(1/5)VoIP – An overview of the fast evolving technology
February 11th, 2014 // 6:23 pm @ Arad Gharagozli
In this series of article, I will try to share what I have learnt so far as opposed to reiterate the basics of VoIP that is widely available on web. For the purpose of this discussion and upcoming articles, I will be using Asterisk, the Free opensource VoIP service, that is widely used around the world.
If you are reading this article, there is a strong chance that you already know what VoIP (Voice over Internet Protocol) is. VoIP is a technology that enables the user to create a network of IP enabled phones (as opposed to PBX). Then, these phones can communicate to each other via a central server that can handle the requests and organizes the calls. There are several organizations that make servers for VoIP services, such as MetaSwitch, CISCO, etc… of course, do not confuse the servers with service providers, there are plenty of companies out there who provide VoIP service, but again, their infrastrcutre is based on other company’s server, like MetaSwitch.
One of the most famous servers in the VoIP world is the Asterisk PBX. Asterisk was created in 1999 by Mark Spencer, and is written in C. It’s multi-platform, and most importantly comletely FREE. Although Digium took over Asterisk, but it’s still available under GNU Public License version 2 (GPLv2) license.
Asterisk supports SIP ( Session Initiation Protocol) and IAX(Inter-Asterisk eXchange) standard, and can perform on top of a CentOS as a stack very nicely! In fact, you can find the complete stack called Free-PBX Asterisk here ==> https://www.freepbx.org/downloads/ \
Since Asterisk is widley used worldwide, there is a lot of support out there, also, from my own experience I agree with Asterisk when they say “Build your VoIP using Asterisk, and the sky is your limit”. I don’t think I ever came across a problem in design, and Asterisk didn’t have a solution for it. In the VoIP series, I will try to cover mostly hands on and practical aspect of the Asterisk, and by the end of this tutorial you should be able to have a fully functioning Phone network.
By the end of this series you should feel comfortable with:
- How to setup Asterisk (using OpenPBX)
- How to Configure the Asterisk
- How to Configure your phone/Softphone
- Debugging
- How to call from one phone to another (Within Asterisk network/LAN/WAN)
- Adding Video Calling to your Asterisk
- SIP Trunks/SIP Bindings – Extend your Asterisk
- What is DID and how to get a public phone number (recieve phone calls)
- How to dial into PSTN (public switched telephone network)
Category : VoIP - telephony
