Book Image

Asterisk 1.4 - the Professional's Guide

Book Image

Asterisk 1.4 - the Professional's Guide

Overview of this book

Asterisk is the leading Open Source Telephony application and PBX software solution. It represents an effective, easy-to-administer, and accessible platform for running enterprise telephony requirements. The real world, however, offers numerous hurdles when running Asterisk in the commercial environment including call routing, resilience, or integrating Asterisk with other systems. This book will show you some of the ways to overcome these problems. As the follow-up to Packt's highly successful 2005 title Building Telephony Systems with Asterisk, this book presents the collected wisdom of Asterisk Professionals in the commercial environment. Aimed at Administrators and Asterisk Consultants who are comfortable with the basics of Asterisk operation and installation, this book covers numerous hands-on topics such as Call Routing, Network Considerations, Scalability, and Resilience ñ all the while providing practical solutions and suggestions. It also covers more business-related areas like Billing Solutions and a Winning Sales Technique. Even if your interest or experience with Asterisk is lower level, this book will provide a deeper understanding of how Asterisk operates in the real world. Asterisk is deployed across countless enterprises globally. Running on Linux, it has constantly demonstrated its resilience, stability, and scalability and is now the advanced communication solution of choice to many organizations and consultants. With a foreword from Mark Spencer, the man behind Asterisk, this book presents the accumulated wisdom of three leading Asterisk Consultants and shows the reader how to get the most out of Asterisk in the commercial environment. Over the course of eleven chapters, this book introduces the reader to topics as diverse as Advanced Dial Plans, Network Considerations, and Call Routing, through to Localization, DAHDI, Speech Technology, and Working with a GUI. The book also covers the more nebulous aspects of being an Asterisk professional such as evaluating customer requirements and pitching for contracts. This book represents the wisdom and thoughts of front line consultants. The knowledge they impart will prove informative, thought provoking and be of lasting interest to Asterisk professionals.
Table of Contents (20 chapters)
Asterisk 1.4
Credits
Foreword
About the Authors
About the Reviewers
Preface
9
Interfacing with Traditional Analog and Digital Telephony
Sample Appointment Sheet

Internal calls


These calls are by far the easiest to route. For internal calls in the same office it is simply a case of using the LAN and we have already discussed how to ensure your LAN is up to the task in Chapter 2.

If you are making inter-office calls, then the best route depends on the quality of the company WAN, if there is one. A WAN with good bandwidth between offices can have a single central Asterisk server handling all the extensions. It's a simple setup, and all resilience efforts can be focussed on a core server. However, losing connectivity to an office will mean that all telephone services at that office are lost. This risk can be alleviated by introducing resilience into the WAN links too, a measure which increases ongoing circuit costs.

As we can see from this diagram, traffic from the branch office traverses the WAN to reach the PBX at the head office where it will be routed via the Internet if appropriate (for example if the call is external and to be routed via an ITSP...