Goodbye PBX, Hello IT Architecture - InformationWeek
IT Leadership // CIO Insights & Innovation
09:10 AM
Marty Parker
Marty Parker

Goodbye PBX, Hello IT Architecture

It's time to embrace a new enterprise communications model and ditch the old one. Here's why, in the first of a multi-part series.

Let's face facts: The PBX is obsolete. The time has come to move on to higher-function, lower-cost business communications. 

For the past 50 years, the PBX was a way for companies to avoid costly telephone company facilities or optimize their use. It was proprietary; PBX phones connected only to each vendor's branded system. Vendors rationalized that proprietary approach by claiming that it assured reliability and enabled them to deliver a rich set of voice communication features. That rationale is no longer valid.

Today, PBX vendors offer the illusion of aggressive innovation by using Internet Protocol, but for the most part they have simply replaced one digital communication protocol (time division multiplexing) with another (IP) and rebranded their systems. The new "IP PBXs" remain proprietary, and they're still saddled with costly recurring maintenance fees closely controlled by the vendor and its distributors. 

[Revamping your communications? Read Unified Communications Plans: 6 Ways To Derail Disaster.]

To stay relevant, the PBX vendors have tried to embrace non-real-time communications such as instant messaging, email, collaborative workspaces, and social media, under the banner of unified communications and collaboration. But these applications were already well developed by leading software vendors. Adding them to PBX configurations turned out to be a fruitless strategy.

PBX vendors also added video and online conferencing to their product suites, but again their efforts were limited by proprietary system architectures and proprietary non-video desktop phones. Even as the PBX vendors scrambled to catch up, users were already enjoying videoconferencing services over the Internet via their companies' non-PBX video systems, PCs, laptops, tablets, and recently even smartphones.

A new IT architecture for enterprise communications has disrupted the old PBX model, similar to the evolution in computing systems. Here's what it looks like:

  • Voice media streams are now digitized with standards-based Internet Protocol. Conversations flow between devices over any Internet connection, using LAN/WAN bandwidth management to maintain voice quality, and using media encryption to assure security. 
  • User devices can be any computing product -- desktop PCs, laptops, tablets, smartphones, IP phones. 
  • Calls are set up using standards-based directories.
  • Services such as telephony features, conferencing, and recording are provided by software modules running on general-purpose servers or virtual machines. 
  • Voice media streams flow to users on the wired and cellular public telephone networks via IP gateways.
  • Internet (Ethernet) bandwidth commonly exceeds the requirements for real-time communications, so dedicated voice telephony networks are no longer necessary. 
  • The new architecture is modular and standards based, so it can be distributed on-premises or in the cloud to deliver high performance, economy, and reliability. 

The chart below depicts this evolution to the new enterprise communications architecture. The conventional PBX architecture is shown on the left as a vertically integrated stack -- produced, sold, and serviced by single vendors and their distributors.

The new layered communications system model is shown on the right as a stack of capabilities, similar to how most enterprise software applications are deployed. For each layer, only two or three typical vendors are listed, but competition is fierce, lowering costs and driving innovation. The layered model also benefits from economies of scale because each layer serves the entire communications and IT market, not just the customers for a single PBX brand. For example, any app can use IP devices (PCs, tablets, smartphones), servers, and LANs/WANs.    

The arrows in the chart map the evolution from the single-brand PBX model to

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Marty Parker, Principal and co-founder of UniComm Consulting, has more than three decades of experience with computing and communications technologies. He has been a leader in strategic planning and product line management for IBM, AT&T, Lucent, and Avaya. Now, as ... View Full Bio
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