Configuring Cisco Voice Over IP

Jason Sinclair, Syngress

ISBN:1931836647, Edition: 2, 2002-08-10

Price: $69.95

Table of Contents

Foreword xxvii

Introduction xxix

Chapter 1 Introduction to Voice Over IP and Business Justifications 1
Introduction 2
Introduction to Voice Over IP 2
General Overview of Voice Technologies 3
Today's VoIP Possibilities 3
The PBX Reality 4
The VoIP Bandwagon 6
Common VoIP Implementation Services 6
Toll Bypass 6
VoFR 6
VoATM 7
Point-to-Point Links 8
Cisco IP Telephony 8
Cisco IP Telephony Clients 8
IP Softphones 9
Cisco Call Manager 9
Gateways 9
Switches 10
Corporate Multimedia 10
Fax 10
Video 11
The Emerging Carrier and Intercarrier VoIP 11
Wholesale Termination 11
IP Transport 11
Basic Toll-Bypass Designs 13
Tie-Line Replacement 13
Where the Money Is 13
The Merging of Voice and Data Networks 14
What About Data? 14
Convergence 15
The PSTN as a Backup 16
Using Frame Relay for Toll Bypass 17
Where to Use VoFR 18
The Growth Curve of Frame Relay 18
When Does Frame Relay Make More Sense? 19
Using Asynchronous Transfer Mode for Toll Bypass 21
Where to Use It 21
Continuous Bit Rate 24
QoS versus Availability 25
Using Point-to-Point Leased Lines for Toll Bypass 27
Return on Investment 29
Reviewing Current Telephony Costs 29
Designing the New Solution 32
Building the ROI and Payback Period 33
Case Study: PBX Replacement with IP Telephony 34
Advanced Features and Integration Possibilities 37
Replacing the Traditional PBX 37
Call Routing 38
Dial Plan 39
Interactive Voice Response 40
Unified Messaging and the Cisco Unity System 41
TAPI Integration 43
Web Click-to-Talk 44
Transfer, Forward, and Conference Capabilities 45
Call Transfer 45
Call Forward 45
Call Park and Call Pickup 46
Music on Hold 46
Conferencing 46
Web Attendant 46
Call Detail Recording and Data Mining 47
Call Detail Records 47
Tracing and Logging 48
Transcoders 48
Summary 49
Solutions Fast Track 51
Frequently Asked Questions 53

Chapter 2 Traditional Voice Telephony
Principles 57
Introduction 58
Analog Systems 58
Basic Telephone System Operation 59
Analog Network Components 61
Voice Encoding: Standards and Techniques 65
Waveform Encoding 65
Source Encoding 66
Cabling 69
Analog Signaling 73
Analog Signal Composition 73
E&M Signaling 77
Loop and Ground Start 80
Dial-Pulse Signaling 81
Dual-Tone Multifrequency 82
Digital Transmission 85
Time-Division Multiplexing 85
Integrated Services Digital Network Signaling 87
ISDN Reference Points 88
Call Control Signaling 89
Channel Associated Signaling 89
Common Channel Signaling 90
Signaling System 7 90
Signaling Points 91
Signaling Links 92
SS7 Protocol Stack 94
Analog-to-Digital Conversion 97
Modems 98
Factors That Affect V.92 Throughput 100
Summary 102
Solutions Fast Track 103
Frequently Asked Questions 107

