Switching to VoIP

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

xvi

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Preface

• A description of the core technologies of digital telephony—sampling, pulse

code modulation, time division multiplexing, trunking, and call signaling

• Examples of how VoIP networks overlay IP networks and how voice applica-

tions reside within the OSI network model

• An explanation of why many early VoIP adopters’ implementations didn’t live

up to expectations

• An introduction to the two subsets of VoIP standards: audio transmission and

signaling

• Introductions to SIP, H.323, and other signaling specifications that are com-

monly used in IP telephony

• Some practical strategies for justifying VoIP adoption in a business scenario

• An introduction to IP hardphones, analog telephone adapters, softPBX servers,

and the other devices that make VoIP systems tick

• Strategies for dealing with quality-of-service issues, including policy-based, pro-

tocol-based, and practice-based approaches to ensuring tip-top operational qual-

ity of a VoIP network

• Information about interfacing VoIP systems with traditional phone equipment

and the public telephone system by way of analog trunks and T1 lines

• The basics of enforcing low-layer security in a VoIP environment, with examples

for IP Tables firewalls

• Tips for gauging VoIP readiness on an enterprise network or over an Internet

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