Product Description

Cisco Voice Gateways and Gatekeepers provides detailed solutions to real-world problems encountered when implementing a VoIP network. Each chapter presents an overview of a technology followed by a detailed scenario and associated solutions. Emphasis is placed on the accepted best practices and common issues encountered. It will initially serve readers as a reference for complex gateway and gatekeeper deployments and will also be a valuable study aid for the Cisco Certifified Voice Professional (CCVP) certification track. Cisco Voice Gateways and Gatekeepers is divided into five sections. Part one provides an introduction to the roles of both gateways and gatekeepers and includes advice on when to use each. Part two focuses on deploying gateways; working with MGCP, H.323, and SIP; connecting to the PSTN, PBXs, and the IP WAN; configuring basic and advanced dial peers; and implementing SRST. Part Three focuses on deploying and configuring gatekeepers. Part four discusses use of gateways and gatekeepers in a service provider environment. Part five addresses use of the Cisco Tool Command Language (TCL). This book is also recommended self-study training for the CCVP GWGK exam.

Product Details

• Amazon Sales Rank: #134479 in Books
• Published on: 2006-08-27
• Original language: English
• Number of items: 1
• Binding: Hardcover
• 648 pages

From the Back Cover

Cisco Voice Gateways and Gatekeepers

Understanding and configuring GW/GK in complex VoIP networks

Denise Donohue, CCIE® No. 9566

David Mallory, CCIE No. 1933

Ken Salhoff, CCIE No. 4915

Deployments of voice over IP (VoIP) networks continue at a rapid pace. Voice gateways are an essential part of VoIP networks, handling the many tasks involved in translating between transmission formats and protocols and acting as the interface between an IP telephony network and the PSTN or PBX. Gatekeepers and IP-to-IP gateways help these networks scale. Gatekeepers provide call admission control, call routing, address resolution, and bandwidth management between H.323 endpoints including Cisco IOS® voice gateways and Cisco® Unified CallManager clusters. IP-to-IP gateways allow VoIP calls to traverse disparate IP networks.

Cisco Voice Gateways and Gatekeepers provides detailed solutions to real-world problems encountered when implementing a VoIP network. This practical guide helps you understand Cisco gateways and gatekeepers and configure them properly. Gateway selection, design issues, feature configuration, and security and high-availability issues are all covered in depth. The abundant examples, screen shots, configuration snips, and case studies make this a truly practical and useful guide for anyone interested in the proper implementation of gateways and gatekeepers in a VoIP network. Emphasis is placed on the accepted best practices and common issues encountered in real-world deployments.

Cisco Voice Gateways and Gatekeepers is divided into four parts. Part I provides an overview of an IP voice network. Part II is dedicated to voice gateways, including discussions of Media Gateway Control Protocol (MGCP); H.323; Session Initiation Protocol (SIP); voice circuit options; connecting to the PSTN, PBX, and IP WAN; dial plans; digit manipulation; route selection; class of restriction; Survivable Remote Site Telephony (SRST) and MGCP fallback; digital signal processor (DSP) resources; and Tool Command Languaue (Tcl) scripts and Voice XML (VXML). Part III addresses voice gatekeepers, including detailed deployment and configuration. Part IV is dedicated to IP-to-IP gateways.

“With this book, the authors provide an in-depth look at the breadth of voice gateway features and capabilities, as well as providing voice gateway configuration guidance.”

–Christina Hattingh, Access Technology Group, Cisco Systems®

• Understand the pros and cons of MGCP, H.323, and SIP, how they implement call signaling and describe call flow, and how to configure each protocol
• Learn the various analog and digital voice circuit options used to connect a VoIP network to the PSTN
• Configure and troubleshoot PSTN, PBX, and IP WAN connections
• Build scalable dial plans and understand the different types of dial peers
• Understand the various ways gateways control called and calling phone numbers
• Examine call admission control (CAC) techniques
• Configure Class of Restrictions (CoR) for both inbound and outbound calls
• Deploy and troubleshoot SRST and MGCP fallback
• Evaluate DSP considerations and resources
• Support interactive voice response (IVR) and advanced call-handing applications using Tcl scripts and VXML
• Deploy and configure basic and advanced gatekeeper functions
• Configure and troubleshoot IP-to-IP gateways

This book is also recommended self-study training for the CCVP GWGK exam.