Chapter 3 VoIP Signaling and Voice
Transport Protocols 109
Introduction 110
An Overview of IP Networks 111
IP Addressing Overview 114
Address Classes 115
Private Address Space 117
Subnetting and Supernetting Review 118
VoIP Signaling, Addressing, and Routing 122
Signaling Between Routers and PBXs 123
VoIP Signaling 124
Introducing H.323 126
H.323 Components 127
H.323 Terminals (Endpoints) 128
H.323 Gateways 128
H.323 Gatekeepers 129
Multipoint Control Units 130
The H.323 Protocol Stack 131
IP,TCP, and UDP 131
Internet Protocol 131
Transmission Control Protocol 132
User Datagram Protocol 132
H.225 132
H.245 132
Registration, Administration, and Status 133
Real-Time Transport Protocol 133
Codecs 133
H.323 Call Stages 134
H.323 Discovery and Registration 134
Device Discovery and Registration 135
Intrazone Call Placement 135
Interzone Call Placement 136
H.323 Call Setup 137
Logical Channel Setup 139
Media Stream and Media Control Flows 141
Call Termination 142
H.323 Endpoint-to-Endpoint Signaling 143
Session Initiation Protocol 144
Key Benefits of Session Initiation Protocol 145
Session Initiation Protocol Components 146
Session Initiation Protocol Messages 147
Media Gateway Control Protocol 148
MGCP Connections 149
MeGaCo/H.248 150
The Role of QoS in Packet-Switched Voice Networks 152
What Is Quality of Service? 153
Applications for Quality of Service 153
Three Levels of QoS 154
Why QoS Is Essential in VOIP Networks 157
Summary 159
Solutions Fast Track 161
Frequently Asked Questions 165

Chapter 4 An Overview of Cisco's VoIP
Components 167
Introduction 168
Exploring the Types of Voice Ports 168
Foreign Exchange Station Interface 168
Foreign Exchange Office Interface 169
E&M Interface 170
E1/T1 Voice Connectivity 172
Voice Modules and Cards 173
Voice Network Modules 173
Voice Interface Cards 176
VIC-2E/M 176
VIC-2FXS 177
VIC-2FXO 177
VWIC-2MFT-T1 177
Two-Port ISDN BRI Card 178
Four-Port Analog DID/FXS VICs 178
Connecting VNMs and VICs to the Router 179
1700 Series Router Configurations 179
Cisco 1751 Modular Access Router 179
The Cisco 1760 Modular Access Router 184
2600, 3600, and 3700 Series Router
Configurations 187
7200 and 7500 Series Router Configurations 195
MC3810 Router Configurations 197
AS5350 and 5850 Universal Gateway Configuration 197
Cisco Catalyst 4000 and 6000 Series Switches 200
Cisco Catalyst 4200 201
VoIP Terminology 202
ATM 202
Bandwidth Consumption 202
CAC 203
Call Legs 203
Codec 203
Delay 203
Dial Peers 203
Dial Plans 203
Echo 204
Frame Relay 204
Gateways and Gatekeepers 204
H.323 204
Jitter 204
MGCP 204
Number Extension and Digit Translation 205
PSTN 205
POTS 205
Serialization Delay 205
SGCP 205
TDM 205
VAD 206
VoATM 206
VoFR 206
VoIP 206
Summary 207
Solutions Fast Track 207
Frequently Asked Questions 209

Chapter 5 VoIP Configurations 211
Introduction 212
Voice Port Cabling and Configuration 212
Port Numbering on the 1700 Series 213
Port Numbering on the 2600 and 3600 Series 214
Port Numbering on the MC3810 Series 215
Port Numbering on the 7200 Series 216
Port Numbering on the AS5x00 Series 216
LED Status 217
Configuring Voice Ports 219
Configuring FXO or FXS Voice Ports 220
Configuring E&M Ports 222
Configuring DID Ports 224
The Connection Command 225
Voice Port-Tuning Commands 226
Concepts of Delay and Echo 226
Fine-Tuning FXS/FXO Ports 229
Fine-Tuning E&M Ports 231
Configuring Dial Plans and Dial Peers 234
Call Legs: POTS versus Voice Network Dial Peers 236
Creating and Implementing Dial Plans 237
Configuring Dial Peers 239
Number Expansion 246
Direct Inward Dialing 246
Configuring Trunking 249
Trunks 249
Tie Lines 251
PLAR 251
PLAR-OPX 252
Direct Voice Trunking versus Dial-Digit
Interpretation 252
Standard Dialing Analysis:Digit Interpretation 253
Supervisory Disconnect 253
Wink-Start Signaling versus Immediate-Start Signaling 255
Configuring ISDN for Voice 257
Configuring ISDN BRI Voice Ports 258
Configuring ISDN PRI Voice Ports 260
Configuring Q.931 Support 263
Configuring QSIG 264
Configuring CAS 264
Configuring CCS 265
Configuring T-CCS 266
Configuring Gateways and Gatekeepers 268
Configuring H.323 Gateway 268
Configuring H.323 Gatekeeper 269
H.323 ID Addresses 270
Zone Prefixes 270
Technology Prefixes 271
Summary 275
Solutions Fast Track 276
Frequently Asked Questions 279

