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December 2006, Volume 9/ Number 12

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VoIP: All Mixed Up

By Joel A. Pogar


Heterogeneous VoIP may sound like something you need a vaccination for, but it�s one of the latest buzzwords circling the IT industry. It�s hard to refute that Voice over IP (VoIP) has taken off in the last few years. Many businesses, big and small, have adopted VoIP for the features and cost savings it has to offer. As the VoIP industry has grown, so have the number of VoIP vendors. Just a few years ago, there were only four or five serious VoIP product vendors; now there are over a dozen and the list keeps growing. Even Microsoft (News - Alert) plans to enter this market in a big way with the release of its next Windows operating system, scheduled for 2007.

With the corporate economy rebounding, and an increase in the number of mergers and acquisitions, it was only a matter of time before companies ended up managing more than one VoIP system. It�s not uncommon for companies in strong growth industries to be grappling with three or more different VoIP systems. This can present challenges with incompatible gateways, redundant voicemail, and inoperable unified messaging systems � basically two or more VoIP environments that can�t communicate. But what should an IT or Telecom department do? Can different VoIP systems work together? Should everything be replaced? While the answers are varied and complex, depending on which systems and vendors are involved, there are some common issues to consider when integrating disparate VoIP systems.

First and foremost, decide on a standard. If you are currently managing multiple VoIP systems, pick one. No matter what vendors tell you about open standards and interoperability, it�s better to manage a single system. One of the biggest advantages of VoIP is cost savings, but cost savings begin to dwindle when managing multiple environments. Disparate VoIP systems may require specialized hardware or software for interoperability and then only offering limited functionality. Such a set-up will ultimately erode the return on investment offered by VoIP, in addition to creating the usual headaches associated with integration and maintenance of two or more systems. Remember, VoIP vendors are aggressively competing for market share today. While most vendors are trusted business partners in your enterprise, some will be willing to sell, or tell you, anything not to lose handsets on the desktop. So, evaluate proposed interoperability solutions carefully, especially if the information is coming from the vendor that may be displaced.

Another consideration is to keep an open mind when evaluating the systems in your environment. The phone system you started with does not have to be the phone system you end up with. If the company you are acquiring has a better VoIP solution, consider adopting their technology as the standard. Too often, IT and telecom managers have an emotional attachment to the system they developed from the ground up. Be objective and think about the business needs of both companies before making a final decision on an equipment standard.

When evaluating different VoIP systems, the protocol being used could be an easy decision maker. There are two common protocols in VoIP systems today: SIP and H.323. A significant percentage of VoIP systems are using SIP, but that does not mean that all of them are. Furthermore, early VoIP systems used proprietary versions of SIP or H.323. So, even if both systems are using SIP or H.323 that still does not mean they will work together. Don�t forget to look at the big picture. If your entire telecom environment is heavily weighted toward one protocol or another, changing protocols could add significant delays and expenses to a conversion project.

Not only do the phone systems have to be considered, but any unified messaging, voicemail and security systems also need to be evaluated. Maybe the phone systems are compatible but the voicemail and security architecture are not. Ensure your voicemail and security systems can accommodate the new system, especially if it requires a change in VoIP protocols. Before any implementation or conversion begins, the network of the acquired party should be thoroughly examined. Don�t take for granted that everyone uses �best practices� for the initial deployment of VoIP. If the proper network infrastructure is not already in place, such as adequate bandwidth, VLAN segmentation, and QoS, you may be fighting a losing battle. Don�t spend hours, days, or weeks trying to figure out why two seemingly compatible VoIP systems can�t communicate, only to find out the network was not properly designed in the first place. It happens more than you think.

Finally, if it�s decided that one system needs to be replaced, work with your vendor, or telecom provider, for trade-in discounts on the old system. VoIP vendors will offer trade-in discounts, especially for competitive gear. Typically, 10-40% discounts can be achieved when trading in your old system. While some companies try to manage this themselves, it�s more efficient to let the vendor do it if they have a trade-in program.

While most VoIP professionals advocate the use of a single system for ease of deployment and maintenance, that�s not always possible. Heterogeneous VoIP environments can and do work. Making an educated decision and evaluating all of the criteria are the keys to success. Be sure to evaluate more than just the hardware, and consider what is in the best interest of both companies being united. IT

Joel Pogar is a director in Forsythe�s network solutions and security practice. For more information, please visit the company online at

If you are interested in purchasing reprints of this article (in either print or PDF format), please visit Reprint Management Services online at or contact a representative via e-mail at [email protected] or by phone at 800-290-5460.


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