The number of subscribers to retail voice over IP (VoIP) services rose by 83 per cent during 2005 according to research from analyst firm, Point Topic.

Subscriptions rose from 10.3 million at the beginning of 2005 to over 18.7 million subscribers worldwide by the end of the year Point Topic said.

Point Topic’s research has also estimated the number of people paying for PC-to-phone calls during 2005 at over 4.7 million. When combined with the retail VoIP total, this increases the overall VoIP paying subscriber totals to just under 24 million, compared with 14.4 million a year previously.

The analyst said that Japan, France and the USA continue to dominate the VoIP market in terms of subscriber numbers. A spokesman from Point Topic explained that the French market’s acceptance of the technology was largely fuelled by the country’s unbundling strategy, while Japan “led in VoIP principally because of a deal Yahoo Japan/Softbank rolled out two years ago which provides VoIP in such a way that the customer doesn’t notice [they are using an alternative technology].”

But other European nations, notably Germany, the Netherlands and Norway had begun to see a significant number of VoIP subscribers by the end of 2005. Many of these markets were reporting strong growth for early 2006. Many markets, especially in the USA and Europe, should see significant growth in VoIP during 2006, Point Topic said.

France is the biggest market in Europe, with over 2.8 million estimated paying VoIP subscribers, not including Skype users. In the UK, BT’s VoIP service had a relatively slow start in 2005 but is, according to Point Topic, doing well in 2006

Retail VoIP numbers more than doubled in the US and Canada during 2005 with the troubled Vonage leading the pack.

A handful of equipment vendors and US CDMA operator Verizon Wireless have banded together to take IP Multi-media Subsystem (IMS) technology to the next level.

Verizon, together with Cisco, Lucent Technologies, Motorola, Nortel and Qualcomm, is working to develop enhancements to the emerging IMS architecture.

The next generation architecture has been termed A-IMS (Advances to IMS) and aims to provide solutions to implement next generation services in current networks, as well as creating a foundation for the efficient roll out of both SIP and non SIP-based services in future networks.

The current outputs of the task force are a concept document and an architecture document that are being provided to industry players. The task force companies plan to make necessary standards contributions in the immediate future.

Paul Mankiewich, chief technology officer, Lucent Technologies Network Systems Group said: “We recognise the benefits of this collaboration, particularly in terms of multi-vendor interoperability, as we move into an all-IP mobility world. This effort continues to enable the delivery of blended voice, video, data and multi-media applications, what we call Blended Lifestyle services, to mobile end users.”

Industry analysts are speculating that Canadian vendor Nortel may be planning to spin off its UMTS business following rumours of organisational changes within the company.

Nikos Theodosopoulos, analyst with investment bank UBS, said that he has received information which suggests that Nortel has organisationally separated the GSM and UMTS access businesses, “a move that may presage a potential spin-off/disposal of the UMTS access business”.

Nortel is one of the largest vendors which has remained noticeably uninvolved in the recent spate of equipment manufacturer mergers. The recently announced four year strategic alliance between Nortel and Microsoft as well as a focus on enterprise channel partnerships, indicate that the enterprise space continues to be an area of increasing focus.

Motorola is another manufacturer that has not participated in any of the mega-mergers that have seen Lucent and Alcatel and Nokia and Siemens come together in recent months. But the vendor yesterday formed a UMTS kit partnership with Chinese vendor Huawei, which could be an indicator of future strategy.

Nortel has also been wrong-footed this week by the departure of the vice president and general managers for WiMAX and Converged Core Networks including IMS. No replacements have yet been identified and the developments could put Nortel in a predicament as UBS points out that both IMS and WiMAX are two of three key strategic areas of focus for Nortel.