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The future of IP telephony still trapped in the PBX era

The future of IP telephony and the IP PBX is still locked in the PBX era. Enterprises need to stop treating IP telephony systems like TDM systems.

Of all the discussions I have with IT decision makers regarding Voice over IP (VoIP), the most common set of questions...

tends to revolve around the future of the IP PBX—and who can blame anyone for wondering? The telephony industry has had more innovation and transformation in the past 10 years than in the 30 years previous to it, which makes keeping up very challenging.

I fully expect the pace of innovation to continue and even accelerate, making it even more difficult for enterprises to anticipate what the future of the voice platforms will be and position themselves accordingly. I'd like to provide some insight into what I think the future of IP telephony and the IP PBX will be.

The failed promise of IP PBX

Deploying voice used to be easy. You plugged your phones into a PBX, and it all magically worked. The problem with these older PBX platforms was that they were highly inflexible, inefficient and had to be deployed on a location-by-location basis. There was no way to extend features past the installed location, and they had to be run on an entirely separate network.

Then along came the IP PBX, which was supposed to be the panacea to all of our telephony woes. By converging voice and data networks, the cost of running telephony would drop through the floor. We would get more functionality and users would be more productive. It would be a win for IT, the users and the company—but this was not the case for many organizations.

Depending on who you talk to, the amount of cost savings tends to vary. The upfront costs are high, and in many cases, there isn't all that much new functionality. We make calls, but we could do that before. So what's held us back?

I think the main drag on the industry is that we really have not left the PBX era. Sure, all of the new systems are built on IP. We have new (and expensive) IP phones, but architecturally, not much has changed. A large number of the organizations I have worked with deploy VoIP by replacing every PBX or key system with an IP PBX. So at the end of the day the entire architecture is the same; we're just using IP as the transport mechanism instead of the PSTN, but at the most basic level, we've spent a great deal of energy trying to make our IP systems look and act like the old TDM systems.

The evolution of the PBX

The first wave of evolution away from the PBX era followed along the same path as computing. We deployed the new platforms, but kept the architecture the same. Much of this was due to gaining comfort with the new systems, but the IP PBX platforms themselves weren't ready to support a different architecture.

I think the main drag on the industry is that we have not really left the PBX era.

Zeus Kerravala
Senior Vice President and
Distinguished Research Fellow
Yankee Group

The next wave of VoIP will be similar to what happened in the computing world. Call servers will become data-center based resources that use the corporate WAN to deliver services to the branches and other workers. Think of any other application in the organization, like email or CRM systems—all of these reside in the data center and are delivered over the network.

The technology evolution has also contributed to this trend. All of the new voice platforms—such as Avaya Aura, Cisco Unified Communications Manager and Microsoft Lync—are designed to be deployed this way. They follow application and Web principles to allow greater scale and efficiency.

The other important thing to note about these platforms is that they do more than just initiate and tear down calls. A next-generation IP PBX should be thought of as an IP session manager and not a call server. Calls are one of the features enabled by the IP session, but the session brings the ability to layer on video, presence and other multimedia functions.

Since the session is at the IP layer, it becomes highly mobile and can be moved from a phone to a tablet to a PC with relative ease. This will bring with it another level of cost savings and start to fulfill the long-term vision of what the move to IP was supposed to be: connecting any communications tool to any user on any device. But in order for that to happen, there needs to be another evolutionary step, which we are just starting to see.

IP PBX: Opening minds to open platforms

In the long term, I think the industry will stop thinking about the PBX as a closed system and instead see it as set of open platforms that work together to deliver the necessary functionality.

To clarify my point, I'll again use the application world as an example. In most large organizations, application strategies are the same. An underlying services layer provides all of the common functions, such as authentication and directory services. Above this layer, applications are built on a few platforms, such as .NET or Java. Middleware is then used to tie it all together. Though this is a gross simplification of how applications work, and there are all kinds of exceptions, this is the primary route most companies take.

Similarly in communications, what we will eventually have is a common-services layer for things like presence and user identity, some of which will be shared with other applications. A set of platforms will sit above this layer—perhaps one for voice, one for video, one for social media—with a higher-level, abstraction layer for the middleware functionality. In fact, Avaya's ACE, VOSS and Alcatel-Lucent's OpenTouch are good examples of some early communications middleware.

Though we're a long way off from this, it is the direction the industry is headed. Are we out of the PBX era? Hardly, but we're rapidly moving that way.

Zeus Kerravala, Senior Vice President and Distinguished Research Fellow, Yankee GroupAbout the author: Zeus Kerravala, Yankee Group senior vice president and distinguished research fellow, leads the firm's Research Council and is chartered with the responsibility of providing thought leadership to the research organization. Comprising senior research leaders, the Research Council provides outreach to clients and the broader Yankee Group community, as well as ensures that the company's research agenda addresses the needs of business leaders. Kerravala drives the strategic thinking of the research organization and helps shape the research direction. Much of Kerravala's expertise involves working with customers to solve their business issues through the deployment of infrastructure technology.

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