This IP communications book is part of the Cisco Press® Networking Technology Series. IP communications titles from Cisco Press help networking professionals understand voice and IP telephony technologies, plan and design converged networks, and implement network solutions for increased productivity.

Category: Cisco Press–IP Communications

Covers: VoIP gateways and gatekeepers

$65.00 USA / $81.00 CAN

About the Author

Denise Donohue, CCIE No. 9566, is a design engineer with AT&T. She is responsible for designing and implementing data and VoIP networks for SBC and AT&T customers. Prior to that, she was a Cisco instructor and course director for Global Knowledge. Her CCIE is in Routing and Switching.

David L. Mallory, CCIE No. 1933, is a technical education consultant with Cisco Systems, Inc. supporting Cisco voice certifications. Prior to this role, David was a systems engineer supporting several global enterprise customers. David has presented on voice gateways and gatekeepers at Networkers and has achieved four CCIE certifications: Routing and Switching, WAN Switching, Security, and Voice.

Ken Salhoff,CCIE No. 4915, is a systems engineer with Cisco Systems, Inc. Ken has been specializing in voice technologies with Cisco for the past six years. In the systems engineering role, Ken has supported several global enterprise customers using Cisco voice technologies. Ken has achieved two CCIE certifications: Routing and Switching, and Voice.

Excerpt. © Reprinted by permission. All rights reserved.

Foreword

Cisco IOS routers have shipped with voice interface cards since 1997, and after this capability was available the term voice gateway became part of the VoIP vernacular, seemingly overnight. The voice interfaces allowed routers to provide a critical interconnectivity link between the traditional data IP networks and the traditional voice (PSTN, PBXs, and key systems) networks. With this technology, the industry widely built toll bypass networks during the late 1990s: Enterprises connected their PBXs at different sites with VoIP "trunks" instead of with TIE lines or the PSTN, and service providers leveraged IP backbone networks to offer calling-card services and cut-rate long-distance and international calling.

VoIP did not fascinate the popular imagination of the likes of Jeff Pulver of Voice-on-the Net (VON) and other industry observers until end-user–visible devices, such as IP phones, and IP-based applications brought the technology to the forefront. Voice gateway technology is still the pale sibling of the IP telephony world that creates no buzz, and yet it is also the workhorse of every single VoIP network. Even as VoIP endpoints become ever more prevalent in businesses and residences, voice gateways still provide critical interconnectivity with billions of traditional PSTN and PBX voice endpoints, without which companies cannot operate their communications networks.

Although the idea of a voice gateway is conceptually simple enough—it’s a demarcation between two networks and translates the protocols from one (the TDM world) to the other (the IP world)—the technology has become increasingly sophisticated and the features more intertwined over the years. Choosing the "right" voice gateway and configuring the "right" set of features for a particular network is no longer the task for the uninitiated. The question I hear most frequently is whether to deploy MGCP, H.323, or SIP gateways. Cisco gateways are protocol agnostic and support all of these protocols and several variations thereof, and the answer to the question posed is not a simple one: The optimal network design depends on a large number of considerations. Some protocols and designs are better suited to particular types of networks, partly owing to the architecture of the protocols themselves and partly due to the features that have been chosen for implementation over the years.

