Asterisk 1.6

Barrie Dempster, David Gomillion, David Merel

• Publisher: Packt Publishing
• Year: 2009
• eBook ISBN: 9781847198624
• Edition: 1
• Topic: Informatik
• Subtopic: Informationstechnologie

In Detail

Asterisk is a powerful and flexible open source framework for building feature-rich telephony systems. As a Private Branch Exchange (PBX) which connects one or more telephones, and usually connects to one or more telephone lines, Asterisk offers very advanced features, including extension-to-extension calls, queues, ring groups, line trunking, call distribution, call detail rerecords, and call recording.

This book will show you how to build a telephony system for your home or business using this open source application. 'Asterisk 1.6' takes you step-by-step through the process of installing and configuring Asterisk. It covers everything from establishing your deployment plan to creating a fully functional PBX solution. Through this book you will learn how to connect employees from all over the world as well as streamline your callers through Auto Attendants (IVR) and Ring Groups.

This book is all you need to understand and use Asterisk to build the telephony system that meets your need. You will learn how to use the many features that Asterisk provides you with. It presents example configurations for using Asterisk in three different scenarios: for small and home offices, small businesses, and Hosted PBX.

Over the course of ten chapters, this book introduces you to topics as diverse as Public Switched Telephony Network (PSTN), Voice over IP Connections (SIP / IAX), DAHDI, libpri, through to advanced call distribution, automated attendants, FreePBX, and asterCRM.

With an engaging style and excellent way of presenting information, this book makes a complicated subject very easy to understand.

An easy introduction to using and configuring Asterisk to build feature-rich telephony systems for small, medium and large businesses

Approach

The book offers readers both a detailed description as well as step by step instructions on deploying software solutions as well as Asterisk configurations. Screenshots are provided in sections to give a visual perspective of the instructions. For Asterisk configurations actual sample code is listed in the book which can be directly inserted into your Asterisk solution.

Who this book is for

This book is aimed at anyone who is interested in building a powerful telephony system using the free and open source application, Asterisk, without spending many thousands of dollars buying a commercial and often less flexible system.

This book is suitable for the novice and those new to Asterisk and telephony. Telephony or Linux experience will be helpful, but not required.

Asterisk 1.6

David Gomillion

Barrie Dempster

David Merel

---

Table of Contents

Asterisk 1.6

Credits

About the Authors

About the Reviewer

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code for the book

Errata

Piracy

Questions

1. Introduction to Asterisk

What is Asterisk?

What's new in Asterisk 1.4?

What's new in Asterisk 1.6?

Asterisk is a PBX

Extension-to-Extension calls

Line trunking

Telco features

Advanced Call Distribution

Call Detail Records

Call recording

Call parking

Call barging

Asterisk is an IVR system

Asterisk is a call center system

Asterisk is a voicemail system

Asterisk is a Voice over IP (VoIP) system

Asterisk 1-2-3

Asterisk scalability

Asterisk does not run on Windows

Is Asterisk a good fit for me?

Trade-offs

Flexibility versus ease of use

Graphical versus configuration file management

Calculating total cost of ownership

Return on Investment

Summary

2. Making a Plan for Deployment

The Public Switched Telephony Network (PSTN)

Connection methods

Plain Old Telephone Service (POTS) line

Integrated Services Digital Network (ISDN)

T1 or E1

Voice over IP connections

Determining our needs

Terminal equipment

Types of terminal devices

Hard phones

H.323

SIP

IAX

Soft phones

Analog adapters

Another PBX

Choosing a device

Features, features, and more features...

Requirement elicitation

Requirement prioritization

Requirement documentation

Phone testing

Determining true cost

Compatibility with Asterisk

Sound quality analysis

Usability issues

Recording decisions

How much hardware do I need?

Choosing the extension length

Preparing a test environment

Summary

3. Installing Asterisk

Preparing to install Asterisk

Obtaining the source files

Installing DAHDI

Installing LibPRI (optional)

Installing Asterisk

Getting to know Asterisk

Summary

4. Configuring Asterisk

DAHDI interfaces

system.conf

Lines

Terminals

chan_dahdi.conf

Lines

Terminals

SIP interfaces

IAX interfaces

Voicemail

Music on hold

Queues

Conference rooms

Summary

5. Creating a Dialplan

Creating a context

Creating an extension

Creating outgoing extensions

Advanced Call Distribution

Call queues

Call parking

Direct Inward Dialing (DID)

Automated attendants

System services

Summary

6. Quality Assurance

Call Detail Records

Flat-file CDR logging

Database CDR logging

Monitoring calls

Recording calls

Legal concerns

Summary

7. Making Asterisk Easy to Manage

Trixbox

CentOS

Trixbox preparation and installation

What is FreePBX?

