The rise of VoLTE and VoWiFi

VoLTE and VoWifi have been long promised by the Telecom industry and vendors, but it’s only recently that their need has become more urgent than ever. Now that some 3G networks are seeing their sunset, the number of VoLTE capable devices has grown significantly and consumers have become familiar with data-only plans, VoLTE is developing rapidly as the only real option of keeping voice services available for customers as we go to 4G or 5G only networks.

While in 2017 less than 10% of all global mobile network subscribers were VoLTE-based, it is forecasted that due to the increasing decommissioning of 3G networks more than 80% of all phone calls will be VoLTE-based by 2025. According to Allied Market Research, Voice over Long Term Evolution (VoLTE) market is expected to garner $34.8 billion by 2022, registering CAGR of 50.1% during the forecast period 2016 - 2022.

However, implementing a VoLTE/VoWIFi solution is not a simple task as both MNOs and MVNOs have to put together all elements needed as they are provided by separated vendors. This results in long and complicated projects and delayed go-to-market. Besides, the need for fallback to 3G generates complexities in the operational models.

To solve these shortfalls, X2ONE and Summa Networks have partnered to jointly develop an integrated, fully virtualized, and cost-effective VoLTE / VoWiFi solution: voLTEinabox.

Solution Description

Diagram voLTEinabox

Multi-generational HSS/HLR

  • All subscriber data management needs are covered into a single software suite, which combines LTE HSS, IMS HSS, HLR and UDM in a single software suite, allowing seamless interworking between 3G, 4G, 4.5G and 5G.
  • 3GPP release 15.
  • Complete offering for GSM, UMTS, LTE, IMS, Wi-Fi and M2M networks.
  • Support for multi-SIM, multi-IMSI, multi-MSISDN, multi HPLMN/country, multi-profile and virtual routing instances.
  • AAA server for diameter protocols.
  • Authentication Center (AuC).
  • Equipment Identity Register (EIR).

IMS core and application servers

  • IP-SM-GW – provides SMS services for VoLTE and legacy devices; allows interworking towards other networks based on SMPP and legacy devices; allows interworking towards other networks based on SMPP.
  • MMTel/ TAS – provides rich supplementary services, e.g. call-forwarding and call barring; acts as a conference-factory for VoLTE handsets.
  • MRF – provides network announcements and conferencing; implemented according to RFC4240; set up as combined MRF-controller (MRFC) and -processor (MRFP).
  • SR-VCC – enables seamless early or mid-call handover from 4G/5G to 2G/3G; acts as a media-anchor for voice calls.
  • LI – provides X1 to X3 interfaces towards the mediation function.
  • PCRF light*: given its mandatory nature to deploy VoLTE, our solution includes a lightweight PCRF with only an Rx and Gx interface.
  • ePDG light*: the ePDG allows untrusted access to the IMS as required for Voice-over-WiFi (VoWiFi); standalone solution independent of the EPC.
* Under development

Integration points

voLTEinabox sits in the core of a carrier network and, as a general scenario, integrates with:

  • MME / PGW / SGW: to receive the requests for calls from the devices in the network.
  • OCS: for charging purposes.
  • OSS/BSS: an API for Subscribers provisioning and management is available.
  • Optionaly, and depending on customer network architecture it might integrate as well with an SBC or other elements.

Unique benefits

Flexible deployment model

Our solution can be deployed in bare metal, as a fully virtualized solution and as lightweight containers (Docker Swarm, Kubernetes) to run on any public or private cloud (e.g. Oracle, Amazon, RedHat, etc.) as well as on any server environment. This enables the carrier to unbundle software and hardware / Cloud infrastructure.

Standard-based and flexible

Our solution is 100% standard-compliant based on 3GPP, SIP, and has been integrated with the hardware and software of all legacy suppliers. This provides the highest possible flexibility to integrate both with legacy architecture and innovative (open-source) applications.

Customer Focused

Our agile product development and deployment process enables us to incorporate new client requests quickly - ca. 80% less time compared to legacy suppliers - and co-develop new solutions.

Cost-effective and flexible commercial model

We offer the most competitive commercial VoLTE-solution in the industry.


Our software components are carrier-grade to guarantee the highest possible uptime.


We can scale up our clusters from a few thousand to millions of subscribers.

Our Satisfied Customers


Summa Networks

Summa Networks is the market specialist in Subscribers, Policy and Identity Management. Our mission is to guide carriers of all sizes and types in their transition towards 5G, while they still need to operate on 2G, 3G, 4G, 5G NSA networks until ready to upgrade to 5G SA, first as an overlay function in hybrid interworking mode, then as pure 5G Standalone. Today, more than 30 mobile (virtual) network operators worldwide trust our mobile core solutions.


X2ONE Israel is an Israeli based company who created the X2ONE platform. The X2ONE platform is designed to provide telecom carriers such as MNOs, MVNOs, Voip Carriers, ISPs and the like, with a single software based platform covering all aspects of the service and business needs.


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