Book Image

FreeSWITCH 1.2 - Second Edition

Book Image

FreeSWITCH 1.2 - Second Edition

Overview of this book

FreeSWITCH is an open source telephony platform designed to facilitate the creation of voice and chat-driven products, scaling from a soft-phone to a PBX and even up to an enterprise-class soft-switch. It is always exciting to design and build your own telephony system to suit your needs, but the task is time-consuming and involves a lot of technical skill."FreeSWITCH 1.2" comes to your rescue to help you set up a telephony system quickly and securely using FreeSWITCH. It is rich with practical examples and will give you all of the information and skills needed to implement your own PBX system.You will start with a detailed description of the FreeSWITCH system architecture. Thereafter you will receive step-by-step instructions on how to set up basic and advanced features for your telephony platform.The book begins by introducing the architecture and workings of FreeSWITCH before detailing how to plan a telephone system and then moves on to the installation, configuration, and management of a feature-packed PBX. You will learn about maintaining a user directory, XML dial plan, and advanced dial plan concepts, call routing, and the extremely powerful Event Socket. You will finally learn about the online community and history of FreeSWITCH."FreeSWITCH 1.2" is an indispensable tool for novice and expert alike.

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FreeSWITCH 1.2 - Second Edition
May, 2013 | 428 pages
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Table of Contents (24 chapters)
FreeSWITCH 1.2
FreeSWITCH 1.2
Credits
Credits
About the Authors
About the Authors
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Architecture of FreeSWITCH
Architecture of FreeSWITCH
A revolution has begun and secrets have been revealed
The FreeSWITCH design – modular, scalable, and stable
Important modules – Endpoint and Dialplan
Complex applications made simple
Summary
2
Building and Installation
Building and Installation
Setting up the FreeSWITCH environment
Operating system prerequisites
Text editors and XML
Downloading the source
Building from the latest code
Compiling FreeSWITCH for Linux/Unix/Mac OS X
Compiling FreeSWITCH for Windows
Starting FreeSWITCH
Running FreeSWITCH in the background
Summary
3
Test Driving the Example Configuration
Test Driving the Example Configuration
Important concepts to understand
Putting FreeSWITCH to work
Configuring a SIP phone to work with FreeSWITCH
Testing the example Dialplan
Summary
4
SIP and the User Directory
SIP and the User Directory
Understanding the FreeSWITCH user directory
Working with the FreeSWITCH user directory
User features
Adding a user
Testing voicemail
Groups of users
Connecting to the world with gateways
SIP profiles and user agents
Summary
5
Understanding the XML Dialplan
Understanding the XML Dialplan
FreeSWITCH XML Dialplan elements
Contexts
Extensions
Call legs and channel variables
Accessing channel variables
Regular expressions
Actions and anti-actions
How Dialplan processing works
Creating a new extension
Important Dialplan applications
Dialstring formats
Summary
6
Using XML IVRs and Phrase Macros
Using XML IVRs and Phrase Macros
IVR engine overview
IVR XML configuration file
IVR engine overview
Using phrases with IVRs
Advanced routing
Summary
7
Dialplan Scripting with Lua
Dialplan Scripting with Lua
Getting started with Lua
Basic Lua syntax
Building voice applications
Advanced IVR concepts
Scripting tips
Summary
8
Advanced Dialplan Concepts
Advanced Dialplan Concepts
Dialplan overview
General Diaplan concepts
Putting it all together
XML Dialplan module review
Pitfalls to avoid
XML Dialplan applications
Utilizing variables
Global variables
Dialplan functions
Set, export, and legs
Passing variables via call headers
XML Dialplan cookbook
Summary
9
Moving Beyond the Static XML Configuration
Moving Beyond the Static XML Configuration
The mod_xml_curl basics
The mod_xml_curl Dialplan
The mod_xml_curl folder
The mod_xml_curl configuration
The mod_xml_curl summary
Generating configurations dynamically with language bindings
Making calls from the command line interface
Using ESL to execute commands
Summary
10
Controlling FreeSWITCH Externally
Controlling FreeSWITCH Externally
General overview
Event system architecture
Event-based modules
Sending events
Events from the Dialplan
FreeSWITCH event system commands
FreeSWITCH Console application
Event Socket Library
Events in practice
Summary
11
Web-based Call Control with mod_httapi
Web-based Call Control with mod_httapi
HTTAPI syntax
mod_httapi configuration file
The demo IVR – in HTTAPI
Summary
12
Handling NAT
Handling NAT
A brief introduction to NAT
The four pitfalls of NAT
Demystifying NAT settings in FreeSWITCH
Making media flow
Advanced options and settings
FreeSWITCH on the client side
Other creative uses of FreeSWITCH in a NAT situation
Conclusion
Summary
13
VoIP Security
VoIP Security
Network level protection
Protecting SIP signalling
Protecting audio
Protecting passwords
Summary
14
Advanced Features and Further Reading
Advanced Features and Further Reading
Multi-user conferencing
Nibblebill
Alternative endpoints
Configuration tools and related projects
Web GUIs
Supporting libraries
Vestec Automatic Speech Recognition
Summary
The FreeSWITCH Online Community
The FreeSWITCH Online Community
The FreeSWITCH mailing lists
Talking in real time via IRC
The FreeSWITCH main website and wiki
The annual ClueCon open source developer conference
Migrating from Asterisk to FreeSWITCH
Migrating from Asterisk to FreeSWITCH
Getting started
Configuration files
Two SIP phones
Voicemail
Summary
The History of FreeSWITCH
The History of FreeSWITCH
Taking things to the next level
New ideas and a new project
The first ClueCon
Introducing FreeSWITCH
Index
Index

Scripting tips

There are a few things to keep in mind when working with Lua scripts from the Dialplan:

  • When a Lua script is finished, the call automatically hangs up. If you wish for the Dialplan to continue processing, be sure to execute session:setAutoHangup(false). Consider the following Dialplan snippet:

    <condition>
    <action application="lua" data="my_script.lua"/>
    <!--the following is not executed unless setAutoHangup is 
      false -->
    <action application="transfer" data="$1 XML default"/>
</condition>

  • The proper way to exit a Lua script is for the script to run out of commands. As of the previous edition of this publication, there was no explicit command to exit a script; however, you may now use the error() function to force the script to terminate. If session:setAutoHangup(false) has been set, then the Dialplan will continue to process.

  • Keeping the previous point in mind, note that calling session:bridge() or session:transfer() may not work...

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