As it turns out, there is indeed a fair amount of open source UC software out there, some of which appears more “baked” than others.
Below are three contenders that seem to have significant followings. We are not about to claim this is an exhaustive list, but they do appear to be viable options if you want to go the open source route for your UC implementation.
Asterisk by Digium
Asterisk appears to be among the oldest open source UC implementations, dating back to code developed in 1999 by Mark Spencer. Spencer is founder and CTO of Digium, based in Huntsville, Ala., which develops and distributes Asterisk code, along with UC products based on Asterisk.
From the Asterisk web site:
Asterisk turns an ordinary computer into a communications server. Asterisk powers IP PBX systems, VoIP gateways, conference servers and is used by small businesses, large businesses, call centers, carriers and governments worldwide. …
Asterisk is like a box of Legos for people who want to create communications applications. It includes all the building blocks needed to create a PBX, an IVR system, a conference bridge and virtually any other communications app you can imagine.
Users are free to implement the open source Asterisk software themselves, turn to an Asterisk integrator or consultant, or buy a complete solution from Digium, which claims its offerings cost as much as 80% less than traditional vendors. The company claims more than one million Asterisk-based communications systems are in use in more than 170 countries.
That’s a believable claim, judging from this long list of Asterisk system vendors around the world at VoIP-Info.org.
SIPfoundry Hybrid Cloud
SIPfoundry is another relative long-timer in the open source UC space, founded in 2004 in Massachusetts. Its sipXecs platform offers the gamut of UC applications, include VoIP, video and web conferencing, “presence enabled everything,” and support for mobile devices.
SIPfoundry has a slick, professional web site – far from a given in the open source space – and makes a lot of hay over the idea that it supports hybrid public/private cloud environments. From it’s web site:
Already sipXecs is used by over a million people in thousands of companies worldwide who consistently report a reduction of overall cost of up to 80% after making the transition. The main reason for the cost savings? Resource efficiency in the cloud. A massive reduction in the number of hosts required, and a massive reduction in the resource footprint of the application combined with a high degree of automation and orchestration led to a significant reduction in labor. The result is a solution that IT people like.
The company focuses on enterprise organizations and has a special focus on education, listing schools including Colorado State and Holy Cross among its users.
Elastix by PaloSanto Solutions
Another apparently well-established solution is Elastix, based in Ecuador. At the time of this update, the company says its open source solutions are deployed in more than 100,000 servers.
Its UC solutions include VoIP, instant messaging, voicemail, mail server, video conferencing, virtual conference rooms, call recording, PBX interconnection, caller ID, fax-to-email and more. Its English-language web site provides a lot of information and a robust community for support.
Those are the most popular open source UC implementations that I found. If I missed your favorite, or you have experience with any of the above, by all means share your thoughts in the comments below.