A Cisco Press book with comprehensive coverage focused entirely on voice gateway technology and features was a long time coming, and at last with this book, the authors provide an in-depth look at the breadth of voice gateway features and capabilities, as well as providing voice gateway configuration guidance. The book explains the major VoIP protocols, MGCP, H.323, and SIP, their structure and operation, and the considerations to choose among them. It discusses in detail the PSTN and PBX circuit connection technologies and choices. There are often multiple connection choices on the central office or PBX switch as well as on the voice gateway side of the circuit, and which of these would provide the features, cost points, and manageability that are optimal for your network might not be obvious at first glance.

The book goes on to provide insights into many other areas of gateway selection and deployment, including the myriad choices in carrying fax and modem traffic over IP, dial plan features and digit manipulation tools, call admission control capabilities to keep voice traffic off the IP network when it does not have the quality levels to carry it, a review of DSP technology and operation, and an examination of IP connectivity implications and QoS features required to carry voice traffic with decent quality. Later chapters in the book also include discussions on pure IP-oriented topics such as TCL and VXML applications capabilities, conference mixing, transcoding, gatekeeper functions and connectivity, and IP-to-IP gateway (session border controller) services and features. All of these pure VoIP services are offered by the same platforms that are also voice gateways, even though TDM connectivity is not a necessary component for the IP-only services.

The book also covers key areas of interest in any network, including security measures and high availability. VoIP network security is a wide topic fully deserving of its own book-length treatment, but this book provides enough basic information to get your network deployed. It covers how voice gateway traffic passes through firewalls and NAT devices, how to encrypt voice signaling and media traffic to or from a voice gateway, as well as configuring class of service restrictions such that certain call patterns are allowed while others are blocked per the policy of your network. High availability is essential in all networks—a chapter in this book is dedicated to the discussion of how gateways fail over when other network components are out of contact, as well as how gateway features interoperate with IP Phone failover features such as SRST to maintain dial tone and PSTN network access for your end users at all times.

Throughout the book is a case study that solidifies the chapter discussions by providing practical, hands-on examples of how the configuration of the system implements the features. This, together with the detailed chapter-by-chapter coverage of crucial gateway topics, make this an invaluable book essential to the tool chest of anyone contemplating the implementation of a new network, actively designing a network, or evolving or optimizing the features in an existing network.

Christina Hattingh
Access Technology Group
Cisco Systems, Inc.

Customer Reviews

One of a kind book on Cisco Voice Technology
This book is a great practical guide to help people both understand Cisco gateways and gatekeepers and configure them properly. This book describes the Cisco voice gateway and gatekeeper theories and protocols in a way that readers can apply to their own networks. It provides examples, screen shots, configuration snips, and case studies in abundance. The book also includes the typical tasks and issues in deploying voice gateways and gatekeepers, in addition to advanced features and capabilities. Emphasis is placed on the accepted best practices and common issues encountered. It is not written specifically as a preparation for the Cisco Gateway Gatekeeper exam, but the topics that are covered on the exam are included in this book.

The target audience for this book includes network engineers, IP Telephony engineers, and Telco engineers who are tasked with the installation, configuration, and maintenance of VoIP and IP Telephony networks. This book also serves as a resource to CCVP and CCIE voice candidates who are preparing for the written or lab exams. It is assumed that the reader understands IP networking and is familiar with the topics covered in the Cisco courses on CVoice, CIPT, QoS, and IPTT. This includes a basic understanding of VoIP and time-division multiplexing (TDM) voice fundamentals, the concepts and configuration of basic IP voice routers, and Cisco CallManager basics. I describe this book further in the context of its table of contents.

Part I, "Voice Gateways and Gatekeepers"
Chapter 1, "Gateways and Gatekeepers"-- This chapter provides an overview of components of an IP voice network, including different types of gateways, such as routers, standalone devices, and switch modules, H.323 gatekeepers, and IP-to-IP gateways (IPIPGW). It contains a review of the Multiple Gateway Control Protocol (MGCP), H.323, Session Initiation Protocol (SIP), Skinny Client Control Protocol (SCCP), and Real-Time Transport Protocol (RTP) protocols. It also describes different types of call agents that are used in IP voice networks. In addition, it introduces the network used throughout the book in examples and case studies.

