Open Source and VoIP

Updated: August 20, 2012

The Open Source Software (OSS) movement started in the old days of the Internet. The philosophy of OSS is that the source code for any given program should be made freely available to the public for alteration and improvement. The idea behind this type of freedom is that anyone should be able to alter the source code, but it does not necessarily mean that no one can charge money for programs. In contrast to traditional software development, which is carried out by teams of highly paid developers privately at a company, OSS is developed by anyone who has the desire to contribute.

The argument for OSS is that due to the global nature of the Internet, the number of "eyeballs" that can contribute to any given project is much higher than that of a private company. In 1998 the Netscape Navigator source code was released to the public and Mozilla (the browser ancestor of Firefox) was born; along with the coining of the term, Open Source Software.

Asterisk is by far the most visible OSS VoIP technology. Asterisk is industry standard PBX software whose open source codebase is maintained and managed by Digium . It allows connectivity on both PSTN and VoIP networks, and has countless advanced features. Asterisk was created by Mark Spenser as a telephony solution that he built from scratch for his startup business. When he made the code available to the public, it proved to be so useful that it soon dominated the market. Although Asterisk is available for free in its unadulterated form, getting a version that is easily implementable by most users will cost some money. Users also need to pay for support, which is how most OSS business models function.

A more recent VoIP application of OSS is FreeSwitch. FreeSwitch was written by Anthony Minessale II, a developer who, after contributing to other telephony related open source projects, decided to start a new initiative that focuses on abstraction, modularity and cross-platform cross-architectural design. This application allows users to make calls from their computer to regular telephones, something that had previously been impossible except with a proprietary softphone.

Another company that uses OSS is Sphere. This company uses SIPfoundry, a PBX that is more standards-compliant than Asterisk, but its business model stresses the sentiment that open source means free as in freedom, not free as in beer .

In an interview with Andy Mercker, Director of Marketing at Sphere, he said, "At Sphere, we actually take a different strategy. We offer a free Web Services SDK (software development kit) that enables rapid integration with other enterprise-class business applications." He said that Sphere is a user and contributor to open source VoIP projects, but also makes money from it. For Sphere, these things are not mutually exclusive.

Mercker spoke about the way that Sphere uses OSS, "The implication of our Web Services SDK is that now people seeking to dramatically advance their business capabilities through integrated communications can do so through a significantly easier and more familiar process. By making the capabilities of our IP PBX available through Web Services, we have abstracted the complexities away from the interfaces so that application developers simply import our WSDL into their development environment to enable business applications with advanced communications features including voice, video, presence, and much more. This is in sharp contrast to the "brute force" hard coded application-to-application integration via traditional APIs which require software developers to have deep technical knowledge of the underlying PBX."

There are countless other OSS VoIP applications, such as sipXphone , Partysip , or Vovida . VoIP, as a new and disruptive technology, shares many of the user-first components of OSS. Because of these similarities, the Open Source community has adopted VoIP as a poster child for how efficient a method of software development OSS can be. It has been successful so far and the waves of developers who are intrigued by the possibilities of VoIP development have continued to pour in.

On the future of Open Source VoIP, Kevin Fleming of Asterisk said, "As the Asterisk market continues to grow rapidly on a daily basis, we saw the need to expand the team managing the open source project. By identifying these key community members to participate in our council, we can ensure that the project continues to add innovations and improve without any delays."

The implications of open source for VoIP are great. There is a lower cost of entry into the market. The cost of owning and running equipment and software is reduced. Users have the ability to freely customize standard tools and shared groups of developers can collaborate on solutions for future developments.

But there are still disagreements about levels within open source. In an interview with Dave Clarke, Business Development Manager for PIKA, he spoke about the way PIKA uses OSS, "We use Open Source in our Grand Prix. It is a high level API with a BSD license. BSD almost has no restrictions at all." About the differences between licenses he said, "The GPL license is bad. We want to give our customers a choice to remain closed source."

The GPL or Gnu Public License is the least proprietary, most consumer-oriented license, and it places strict limits on closing source code. Often said to be the most evangelical of licenses, the GPL aims to keep software code open above all else.

About this Clarke said, "When using GPL we have to be fairly careful how we use it in our products. People want to make money. That's one of the challenges on the open source." And this seems to be the line that companies walk, how to maximize the benefit of using the Open Source community, while still holding on to the ability to close or restrict the source code when it is time to market a product. Making money is important, but for some the appeal of open source goes beyond the bottom line. On the topic of free software Clarke said, "Free is definitely a big thing for most people. The Linux world has proven that just because it is free doesn't mean it is cheap. Open source tends to get a lot more eyeballs."

One theme that has come out of OSS because this is that if someone does the integration, installation, and configuration work for themselves, then software is freely available. For some VoIP technologies, however, installation and integration can prove to be exceedingly difficult. This is where there is an opportunity for income. For most businesses it is cheaper to pay someone else to set up their Open Source PBX, and tailor it to the specific needs of the company, than for the businesses to do it themselves. This is part of the spirit of OSS as well. If you do the work, you should reap the reward.