Open source-based voice systems and legacy voice systems differ in numerous ways, but in this article we'll focus on some of the more practical aspects that can give your business a competitive advantage, as opposed to another troubled IT project. We'll mostly be contrasting VoIP systems comprising open source software with whatever voice system you have today, which we'll call "legacy." Your legacy system could be a traditional circuit-switched PBX or a relatively new VoIP system. But for the sake of discussion, we'll assume that whatever it is, it's proprietary.
Open source: A brief introduction
Open source software (or occasionally hardware) is technology whose uncompiled source code is freely available for anyone to inspect. The most popular example of open source software is the Linux operating system. There are thousands of other applications, however, including applications that provide all aspects of telephony. Most of them are also free. Asterisk is probably the most popular, but there are many others. If the term "open source" is completely new to you, then I recommend you check out the SearchOpenSource.com Web site.
The flexibility of open source
The first thing a voice manager leading an organization's foray into the data world needs to know about open source opportunities is that you can mix and match components. A major advantage of distributed computing is that voice applications
This means your whole IP telephony estate doesn't have to be all-proprietary or all-open source. For instance, you could have an open source Automatic Call Distributor (ACD) but use a voicemail system from one vendor and gateways from another, as well as a mix of open source soft phones and handsets from several companies -- as long as they all support a standard protocol such as H.323 or SIP. This dramatically reduces the risk that you may be associating with open source, because you can keep your mission-critical system -- a call center, for instance -- on your old, reliable, favorite vendor's gear, while saving some bucks or pushing innovation with peripheral systems.
The downside to this mix-and-match flexibility is that you must pay more attention to integration. In fact, an important part of your strategy might be using an integrator such as IBM that invests a lot in open source and is also strong in network and telephony delivery. In any event, you can pursue the flexibility and excellence of a best-of-breed solution or mix and match to get a low cost while mitigating risk.
Fast-changing technology and management challenges
The next thing you need to understand about open source is that -- compared with legacy telephony equipment -- upgrades are fast and furious. This is good because upgrades bring new features, but it also takes some management discipline to keep integration dependencies from turning chaotic.
Finally, the questions you've probably been asking all along: "Who's going to support this? Where do I go when I need help?" If you go down the integrator path, the answers are easy. If you go it alone, it's a little dicier -- but there are plenty of success stories, so it's by no means impossible.
Many open source offerings are backed by companies that turn a dollar on services (obviously, since the software is free), so you can lean on their expertise. But much as regular VoIP projects stand or fall on the strength of technical people with a mix of voice and data skill sets, adding open source to the mix means you need to add application development to your staffing plan. This is not to say you'll be coding the open source applications, but these packages are rarely turnkey -- and the configuration can often include a bit of scripting. Having someone who knows the way around development will go a long way toward smoothing any integration rough edges.
The bottom line is that -- depending on what your organization's needs are and how tolerant you are of risk -- you can leverage open source solutions to tailor a highly customized solution with the exact features you need, or you can use it to avoid a lot of license fees.
About the author: Tom Lancaster, CCIE# 8829 CNX# 1105, is a consultant with 15 years of experience in the networking industry. He is co-author of several books on networking, most recently, CCSP: Secure PIX and Secure VPN Study Guide, published by Sybex.