Sales of mobile phones with active SIP functionality will reach 275 million units in 2012, according to research released Tuesday.

Industry analyst and parent of telecoms.com, Informa Telecoms & Media, said that sales of SIP-enabled devices are set to increase from 0.4 per cent of total device sales in 2006, to 19 per cent by 2012, with a strong growth curve taking place between 2010 and 2011.

Within the mobile handset space, SIP is essentially split into two main variants, naked SIP (IETF SIP) and 3GPP SIP, which is also called IMS SIP.

Naked SIP is widely used in both the fixed and mobile telephony worlds and is an obvious choice as the basis of a convergence platform. Already in the mobile space, naked SIP is considered to be an essential component for enabling access to services such as wireless VoIP.

“The lack of control over its development and its widespread use means that many mobile network operators perceive naked/IETF SIP as a challenge to their business models,” said Malik Saadi, principal analyst at Informa.

The number of users of naked SIP services is likely to grow from 2.2 million in 2006 to more than 212 million in 2012, according to the analyst. Saadi expects this growth to be mainly driven by the strong will of device vendors to get involved in the content space – Nokia is a good example – but also by the increasing number of new entrants among VoIP and internet content providers determined to challenge the mobile operator walled-garden service offering.

“3GPP SIP on the other hand is a mobile operator led initiative is designed to create an ideal ecosystem for them to leverage the potentials of IP without losing control of their walled garden services,” Saadi said.

The number of subscribers who have embraced 3GPP SIP-based services did not exceed 1.15 million in 2006. However, mobile network operators’ growing acceptance of SIP and their relationship with mobile handset vendors will see increasing numbers of 3GPP enabled devices produced. This, in turn with the availability of 3GPP SIP services such as push services over cellular networks (PoC), Mobile Instant Messaging (MIM), Video Sharing and mobile VoIP (mVoIP) will help grow subscriber numbers further.

By 2012, the number of subscribers using 3GPP SIP based services will exceed 276 million, thus surpassing the number of IETF SIP service users, Saadi said.