Part II, "Gateways"
Chapter 2, "Media Gateway Control Protocol"-- This chapter covers how MGCP implements call signaling, describes call flow using MGCP, and discusses the pros and cons of the protocol and when to use it. It then covers implementing MGCP gateways--configuration of the router, addition of an MGCP gateway to CallManager, configuration of dual tone multifrequency (DTMF) relay, some security features, and troubleshooting of MGCP gateways.

Chapter 3, "H.323"-- This chapter discusses the implemention of call signaling with the H.323 protocol, some of the protocols that are part of the H.323 suite, call flow using H.323, and the pros and cons of the protocol and when to use it. It then covers implementing H.323 gateways--configuring the router, using toll bypass, adding a gateway to CallManager, configuring DTMF relay, allowing H.323-to-H.323 connections, configuring both H.323 and MGCP on a gateway, using H.323 security features, and troubleshooting.

Chapter 4, "Session Initiation Protocol"-- This chapter describes how SIP implements call signaling, describes the various SIP functions and how they participate in the call flow, and lists the pros and cons of the protocol and when to use it. It covers implementing SIP gateways--configuring the router, using SIP toll bypass, adding the gateway to CallManager, using SIP security features, allowing SIP-to-H.323 connections, and troubleshooting SIP gateways.

Chapter 5, "Circuit Options"-- This chapter examines the various analog and digital circuits that gateways use to connect a VoIP network to the public switched telephone network (PSTN). It looks at the different signaling types, features, and uses of each type of circuit; issues such as echo cancellation; and selection and sizing of the circuit.

Chapter 6, "Connecting to the PSTN"-- PSTN connections are examined in more depth in this chapter. The analog coverage includes a discussion on configuring and troubleshooting Foreign Exchange Office (FXO), direct inward dial (DID), and Centralized Automated Message Accounting (CAMA). The digital coverage includes explanations on configuring and troubleshooting T1 and E1 PRI, BRI, and channel-associated signaling (CAS) connections. The chapter also discusses caller ID and name delivery considerations.

Chapter 7, "Connecting to PBXs"-- This chapter covers the configuration of analog PBX trunks using Ear and Mouth (E&M) and FXO interfaces, and digital PBX trunks using CAS, PRI, and BRI interfaces. It discusses Transparent Common Channel Signaling (T-CCS) and Q Signaling (QSIG).

Chapter 8, "Connecting to an IP WAN"-- This chapter covers reasons for connecting a VoIP network to an IP WAN, QoS considerations, use of the modular quality of service command-line interface (MQC) to provide the needed quality of service, and QoS over an MPLS network. Handling faxes and modems in a VoIP network are discussed. This chapter also describes the need for securing voice traffic over a WAN by using SRTP and V3PN, the implications of NAT on voice traffic, and the use of firewalls with VoIP.

Chapter 9, "Dial Plans"-- This chapter covers dial plan design and implementation. It discusses building a scalable dial plan, handling overlapping number ranges, and implementing a dial plan on gateways and call agents. It helps you understand the different types of dial peers and how they affect call routing by examining the way that the gateway selects dial peer matches.

Chapter 10, "Digit Manipulation"-- This chapter discusses various ways for a gateway to control called and calling phone numbers, including digit stripping, forwarding only a specified number of digits, prefixing digits, and expanding numbers. It also covers voice translation rules, use of regular expressions, voice translation profiles, control of the calling-line identification information, and verification and troubleshooting of digit manipulation.

Chapter 11, "Influencing Path Selection"-- This chapter covers several different ways of influencing route selection, including hunt groups, trunk groups, and tail end hop-off. The chapter examines call admission control (CAC) techniques--local CAC using maximum connections and local voice busyout; measurement-based CAC using IP SLA, PSTN fallback, and advanced local voice busyout; and resource-based CAC using Resource Reservation Protocol (RSVP) and RSVP agent, and using CAC with gatekeepers. It also discusses considerations when using POTS-to-POTS call routing.

