roderickm September 13th, 2007

The first question we hear from visitors is invariably, “if you give away your software, how do you make money?” Good question, and one that presents a great opportunity to explore the challenges of being a truly open source company today. Mark’s ha-ha-only-serious answer is, “Any way we can.”

How does it all work? How are Digium and Asterisk connected?

Digium’s revenue directly funds open source Asterisk development. Digium is far and away the leading sponsor and contributor to Asterisk, and we foster the community of outside contributors as well. Better software attracts more customers, which funds additional Asterisk development, and the cycle continues.

We’ve found some compelling ways to generate that revenue and keep the cycle growing. Today, Digium sells:

• support, training, & integration services for customers that rely on Asterisk;
• hardware interfaces that allow an Asterisk installation to talk to phones and the telephone network, along with other voice processing hardware and software;
• the AA50 Asterisk Appliance, a complete embedded Asterisk PBX that began shipping this summer;
• Asterisk Business Edition, a tested, commercially-licensed, and supported version of Asterisk.

Let’s focus on that last one, since it’s the one that seems to stump people, the same people that think open source is about pinching pennies. After all, why pay for a commercially-licensed version of Asterisk when the open source version doesn’t cost a dime to download? Glad you asked!

Open source is much more about freedom than it is about price. The most common open source license — and the one under which Asterisk is licensed — is the GPL, which requires that the source code be available to anyone that receives the software. You have the freedom to modify the software and redistribute it as long as you follow this basic GPL rule. (There are a few others, but this is the biggie.)

However, the license also says, “This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.”

So what happens when you want to rely on Asterisk in your business? When you think you have found a bug? When you need help making Asterisk talk to your SQL database? You have the Asterisk source code available to you… but not everyone writes C code. (I surely don’t.) You can engage the community on a mailing list, and convince, cajole, or bribe someone into helping. But good programmers that also know telephony are generally busy people, so this may not fit your schedule.

Digium has the answer: with a dual-licensing model, Digium alone is able to distribute Asterisk legally outside the GPL. Asterisk Business Edition is exhaustively tested for performance, stability, and compatibility in Digium’s Product Quality Labs, and is then released as a commercially-licensed binary-only package. ABE includes an entire rPath Linux + installer combination for easy installation as a software appliance. It is supported by a dedicated Technical Support team, and it is backed by Digium’s commitment to our customers. When a rare bug is identified in ABE, it is escalated to Engineering for resolution, then the update is made available to ABE customers… and these patches are likewise folded back into open source Asterisk.

Bugs reported against open source Asterisk are handled by the community at large, while ABE bugs are handled by Digium with high priority. This offers the best of both worlds: you can test-drive open source Asterisk, prove that it does exactly what you need, then become an ABE customer before deployment in a production network. Do you know any proprietary vendors that send you their source code before you buy?

Altogether, I encourage those who can to participate in the Asterisk open source community: it’s a wonderful group. If you plan to exercise the freedoms that open source offers, by all means, grab open source Asterisk and enjoy. Engage and enrich the community. But if you’re interested in open source Asterisk solely because it’s distributed at no charge, you probably have the wrong expectations.

Digium exists to serve its customers, so if you need reliable help from the Asterisk experts, I invite you to become a Digium customer. We’ll take great care of you.

• ABE , Community