JKL-5 Group

Q2 2010 Issue, Volume 1, Part 1

Enterprise Dialing - The Advantage of Adding Another Asterisk PBX

As a pop-culture humor line goes, "you're doing it right" if your company is growing. Some of that growth is going to eventually be geographic; across town, across the province or state, across the country or across the globe. Or maybe you've got plans for a modern "Work 2.0" style of office with some or all of your staff either working from home or from "work clusters".

One of the biggest restrictions that many companies face when planning geographic growth of any kind is the increased cost of communications, the forefront of which, traditionally, was the price of a new PBX. Right after that was the long-distance bill between the head office and the remote staff or office. In addition, there was the aggravation of now having seven or ten digit dialing to speak to someone you needed to do daily business with.

The good news is that with Asterisk-based VoIP telephony, all of those headaches go away. In addition, if your new system is properly conceived, you even gain features.

At the heart of the entire arrangement are three pieces. The first is the Internet itself. The Internet was first concieved as a military network designed by academics in the late 1960's and early 1970's. Today, the Internet is a commercialized space composed of a network of networks that consists of millions of private, public, academic, business, and government networks of local to global scope.

One of the wide variety of services carried over the Internet is Voice Over IP (VOIP). VOIP allows calls to be made at no additional cost than the network connection between any two or more points on the globe. Since most 21st century businesses are fully "Internet enabled", this generally imposes no extra costs.

The second piece of the puzzle is the Asterisk PBX system. Asterisk is the world's most popular open source telephony project. Under development since 1999, Asterisk is free, open source software that turns an ordinary server-class computer into a feature-rich voice communications server. Asterisk makes it simple to create and deploy a wide range of telephony applications and services.

Code for Asterisk, originally written by Mark Spencer of Digium, Inc., has been contributed to from open source software engineers around the world. Currently boasting over two million users, Asterisk supports a wide range of telephony protocols. Unlike traditional telephone systems, Asterisk was built from the heart outwards to be a VOIP PBX.

The last piece is a technology known as DUNDi. DUNDi stands for "Distributed Universal Number Discovery", which is a fancy way of saying "PBXs know how to tell each other what phones are where". Each PBX in a DUNDi network asks its neighbouring peer whether it knows how to reach a certain phone extension or phone number that the local PBX does not recognize. The DUNDi protocol was also invented by Mark Spencer. Therefore the syntax of the output of a DUNDi-network lookup can be directly used in the dial commands in an Asterisk Dial Plan.

Put all together, it could look like this: The corporate head-office is in New York, USA, with a branch office in Montreal, Canada and another in London, England. All of the company phones are in the 1000-2999 range, in no particular geographic tie-in. In other words, it's a phone system where 1000 is the switchboard in New York, 1002 is a secretary in Montreal and 1005 is an accountant in London and around and around as people were hired and left and extension numbers were recycled.

For a traditional phone system, this is a nightmare that causes a lot of headaches in HR maintaining a phone list which is actually implemented by telephony which is a sub-department of IT. For Asterisk + DUNDi, however, this is simple. No matter where a phone is on the network, when the user dials a number -- be it a corporate extension number or an external phone number -- the same process happens.

Lets say that the user at extension 1000 dials 1002. The New York PBX checks its own dial-plan and cannot find a 1002. So, it asks the other servers on the same DUNDi cloud "Does anyone know where 1002 is?" The Montreal PBX answers "Yes, I have it, pass the call to me." The two servers then negotiate an IAX2 VOIP connection across the Internet, and the two parties are talking across 730km instantly at no long distance cost and no need to remember the office number in another country.

Perhaps a businessman at the Montreal office needs to book a room at a Bed-and-Breakfast in London, England, for an upcoming business trip. The Montreal PBX looks at the number and realizes 011 is an international dial. It immediately asks the DUNDi cloud "Does anyone know about 44 20 'something' as a phone number?" The London PBX replies back "Yes, that is a local call to me, pass me the call." Again, the two servers then negotiate an IAX2 VOIP connection across the Internet. This time, the PBX in London uses one of its business lines to make the call locally. This saves potentially between 10 and 20 cents per minute of the call. Just think of the money saved while you're on hold.

The combination of Asterisk + DUNDi + Internet VOIP allows remote workers to have an office phone without the office. In the next "5 Points Ezine", I'll explain how you can deploy remote workers, handle "roadwarriors" and even run a call center with no chairs.

If you'd like to find out more about how "Enterprise Dialing" can be implemented at your company, please call us!

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