Switching to VoIP

Based on real-world experience, this handy solutions manual addresses the common VoIP migration challenges. Find out how to build your own VoIP system, install it, and begin making calls. It is helpful for IT managers, network engineers, and system administrators.

* migrating applications like voicemail and directory services
* retro-interfacing to traditional telephony
* supporting mobile users
* security and survivability
* dealing with the challenges of NAT To help you grasp the core principles at work, Switching to VoIP uses a combination of strategy and hands-on "how-to" that introduce VoIP routers and media gateways, various makes of IP telephone equipment, legacy analog phones, IPTables and Linux firewalls, and the Asterisk open source PBX software by Digium. You'll learn how to build an IP-based or legacy-compatible phone system and voicemail system complete with e-mail integration while becoming familiar with VoIP protocols and devices. Switching to VoIP remains vendor-neutral and advocates standards, not brands. Some of the standards explored include:
* SIP
* H.323, SCCP, and IAX
* Voice codecs
*802.3af
* Type of Service, IP precedence, DiffServ, and RSVP
*802.1a/b/g WLAN If VoIP has your attention, like so many others, then Switching to VoIP will help you build your own system, install it, and begin making calls. It's the only thing left between you and a modern telecom network.

Foreword

Preface

1. Voice and Data: Two Separate Worlds?

The PSTN

Key Systems and PBXs

Limits of Traditional Telephony

VoIP in the Home

VoIP in Business

VoIP's Changing Reputation
Key Issues: Voice and Data: Two Separate Worlds

2. Voice over Data: Many Conversations, One Network

VoIP or IP Telephony

Distributed Versus Mainframe

Key Issues: Voice over Data: Many Conversations, One Network

3. Linux as a PBX

Free Telephony Software

Installing Legacy Interface Cards

Compiling and Installing Asterisk

Monitoring Asterisk

Key Issues: Linux as a PBX

4. Circuit-Switched Telephony

Regulation and Organization of the PSTN

Components of the PSTN

Customer Premises Equipment

Time Division Multiplexing

Point-to-Point Trunking

Legacy Endpoints

Dial-Plan and PBX Design

Key Issues: Circuit-Switched Telephony

5. Enterprise Telephony Applications
Application Terminology

Basic Call Handling

Administrative Applications

Messaging Applications

Advanced Call-Handling Applications

CTI Applications

Key Issues: Telephony Applications

6. Replacing the Voice Circuit with VoIP

The "Dumb" Transport

Voice Channels

Key Issues: Replacing the Voice Circuit with VoIP

7. Replacing Call Signaling with VoIP

VoIP Signaling Protocols

H.323

SIP

IAX

MGCP

Cisco SCCP

Heterogeneous Signaling

Key Issues: Replacing Call Signaling with VoIP

8. VoIP Readiness

Assessing VoIP Readiness

Business Environment

Network Environment

Implementation Plan
Key Issues: VoIP Readiness

9. Quality of Service

QoS Past and Present

Latency, Packet Loss, and Jitter

CoS

802.1q VLAN
Quality of Service

Residential QoS

Voice QoS on Windows

Best Practices for Quality of Service

Key Issues: Quality of Service

10. Security and Monitoring

Security in Traditional Telephony

Security for IP Telephony

Access Control

Software Maintenance and Hardening

Intrusion Prevention and Monitoring

Key Issues: Security and Monitoring

11. Troubleshooting Tools

VoIP Troubleshooting Tools

The Three Things You'll Troubleshoot

SIP Packet Inspection

Interoperability

When, Not if, You Have Problems-

Simulating Media Loads

Key Issues: Troubleshooting Tools

12. PSTN Trunks

Dial-Tone Trunks

Routing PSTN Calls at Connect Points

Timing Trunk Transitions

Key Issues: PSTN Trunks

13. Network Infrastructure for VoIP

Legacy Trunks

VoIP Trunks

WAN Design

Disaster Survivability

Metro-Area Links

Firewall Issues

Peer-by-Peer Codec Selection

Key Issues: Network Infrastructure for VoIP

14. Traditional Apps on the Converged Network

Fax and Modems

Fire and Burglary Systems

Surveillance Systems and Videoconferencing

Voice Mail and IVR

Emergency Dispatch/911

Key Issues: Traditional Apps on the Converged Network

15. What Can Go Wrong?

Common Problem Situations

Key Issues: What Can Go Wrong?

16. VoIP Vendors and Services

Softphones and Instant Messaging Software

Skype

Other Desktop Telephony Software

Developer Tools and SoftPBX Systems

VoIP Service Providers

Telephony Hardware Vendors
17. Asterisk Reference

How Asterisk Is Supported

Asterisk's Configuration Files

Asterisk Dial-Plan

Asterisk Channels

The Asterisk CLI

Integrating Asterisk with Other Software

Key Issues: Asterisk Reference

A. SIP Methods and Responses

B. AGI Commands

C. Asterisk Manager Socket API Syntax

Glossary

Index