A majority of telecom carriers (91 percent) surveyed plan to run voice over LTE (VoLTE) services over IMS in the next two years, according to IHS, which added VoLTE is the number-one driver for deploying IMS today. In India, Reliance Jio is the first mover in the IMS space, and it has adopted the IMS solution from Nokia to offer VoLTE services. Incumbent telcos-Bharti Airtel and Vodafone India--have recently selected Nokia to deploy IMS solution for VoLTE deployment in select circles. While Jio has already started offering VoLTE services, incumbent telcos are currently trialling the service.
IHS recently conducted in-depth interviews with global service providers that have deployed IMS core equipment in their networks or will do so by the end of 2018, capturing their plans, purchase considerations and opinions of IMS vendors.
According to the results, only 17 percent of operator respondents to the IHS IP multimedia subsystem (IMS) study are currently running IMS network elements in a network functions virtualization (NFV) environment. However, respondent use of IMS in NFV environments will grow to 78 percent by 2018, driven by the ability to scale services up and down quickly and also operational efficiencies.
Operators worldwide continue to deploy and expand IMS networks for a variety of services, but mobile has become king and VoLTE is driving the majority of new activity.
"As the largest driver for IMS, VoLTE is dictating the challenges and product requirements. And the biggest challenges to IMS are migrating legacy subscribers and justifying capital expenditures on a new network for a service (voice) that represents declining revenue. Although IMS is still viewed as complex, requiring significant system integration and vendor interaction, it exposes larger challenges as operators look to move all their subscribers to IP," Diane Myers, senior research director, VoIP, UC and IMS, IHS Technology, said in an analysis.
The findings reveal that fixed-line voice over IP (VoIP) service continues to be the mainstay of IMS deployments. The transition from fixed-line VoIP to mobile services over IMS is happening, but in a measured fashion.
The business case for the services is challenging to establish. Today, 57 to 65 percent of operators surveyed run residential voice over broadband, Session Initiation Protocol (SIP) trunking or hosted business VoIP over IMS, growing to 87 to 91 percent by 2018.
"The operator world is quickly converging with fixed and mobile services," Myers said.