring Encryption and Authentication on Lightweight Access Points 272

Open Authentication 272

Static WEP Authentication 273

WPA Preshared Key 274

Web Authentication 276

802.1x Authentication 278

Foundation Summary 281

Q&A 285



Chapter 10 WLAN Management 287

“Do I Know This Already?” Quiz 287

Foundation Topics 291

The Need for WLAN Management 291

Cisco Unified Wireless Networks 291

Cisco WLAN Implementation 292

WLAN Components 294

CiscoWorks Wireless LAN Solution Engine 295

WLSE Software Features 295

WLSE Key Benefits 296

CiscoWorks WLSE and WLSE Express 296

Simplified WLSE Express Setup 297

WLSE Configuration Templates 298

WLSE IDS Features 298

WLSE Summary 298

Cisco Wireless Control System 299

WCS Location Tracking Options 300

WCS Base Software Features 300

WCS Location Software Features 301

WCS Location + 2700 Series Wireless Location Appliance Features 301

WCS System Features 301

Cisco WCS User Interface 302

Cisco WCS System Requirements 302

WCS Summary Pages 303

Wireless Location Appliance 304

Wireless Location Appliance Architecture 305

Wireless Location Appliance Applications 305

WCS Configuration Examples 306

WCS Login Steps 306

Changing the Root Password 306

Adding a Wireless LAN Controller 307

Configuring Access Points 308

WCS Map 309

Adding a Campus Map 309

Adding a New Building 310

Rogue Access Point Detection 312

Rogue Access Point Alarms 312

Rogue Access Point Location 313

Foundation Summary 314

Q&A 317



Part IV Appendix 319



Appendix A Answers to the “Do I Know This Already?” Quizzes and Q&A Sections 321