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IMS-Based Services: Service Interoperability

IMS Whitepaper blog

The rise of Long-Term Evolution (LTE) technology in mobile networks has driven the implementation of IP Multimedia Subsystem (IMS) based services on a global scale. The technology has had widespread growth across Asia, the USA and Europe with both LTE data and HD Voice services.

With these developments in the market, we think it’s essential to provide recommendations on important topics that matter to organizations and create real value that benefits the entire ecosystem. It’s about having a positive and lasting impact that helps shape the future of our industry.

Our whitepaper “IMS-based Services: Service Interoperability”, describes the architectures, interfaces and protocols that need to be adopted by Carriers for the support of international IMS services.

The IMS framework has been designed to support a set of multimedia applications and enhanced messaging in a full-IP environment. Our IMS whitepaper takes a strong focus on voice and covers both basic international call and roaming, and advanced communication services in Video over LTE (VoLTE) and Rich Communication Services (RCS).

There are new opportunities for Carriers with IMS, but there’s also complexity. By focusing on interoperability issues between two Carriers/IPX Providers or between a Servicer Provider and its IPX Providers, the document addresses:

  • The role of the international Carrier/IPX Provider and the architectural framework based on IPX
  • IMS Interface specification
  • The basic principles for Call Routing, Quality of Service control and Network Security at the application layer
  • The impact on Carrier networks in terms of call types, physical interconnection, signaling interworking, transcoding and call routing
  • Business and technical impacts of roaming scenarios approved by GSMA
  • Features and capabilities of the hubbing mode between a Service Provider and IPX Provider


Together with a companion document that’s devoted to the IMS interface definition, our whitepaper provides a unique analysis of the impact on Carriers’/IPX Providers’ platforms for the provisioning of IMS-based services.

At i3forum, we develop recommendations and guidelines that deliver valuable content for the entire international Carrier ecosystem. Our IMS group analyze the use of IMS in existing and new services as well as interoperability issues to support industry transformation with IMS-based services.


Click here to read our IMS whitepaper:


If you want to work together to create practical and tangible results that really benefit the international Carrier ecosystem then you can join our IMS workgroup here: