Fax, Modem, and Text for IP Telephony

This is the eBook version of the printed book. If the print book includes a CD-ROM, this content is not included within the eBook version. IP Telephony has revolutionized many aspects of telecommunications and it continues to be deployed at a rapid pace. The benefits of transporting voice over an IP infrastructure include increased flexibility, better scalability, and a significant cost savings over traditional telephony networks. However, during the deployment of these VoIP solutions, other types of traditional telephony communications that can also realize these same benefits are often overlooked or ignored.   Fax, Modem, and Text for IP Telephony is a comprehensive resource that confronts the need for information on transporting alternative, non-voice communications over the IP protocol. Beginning with the basic theory and operation of fax, modem, and text telephony, this book then educates you on all of the current transport options that are available. An extensive design guide then provides the pertinent advice and best practices for making the correct planning decisions and choosing the best transport option for your network.   Fax, Modem, and Text for IP Telephony also includes meticulous configuration and troubleshooting guides. The configuration guides in this book include a number of sample configurations and tips to manage any fax, modem, or text deployment. The troubleshooting guides present the essential methodologies, debugs, and analysis tools for quickly resolving both the common and complex issues that may be encountered. This book is the perfect companion to other VoIP resources, and it is the only book that empowers you to successfully handle any fax, modem, or text implementation.   David Hanes, CCIE® No. 3491, is currently a senior engineer specializing in training, network design assistance, and troubleshooting of fax technologies for the Customer Assurance Engineering (CAE) group at Cisco®. Since joining Cisco in 1997, David has worked as a TAC engineer for the WAN, WAN Switching, and Multiservice Voice teams, a team lead for the Multiservice Voice team, and an escalation engineer covering a variety of voice and fax technologies. David has troubleshot escalated issues in Cisco customer networks worldwide and remains a technical resource for other Cisco employees and customers.   Gonzalo Salgueiro CCIE No. 4541, is a senior escalation engineer supporting voice, fax, and modem technologies for the Cisco TAC. Gonzalo has spent more than 11 years troubleshooting complex issues in large-scale VoIP networks as well as providing technical leadership for some of the most critical worldwide voice and fax deployments. Prior to joining the Escalation Team in 1999 Gonzalo had roles as a TAC engineer for both the Access/Dial and Multiservice Voice teams as well as a team lead for the Access/Dial team.   Learn basic and advanced operational theory and practical implementation of fax, modem, and text communications Understand how to implement fax, modem, and text communications using protocols such as H.323, SIP, MGCP, and SCCP. Explore the functionality and advantages of T.38 fax relay, passthrough, modem relay, T.37 Store-and-Forward Fax, and text relay for IP network deployments Employ expert-recommended best practices and design solutions for deploying fax, modem, and text in an IP telephony environment Optimize your network with comprehensive fax, modem, and text configuration and design tips for use with IOS and non-IOS gateways Master the latest fax, modem, and text troubleshooting tools and techniques employed by Cisco engineers   Category: Cisco Press–IP Communication Covers: Fax, Modem, and Text Telephony Technologies for Integrated IP Networks   $55.00 USA / $61.00 CAN

Table of Contents:
    Introduction xxiii Part I  Laying the Groundwork 3 Chapter 1  How Modems Work 5     A Brief History of Modems 5     Modem Architecture 8     Modem Types 10         External Versus Internal Modems 10         Hardware Versus Software Modems 10         Fax Modems 12     Terminal-to-Modem Communication 14         DTE and DCE 15         RS-232 Signaling 15         Asynchronous Framing 19         User Interface 20     Modem-to-Modem Communication 26         Modulation 26             Frequency Shift Keying (FSK) 28             Phase Shift Keying (PSK) 29             Amplitude Modulation (AM) 30             Quadrature Amplitude Modulation (QAM) 31             Trellis Coded Modulation (TCM) 32         Modulation Standards 33     Modem Call Analysis 34         Call Setup 35             Phase I: Network Interaction 36             Phase II: Probing/Ranging 38             Phase III: Equalizer and Echo Canceller Training 40             Phase IV: Final Training 41         Data Mode 42             Retrains and Speedshifts 42             Error Control 45             Data Compression 48         Call Disconnect 49     Summary 51 Chapter 2  How Fax Works 53     A Brief History of Fax 54     Fax Components 56     Group Classifications 57     Specifications and Standards 58     Fax Modulations 59     Fax Messaging 61         Phases of a Fax Call 62         Message Format Overview 63         Analyzing a Basic Fax Call 65             CNG Tone 66             CED Tone 67             DIS, NSF, and CSI Messages 68             DCS and TSI Messages 71             TCF, CFR, and FTT Messages 73             MPS, EOP, EOM, MCF, RTP, RTN, and DCN Messages 75             Other T.30 Messages 77         Understanding Error Correction Mode 81             ECM Call Analysis 82             PPS and PPR 84         Important G3 Timers 86         Super G3 Faxing 88             Comparison of SG3 and G3 89             Super G3 Call Analysis 89         Page Encoding 91             Modified Huffman 92             Modified READ 97             Modified Modified READ 103     Summary 105 Chapter 3  How Text Telephony Works 107     A Brief History of Text Telephony 107     Text Telephone Terminology 110     Standards and Specifications 110         Carrier Based Versus Carrierless Protocols 111         ITU-T Recommendation V.18 112     Text Telephone Operation 112         Acoustic Coupling Versus Direct Connections 113         Originating and Receiving Text Telephone Calls 114         Conversation Conventions 116         Text Telephone Relay Services 118         HCO (Hearing Carry Over) 119         VCO (Voice Carry Over) 120     Baudot Protocol 121         Baudot Character Set 121         Baudot Modulation Details 123     Summary 124 Part II  IP Solutions and Design 127 Chapter 4  Passthrough 129     Passthrough Fundamentals 130     NSE-Based Passthrough 137         Fax Passthrough with NSE 139         Modem Passthrough with NSE 141     Protocol-Based Pass-Through for Fax 143         Fax Pass-Through with H.323 Signaling 144         Fax Pass-Through with SIP Signaling 145     Text over G.711 146     A Future Look at ITU-T V.152 147     Summary 148 Chapter 5  Relay 151     Relay Fundamentals 151     Fax Relay 154         T.38 Fax Relay 155             NSE-Based Switchover for T.38 167             Protocol-Based Switchover for T.38 169         Cisco Fax Relay 173     Modem Relay 175     Cisco Text Relay 181     A Future Look at ITU-T T.38, V.150.1, and V.151 185     Summary 185 Chapter 6  T.37 Store-and-Forward Fax 189     Overview of T.37 Store-and-Forward Fax 189     SMTP Overview 191         SMTP Commands and Sample Sessions 192         DSN and MDN 195     T.37 Onramp 201     T.37 Offramp 203     Summary 204 Chapter 7  Design Guide for Fax, Modem, and Text 207     General Passthrough and Relay Design Considerations 208         Bandwidth 209         Call Control Protocol 214         QoS 215         Redundancy 221         Resource Utilization 224         Secure RTP 227         Timing and Synchronization 229     Fax Design Considerations 231         Gateway Interoperability Considerations 231         Error Correction Mode 233         Super G3 235         Hairpin Calls 237         Fallback 239         T.37 Store-and-Forward Fax 241         Fax Detect Script 243         Unified CM Integration 245         Comparing Fax Passthrough and Fax Relay 249     Modem Design Considerations 251         Comparing Modem Passthrough and Cisco Modem Relay 252         Secure Modem Relay 254     Text Design Considerations 256     Summary and Best Practices 258 Chapter 8  Fax Servers 263     Fax Server Basics 264     Fax Server Integration Solutions 269         Fax Server TDM Integration with a Cisco Voice Gateway 269         Fax Server T.38 Integration with a Cisco Voice Gateway 272         Fax Server T.38 Integration with Unified CM 276     Fax Server Redundancy and Failover 281     Summary 283 Part III  Configuration 285 Chapter 9  Configuring Passthrough 287     IOS Gateway Passthrough Configuration 288         IOS Gateway NSE-Based Passthrough Configuration 289         IOS Gateway NSE-Based Passthrough Configuration for H.323, SIP, and SCCP 289             IOS Gateway NSE-Based Passthrough Configuration for MGCP 292         IOS Gateway Protocol-Based Pass-Through Configuration 293         IOS Gateway Text over G.711 Configuration 295     6608 Catalyst Blade Passthrough Configuration 295     VG248 Passthrough Configuration 298     ATA Passthrough Configuration 303     Summary 308 Chapter 10  Configuring Relay 311     IOS Gateway Relay Configuration 311         Fax Relay 312             IOS Gateway Fax Relay Configuration for H.323, SIP, and SCCP 313             IOS Gateway Fax Relay Configuration for MGCP 320         Modem Relay 325             IOS Gateway Cisco Modem Relay Configuration for H.323, SIP, and SCCP 326             IOS Gateway Cisco Modem Relay Configuration for MGCP 329         Cisco Text Relay 332         IOS Example Configurations for Relay 334             Default Fax Relay Configuration for H.323 and SIP 334             Cisco Fax Relay and Modem Passthrough Configuration for H.323 and SIP 336             T.38 Fax Relay, Cisco Modem Relay, and Cisco Text Relay Configuration for H.323‡and‡SIP 337             T.38 Fax Relay and Cisco Text Relay Configuration for SCCP 339             T.38 Fax Relay and Modem Passthrough Configuration for MGCP 340     6608 Catalyst Blade Fax Relay Configuration 342     VG248 Fax Relay Configuration 344     Summary 347 Chapter 11  Configuring T.37 StoreandForward Fax 351     Enabling T.37 Store-and-Forward Fax 351     Loading the TCL Scripts 352     Configuring T.37 Onramp Fax 354         Dial-Peer Configuration for Onramp Fax 355         Fax Receive Configuration Command for Onramp Fax 360         MTA Configuration Commands for Onramp Fax 361         Sample Onramp Configuration 365     Configuring T.37 Offramp Fax 367         Dial-Peer Configuration for Offramp Fax 367         Fax Send Configuration Commands for Offramp Fax 369         MTA Configuration Commands for Offramp Fax 372         Sample Offramp Configuration 373     Summary 375 Part IV  Troubleshooting 377 Chapter 12  Troubleshooting Passthrough and Relay 379     Attacking the Problem 380     Fundamental Troubleshooting 382         Checking the Condition of Originating and Terminating Devices 383         Testing with Voice Calls 384         Testing with PSTN Calls 385         Confirming the Configuration 386         Debugging Best Practices 387     Telephony and IP Troubleshooting 391         Call Legs in IOS Gateways 392         Viewing Call Legs 394             Modem Passthrough Call Legs 394             Fax Pass-Through Call Legs 399             Fax Relay Call Legs 400             Cisco Modem Relay Call Legs 402             Text Telephony Call Legs 404             Call Leg Troubleshooting Techniques 405         Telephony Troubleshooting 407         IP Troubleshooting 414             IP Troubleshooting for IOS Gateways 416             IP Troubleshooting for Non-IOS Gateways 419             IP Troubleshooting Using Packet Captures 424     Troubleshooting the Switchover Signaling 428         Troubleshooting NSE-Based Switchovers 430             NSE-Based Switchover for Modem Passthrough 430             NSE-Based Switchover for Cisco Modem Relay 434             NSE-Based Switchover for T.38 Fax Relay 436             Validating NSE Switchover Support 438         Troubleshooting Protocol-Based Switchovers 445             Protocol-Based Fax Pass-Through and T.38 Switchovers for H.323 446             Protocol-Based Fax Pass-Through and T.38 Switchovers for SIP 451             Protocol-Based T.38 Switchover for MGCP 455             Protocol-Based Switchovers and Unified CM 459         Troubleshooting the Cisco Fax Relay Switchover 461     Passthrough and Relay Troubleshooting 464         Troubleshooting DSP Functions 464             DSP HPI Troubleshooting 465             Loss Planning 478         Advanced Troubleshooting for Passthrough 485         Advanced Troubleshooting for Fax Relay 487             Fax Relay Data Rate 487             Dealing with Packet Loss 488             SG3 490             Debugging T.30 Fax Messaging 491             Analyzing T.38 Fax Relay Packet Captures 497             NSF/NSS 499             Handling High Delay 500         Advanced Troubleshooting for Modem Relay 503             Checking the Modem Endpoints 503             Debugging Modem Relay 505         Advanced Troubleshooting for Cisco Text Relay 506         PCM Traces for Fax and Modem 510             Capturing PCM Traces 511             Analyzing PCM Traces 515     Summary 523 Chapter 13  Troubleshooting T.37 StoreandForward Fax 525     Checking the Basics 525     T.37 Onramp Troubleshooting 527         Troubleshooting the Onramp Telephony Interface 532         Troubleshooting the TIFF Image Creation 537         Troubleshooting the Onramp SMTP Connection 540     T.37 Offramp Troubleshooting 545         Troubleshooting the Offramp SMTP Connection 549         Troubleshooting the Creation of the Fax Page Image 553         Troubleshooting the Offramp Telephony Interface 556     Summary 559 TOC, 1587052695, 5/20/2008  

About the Author :
David Hanes, CCIE No. 3491, currently works as an engineer for the Cisco Customer Assurance Engineering (CAE) group based out of Research Triangle Park, North Carolina supporting various emerging technologies through product testing and field trials. In addition, David is a technical expert for Cisco in the area of fax over IP technologies and assists with network design and troubleshooting for critical fax over IP deployments. Since joining Cisco in 1997, he has worked as a Technical Assistance Center (TAC) engineer for the WAN, WAN Switching, and Multiservice Voice teams, a team lead for the Multiservice Voice team, and an Escalation Engineer covering a variety of voice and fax technologies. David has troubleshot escalated issues in Cisco customer networks worldwide and remains a technical resource for other Cisco employees and customers. Before working at Cisco, David was a Systems Engineer for Sprint, where he gained his first computer networking experience working on the Frame Relay and X.25 protocols. He holds a bachelor of science degree in electrical engineering from North Carolina State University.   Gonzalo Salgueiro, CCIE No. 4541, is a senior engineer for the Unified Communications Infrastructure Escalation team of the Technical Assistance Center (TAC) in Research Triangle Park, North Carolina. In his current role, he is a technical leader for fax and voice over IP technologies working directly with Cisco development engineering, TAC support teams, and product serviceability organization, providing support for various Unified Communications products and technologies. Over the past 12 years at Cisco, he has specialized in troubleshooting complex issues for some of the largest VoIP networks and has provided technical leadership for some of the most critical worldwide voice and fax deployments. Before joining the Escalation team in 1999, Gonzalo had roles as a TAC engineer for both the Access/Dial and Multiservice Voice teams and as a team lead for the Access/Dial team. Gonzalo has developed and delivered all levels of training and documentation on these technologies both internally to Cisco technical teams and externally to Cisco customers worldwide. He holds a bachelor of science degree in physics from Jacksonville University and a master of science degree in physics from the University of Miami.