Chapter 6 Configuring QoS for VoIP 281
Introduction 282
QoS Overview 282
Available QoS Options 283
Maximizing Bandwidth 284
Compressed Real-Time Transport Protocol 285
Understanding Real-Time Transport Protocol 285
RTP Header Compression 285
cRTP Implementation 287
Queuing 287
Custom Queuing 288
Priority Queuing 288
Weighted Fair Queuing 289
CBWFQ 291
Priority Queuing with WFQ 292
Packet Classification 292
IP Precedence 293
Policy Routing 294
Resource Reservation Protocol 294
Call Admission Control 295
RTP Priority 297
Traffic Shaping 298
Weighted Random Early Detection 298
Link Fragmentation and Interleaving 299
VoIP QoS Configuration Examples 300
Maximizing Bandwidth 300
Configuring cRTP 301
Enable cRTP on a Serial Interface 301
Enable cRTP with Frame Relay
Encapsulation 301
Change the Number of Header Compression Connections 302
Displaying Statistics 302
CRTP Configuration Examples 302
Configuring Queuing 303
Configuring Custom Queuing 304
Enabling Custom Queuing 304
Adjusting Byte Counts and Queue Sizes 305
Applying Your Configuration to an Interface 306
Verifying Custom Queuing 306
Configuring Priority Queuing 308
Enabling Priority Queuing 308
Configuring the Queue Limits 309
Applying Your Priority List to an Interface 310
Verifying Priority Queuing 311
Configuring Weighted Fair Queuing 312
Enabling Weighted Fair Queuing 312
Verifying Weighted Fair Queuing 313
Configuring Class-Based Weighted Fair Queuing 314
Defining Class Maps 315
Creating Policies 316
Attaching Policies to Interfaces 318
Verifying CBWFQ 319
Configuring Packet Classification 320
IP Precedence 321
Verifying IP Precedence 321
Policy Routing 322
Verifying Policy Routing 322
Configuring RSVP 323
Verifying RSVP 323
Call Admission Control 325
Verifying Call Admission Control 326
Configuring Priority Queuing with WFQ (IP RTP Priority) 329
Verifying Priority Queuing with WFQ 330
Configuring Traffic Shaping 331
Verifying Traffic Shaping 333
Configuring Congestion Avoidance with WRED 333
Verifying WRED 334
Configuring Link Fragmentation and Interleaving 335
Verifying Link Fragmentation and Interleaving 336
Summary 338
Solutions Fast Track 339
Frequently Asked Questions 340

Chapter 7 Testing and Troubleshooting VoIP 343
Introduction 344
A Basic Troubleshooting Methodology 345
Layer 1 Troubleshooting 346
Troubleshooting Equipment, from Powerup to Operating State 346
Troubleshooting Cabling 348
Troubleshooting Ports 351
Troubleshooting Other Physical Layer Issues 353
Troubleshooting Private Branch Exchange Problems 354
Troubleshooting Central Office Problems 355
Troubleshooting Underlying Circuit and Network Problems 356
Layer 2 Troubleshooting 365
Troubleshooting Serial Interfaces 365
Troubleshooting Frame Relay 367
Troubleshooting Asynchronous Transfer Mode 372
Layer 3 Troubleshooting 375
Troubleshooting IP 376
IP Addressing and Routing 376
IP Quality of Service 377
Queuing 379
Bandwidth Reservation Schemes 381
Resource Reservation Protocol 383
Troubleshooting Dial Plans 384
Troubleshooting Voice Ports 388
Troubleshooting FXS and FXO Voice Ports 388
Troubleshooting E&M Voice Ports 392
Troubleshooting Dial Peers 395
Troubleshooting Signaling Errors 399
FXS/FXO signaling 399
Loop Start 399
Ground Start 400
E&M Signaling 401
Wiring Schemes 401
Trunk Seizure 402
Troubleshooting Gateways and Gatekeepers 405
Summary 408
Solutions Fast Track 410
Frequently Asked Questions 413

Chapter 8 Connecting PABXs with VoIP Scenarios 415
Introduction 416
Collecting the Information 416
Gathering Information for Design Purposes 417
Compiling the Information 420
VoIP Corporation's Tie-Line Replacement 421
Business Drivers 421
Key Stakeholders 422
Hardware 422
Software 423
Documentation 423
Security 423
Compiling the Information 423
Business Case:VoIP Tie-Line Replacement 424
Designing a Basic Tie-Line Replacement
with VoIP 429
Basic Design Principles for Tie-Line Replacement 429
Designing the Basic Tie-Line Replacement 432
Configuring a Basic Tie-Line Replacement with VoIP 435
Configuration Details for the Basic Tie-Line Replacement 436
Atlanta Router 436
New York Router 436
Chicago Router 436
Atlanta Router 437
Atlanta Router 437
Atlanta Router 438
Chicago Router 438
Atlanta Router Configuration 439
Chicago Router Configuration 442
New York Router Configuration 443
Configuring Advanced Trunking Scenarios 446
Advanced Trunking Options Overview 446
Configuring Advanced Trunking Options:Case Studies 447
Atlanta Router Configuration 447
Chicago Router Configuration 448
Atlanta Router Configuration 449
New York Router Configuration 450
Integrating Voice and Data 451
The Rationale for Integrating Voice and Data Networks 451
Integrating Voice and Data: Case Studies 451
Atlanta Router Configuration 453
Atlanta Router Configuration 456
Chicago Router Configuration 459
New York Router Configuration 461
Verifying and Testing the Solution 463
Testing and Verification Methodology 463
Testing the Deployed Solutions 464
Testing Tie-Line Replacement 464
Testing Advanced Trunking 466
Testing Voice and Data Integration 467
Summary 468
Solutions Fast Track 468
Frequently Asked Questions 471 Chapter 9 Intra- and Interoffice VoIP Scenarios 473
Introduction 474
Creating a Basic Intraoffice Dial Plan 474
What Is a Dial Plan? 474
Collecting the Information 475
Scenario 1 476
Determining the Requirements 476
Designing the Dial Plan 477
Designing a Single-Router VoIP Network 478
Choosing the Hardware 478
Creating the Design Plan 479
Configuring a Single-Router VoIP Network 480
Reviewing the Design 480
Configuring the Router: Step by Step 482
Testing and Verification 485
Merging the PBX and VoIP Networks 486
Designing PBX Interconnect Trunks 486
Scenario 2 486
Configuring the Router 488
Testing and Verification 492
Configuring a Multirouter Intraoffice VoIP Network 494
Extending the Dial Plan 494
Extending the Design 495
Configuring the Routers 496
Testing and Verification 499
Router1 500
Router2 501
Configuring VoIP for Interoffice Voice Communication 503
Extending the Dial Plan Again 503
Extending the Design 504
Configuring the Routers 505
Tuning the VoIP Network 511
Tuning the Design 511
Testing and Verification 513
Router1 513
Router2 516
Router3 518
Applying QoS to the VoIP Network 520
Designing the QoS Solution 520
Configuring the Routers for QoS 521
Testing and Verification 521
Summary 523
Solutions Fast Track 524
Frequently Asked Questions 526

Index 529