According to the report, expanding demand will also fuel growth of VoIP deployments as IP telephony gains popularity in businesses of all sizes. But despite growing over the next couple of years, PBX sales will plateau come 2009, the report indicates.
"Dell'Oro Group projects that revenue for the PBX market will peak in 2009 and flatten out through 2011," the report states. "As VoIP matures, more functionality is leaving the core PBX switch and moving data equipment onto the LAN or into software running outside the PBX switch, either in services running in the enterprise core or on phones."
When sales level out, vendors will have to adapt.
"In 2006, we saw numerous announcements from vendors heading toward a more software-oriented PBX -- for example, by offering increased functionality via software that differentiated their PBX from a competitor's or additional features incorporated inside data network equipment," the report says.
In general, IP PBX sales will strengthen the most. Other PBX segments are expected to fall short, however. For example, hybrid IP/TDM PBX revenues are expected to decline, starting in 2010; and by 2011, traditional PBXs are projected to make up less than 5% of the overall market -- a massive decline from 2002, when the traditional PBX segments accounted for more than 85% of market revenues.
"Large enterprises have led the way in the deployment of IP telephony, and now we are seeing SMBs also realizing the benefits of VoIP," said a statement by Alan Weckel, analyst of IP telephony enterprise research at Dell'Oro Group.
Dell'Oro expects IP lines to become the majority of shipments and IP PBX and Hybrid IP/TDM PBX to constitute more than 80% of the installed base in 2011.
UC will also play a significant role as companies seek to integrate voice with other communication modes, such as instant messaging and video, and other collaborative applications, such as email and messaging.
Weckel said companies are going out and buying IP PBXs today in an attempt to future-proof and roadmap for future UC capabilities that may not necessarily be on their radar screens today. Companies are looking to UC both to boost productivity and enable more collaboration, he said.
"UC could have a significant impact on the enterprise voice market and on all the vendors that currently sell into it," the report states. "Currently, UC plays a more important role in larger system deployments than in the SMB because large enterprises have the IT staff to install and maintain the necessary components."
Dell'Oro Group said UC adoption will take time because many products and services need extra time to mature. The release of Microsoft's Office Communication Server will ease UC deployments for SMB markets, however, because of simpler installation and maintenance.
"It is reasonable to believe that UC will be the next disruptive technology in voice and that the market share and positioning of current vendors will change during the forecast period," the report states.
Weckel added: "Large enterprises are testing the waters with Unified Communications solutions that promise to provide users with a cohesive communications experience in which voice, instant messaging, video and email are integrated together."