Cisco Press - Integrating Voice And Data Networks.pdf - Cisco Press(1) - andri98z

Integrating Voice and Data Networks

Integrating Voice and Data Networks

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Printed in the United States of America 1 2 3 4 5 6 7 8 9 0

Library of Congress Cataloging-in-Publication Number: 99-67924

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This book is designed to provide information about Voice and Data Integration. Every effort has been made to make this

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Credits

Publisher

John Wait

Editor-in-Chief

John Kane

Cisco Systems Program Manager

Bob Anstey

Integrating Voice and Data Networks

Managing Editor

Patrick Kanouse

Acquisitions Editor

Tracy Hughes

Production Editor

Marc Fowler

Copy Editor

Jessica McCarty

Technical Editor(s)

Priscilla Oppenheimer

Brian Gracely

Steve Kalman

Book Designer

Gina Rexrode

Cover Designer

Louisa Klucznik

Production Team

Argosy Publishing

Indexer

Tim Wright

Integrating Voice and Data Networks

Preface

When I began writing this book nearly a year and a half ago, the technological landscape of integrated voice and data

networks was very different. While adequate for most projects, the technology offerings were fragmented across different

product lines, and there were numerous caveats with respect to feature support and hardware requirements. For example, the

smallest Cisco router that supported T-1 voice connections and VoIP was the AS5300 Access Server. For companies that did

not have the call volume or network size to justify the price point of the AS5300, the only reasonable option was the

MC3810. At that time, the MC3810 did not support VoIP, so smaller companies that required digital PBX connections had to

choose between VoFR and VoATM.

Scaling MC3810 hub-and-spoke networks was also very awkward. Many network topologies require a single voice T-1

between the router and PBX at remote locations. To support the voice-port densities at the central site, these designs often

required stacks of MC3810 routers, tied together via back-to-back serial connections using Frame Relay switching. For larger

networks, the remote MC3810 routers could be connected to a carrier-class IGX Frame Relay switch at the central site. There

was a huge price and technology gap between the small-scale stacks of MC3810s to the large-scale carrier class WAN

switch.

Since that time, there has been a mind-boggling frenzy of product development within Cisco. Even while focusing on

voice/data integration, I have been challenged to keep abreast of new product developments and feature support. As of this

writing, there are hardware solutions to fit any price point and technology scale, from small-office/home-office (SOHO)

applications to large carrier-class, high-density voice gateways and controllers. The Cisco IOS software supports a variety of

voice signaling options across many hardware platforms, and more features are constantly being added. Aside from these

gateway advances, the Cisco AVVID program has added new dimensions to the array of products, creating new applications

that are unparalleled in old-world voice networks.

Many solid voice/data networks have been built with previous generations of Cisco IOS software and equipment. It stands to

reason that the current generation of Cisco offerings, which incorporate a multitude of improvements, is quite robust in terms

of reliability and feature support.

The largest obstacle to the development of voice/data networks is not the maturity of the products or the technology, but the

lack of experienced people who understand the technology and can take advantage of the features that Cisco routers support.

It is my hope that you will learn from this book, which in turn will advance the field of voice/data networking.

Introduction

Voice and data services have traditionally developed as isolated communications systems. In order to integrate these systems,

you must thoroughly understand how an integrated solution meets the goals and requirements of each system

Objectives

This book explains the goals and requirements of traditional voice networks, and provides information to help you develop

integrated voice/data networks that can meet these goals and requirements. Using illustrations and detailed examples, this

book explains the strengths and weaknesses of VoFR, VoATM, and VoIP as packet voice solutions.

After reading this book, you should be able to perform the following functions:

• Analyze a traditional telephony environment and propose an enhanced packet voice solution to reduce circuit

expenses and enable new applications

• Design a telephone-numbering and call-routing plan that spans traditional telephone switches and packet voice

routers

• Enable quality of service (QoS) features on Cisco routers to ensure excellent voice quality

• Establish connectivity between Cisco routers and PBXs, key systems, or Central Office (CO) phone switches using

a variety of traditional telephony signaling protocols

• Establish any-to-any calling connectivity across traditional and packet voice networks, using appropriate

connection modes to preserve features as appropriate (for example, hook-flash, stutter dial-tone for voice mail)

• Isolate and resolve voice quality issues that may be caused by any number of factors, including audio signal levels,

tandem routing, codec processing, and network QoS

Integrating Voice and Data Networks

Audience

This book is most relevant to data network engineers and managers who will design, implement, or maintain integrated

voice/data networks. This book is also appropriate for sales engineers, systems engineers, project managers, and others in the

networking industry who are involved with voice/data integration projects or wish to increase their knowledge of voice and

data networking.

You are not expected to be familiar with any aspect of traditional voice networking, except perhaps as an end user of a

business telephone with features such as call forward, transfer, and conference.

You will absorb more information from this book if you are familiar with basic data networking concepts such as the OSI 7

layer model, TCP/IP routing and addressing, and wide area networking (WAN) technologies such as T-1/E-1, ISDN, Frame

Relay, and ATM. To facilitate discussions of VoFR, VoATM, and VoIP, this book briefly reviews WAN technologies and

examines advanced IP features in detail. You are not expected to understand QoS issues prior to reading this book.

Organization

This book is organized to accommodate readers with different objectives and different technical back-grounds. The Cisco

IOS configuration details are isolated in the last part of the book, so that readers who do not need hands-on configuration

knowledge may learn the concepts without the burden of configuration details. For readers who need specific guidance while

working in the trenches, ample space is devoted to detailed explanations of Cisco IOS configuration. In addition, the book

offers practical advice that is distilled from the author's design and implementation experience in numerous production

network environments.

Part I is an in-depth examination of traditional telephony standards, protocols, and methodologies as they apply to corporate

enterprises, and to a limited extent, service providers.

Part II builds the conceptual foundation for real-time packet voice communication over data networks, including QoS issues

and call signaling requirements. The operation of VoFR, VoATM, and VoIP (including H.323 and SIP) are described in this

part of the book.

Part III considers the early phases of a voice/data integration project, including discovery, analysis, planning, and design

issues.

Part IV is devoted to the implementation phase of voice/data integration projects, and delves into the specifics of Cisco IOS

router configuration. Several appendixes provide useful troubleshooting information that is inadequately documented in other

sources.

Approach

This book is intended to complement the documentation that is currently available from Cisco Connection Online (CCO).

Given the detailed references that are already available for individual commands, this book does not exhaustively define the

configuration options for each voice-related command. Rather, the most relevant commands are described from the

perspective of what functions they enable or what problems they solve. The focus of this book is to build an organized

conceptual framework that helps you make sense of many interrelated technologies.

I learn new topics and retain knowledge better when I understand how and why something works. I do not like to memorize

command sequences or follow a ritualized process unless I know what I am doing and why I am doing it. For this reason, I

have tried to emphasize the why and how wherever possible in this book.

I recognize that there are many ways to think and learn, and that some people prefer to learn the essentials without laboring

through details. However, if you try to learn this material by memorizing a set sequence of tasks, then you may be stuck

when you encounter a new situation or a variation of a familiar situation. I have endeavored to instill in you a deeper level of

knowledge that you can use to resolve unfamiliar obstacles and more quickly grasp related subjects.

Cisco Press - Integrating Voice And Data Networks.pdf

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