Alcatel-Lucent reported it had shipped more than 125 million VoIP subscriber licences around the world, more than half of which were accounted for by Voice over LTE (VoLTE) technology.

The Franco-US supplier said it had shipped more than 88 million VoLTE subscriber licences.

VoLTE, an all-IP approach to voice connectivity, holds out the promise to network players of reducing operational costs, particularly if they can phase out their circuit-switched domains.

And suppliers also typically argue that VoLTE helps operators ‘control’ the voice aspect of mobile services, rather than ceding ownership to OTT players who have enjoyed success with VoIP offerings.

Another VoLTE advantage, said Alcatel-Lucent, is it frees up spectrum for mobile broadband and developing services such as HD voice and videoconferencing.

In an Infonetics Research report, cited by Alcatel-Lucent, the supplier was flagged up as the industry revenue leader for IMS, call session control function and IMS voice application servers for calendar year 2013.

IMS-based VoLTE, backed by GSMA, has widespread industry support but commercial rollout has so far been limited to operators such as MetroPCS and SK Telecom.