Communications vendor Avaya is leading the enterprise telephony and unified communications (UC) markets, according to a report from the Dell'Oro Group.

The analyst defines UC as the integration of voice with other real-time communication tools. These may include video, email and instant messaging and Dell'Oro tracked the revenue of a number of top vendors, including Cisco, Nortel, Alcatel-Lucent and Siemens.

The report found that worldwide revenue for UC during 2008's third quarter was $3.1bn (£2.1bn). Avaya led the way with 22 per cent of the market, more than three points clear of its nearest rival.

The report also collated results for the global PBX market, covering IP and legacy telephony, as well as hybrid technologies. The report found Avaya led the way in total PBX revenues by six points, the fifteenth consecutive quarter the New Jersey-based vendor has come out on top.

Dell'Oro director Alan Weckel said: "It is reasonable to believe that UC will be the next disruptive technology. UC is bringing functions that have historically been confined to core PBX hardware into software applications.

"The companies that can lead in this transition, and deliver the responsive, real-time communications features that companies want, are best positioned to compete in the new era of business communications."