FreePBX preparation and installation

FreePBX System Status Dashboard

Tools

Setup

Trixbox maintenance section

Reports

Asterisk Recording Interface

Flash Operator Panel (FOP)

Flash operator configuration files

Web MeetMe

Setting up and accessing Web MeetMe through Trixbox

Flexibility when needed

A simple one-to-one PBX

Extensions

Trunks

Routes

Summary

8. What is asterCRM?

Installing asterCRM

Automatic installation

Manual installation

Introducing asterCRM

Import

Statistic

Extension

Customer

Dialer

System

Survey

Summary

9. Case Studies

Small office/home office

The scenario

The discussion

The configuration

system.conf

chan_dahdi.conf

musiconhold.conf

voicemail.conf

modules.conf

extensions.conf

Conclusions

Small business

The scenario

The discussion

The configuration

system.conf

chan_dahdi.conf

musiconhold.conf

agents.conf

queues.conf

sip.conf

meetme.conf

voicemail.conf

extensions.conf

Conclusions

Hosted PBX

The scenario

The discussion

The configuration

system.conf

chan_dahdi.conf

musiconhold.conf

sip.conf

voicemail.conf

extensions.conf

Conclusions

Summary

10. Maintenance and Security

Backup and system maintenance

Backing up configurations

Backing up voice data

Backing up log files

Backup scripts

Time synchronization

Adding it all to cron

Back up Asterisk with FreePBX

Back up Asterisk with Trixbox

Rebuilding and restoring the Asterisk server

Disaster Recovery Plan (DRP)

Asterisk server security

Internal access control

Host security hardening for Asterisk

Integrity checker

Rootkit detection

Automated hardening

Role Based Access Control (RBAC)

Network security for Asterisk

Firewalling the Asterisk protocols

SIP (Session Initiation Protocol)

H.323

IAX

The Real-Time Transport Protocol (RTP)

Controlling administration of Asterisk

Asterisk scalability

Load balancing with DNS

Support channels for Asterisk

Mailing lists

Forums

Internet Relay Chat (IRC)

Web sites

Digium

Summary

Index

Asterisk 1.6

Copyright © 2009 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors, Packt Publishing, nor its dealers or distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: September 2009

Production Reference: 1160909

Published by Packt Publishing Ltd.

32 Lincoln Road

Olton

Birmingham, B27 6PA, UK.

ISBN 978-1-847198-62-4

www.packtpub.com

Cover Image by Raghuram Ashok (<[email protected]>)

Credits

Authors

David Merel

Barrie Dempster

David Gomillion

Reviewer

Justin Thomas Zimmer

Acquisition Editor

Louay Fatoohi

Development Editor

Swapna V. Verlekar

Technical Editors

Conrad Sardinha

Neha Patwari

Copy Editor

Sanchari Mukherjee

Indexer

Rekha Nair

Hemangini Bari

Editorial Team Leader

Gagandeep Singh

Project Team Leader

Priya Mukherji

Project Coordinator

Ashwin Shetty

Proofreader

Chris Smith

Graphics

Nilesh Mohite

Production Coordinator

Shantanu Zagade

Cover Work

Shantanu Zagade

About the Authors

David Merel is the founder and CEO of Thinkbright LLC a local/long distance telephone company as well as a cutting-edge Voice over IP carrier, providing businesses of all sizes with sophisticated and low cost VoIP solutions.

David started Thinkbright (www.thinkbright.net) in 2005 and continues to manage the company and its employees, all of whom are dedicated IT professionals. David acts as the company's chief architect, continually designing new technologies that have added significant revenues to the company's operations. During his many years at Thinkbright, David has worked with the latest Voice over IP technology, including all VoIP equipment from major manufacturers such as Cisco, Polycom, Grandstream, and Aastra. He also works with customers ranging from small businesses to Fortune 500 companies, and interacts with system integrators and IT consultants who call Thinkbright on a daily basis for assistan...

Table of contents

• Asterisk 1.6