Chapter 12, "Configuring Class of Restrictions"-- This chapter explains what COR is and how it operates. It covers using COR with CallManager Express (CME) implementations, and on a gateway with Survivable Remote Site Telephony (SRST), restricting both inbound and outbound calls.

Chapter 13, "SRST and MGCP Gateway Fallback"-- This chapter gives an overview of SRST with ways to adjust the failover and fallback times, and shows how to configure SRST on both the gateway and CallManager. It describes MGCP fallback and how to configure it. SRST dial plan considerations are discussed, along with configuring SRST call features, configuring SIP SRST, preserving calls, and troubleshooting SRST and MGCP fallback.

Chapter 14, "DSP Resources"-- This chapter examines codec considerations and configuration, digital signal processor (DSP) considerations, determination of DSP resources needed, the DSP modes, and configuration of conferencing and transcoding resources on both the gateway and CallManager.

Chapter 15, "Using TCL Scripts and VoiceXML"-- This chapter explains how to support interactive voice response (IVR) and advanced call-handling applications using Toolkit Command Language (Tcl) and VoiceXML. It gives examples, tells how to download Tcl scripts, and shows how to configure gateways to use them. This chapter also examines the auto attendant (AA) script and creation of audio files in more detail and discusses some caveats and restrictions.

Part III, "Gatekeepers"
Chapter 16, "Deploying Gatekeepers"-- This chapter provides the conceptual information that you need to integrate gatekeepers into your VoIP network. It describes gatekeeper functionality in networks with and without a CallManager, gatekeeper CAC and address resolution, redundancy and load balancing, gatekeeper security, and use of hierarchical gatekeepers. A discussion of planning a gatekeeper implementation includes placement, bandwidth, and dial plan issues. Scalabilty and multizone enhancements are also addressed.

Chapter 17, "Gatekeeper Configuration"-- This chapter is a practical guide to gatekeeper configuration. It covers router configuration for basic and advanced gatekeeper functions such as directory gatekeepers, gatekeeper redundancy, Resource Availability Indication (RAI), and security. CallManager configuration for gatekeeper use and gatekeeper redundancy is also discussed, along with ways to troubleshoot your gatekeeper implementation.

Part IV, "IP-to-IP Gateways"
Chapter 18, "Cisco Multiservice IP-to-IP Gateway"-- This chapter explains the functions of an IP-to-IP gateway, its use in service provider and enterprise environments and in CallManager networks, its use of the Open Settlement Protocol, and the way it functions with RSVP. This chapter also covers using these gateways with both H.323 and SIP, configuring IP-to-IP gateways, configuring a via-zone gatekeeper, and troubleshooting the configuration.

Awesome AVVID book
I work for a large Cisco reseller and purchase many Cisco Press books to augment knowledge base and assist with best-practices. I have to say that this book is one of the best Cisco Press books I've ever purchased and probably the best Cisco Press AVVID book.
I've been searching for a comprehensive source for DSP information and deployment guidelines, and COR theory. This book does an excellent job on explaining both. It is a must for anyone working with or provisioning DSPs.
In other matters, it is well written and talks plainly of other gateway technologies that AVVID engineers run into day-after-day.
If your looking for VoIP books, this is a must for your library.

MUST READ for CCVP and CCIE-VOICE
As someone who is very familiar with the Cisco GWGK training courseware, I found this book to be EXCELLENT! It is very, very well written and fills in a lot of the knowledge gaps that I have not found in any other Cisco Press voice books or courseware. This book is a must read for any Cisco engineer planning on deploying a Cisco voice solution!!!! The book is also perfect for preparing for the GWGK CCVP test and the CCIE-Voice.

Dennis Hartmann
CCIE# 15651