Networks Group


The Networks Group (NG) specifies technical, operational, and performance requirements to support international roaming and interworking, taking into account technology evolutions.

The NG focuses on compatibility and interoperability aspects of the signalling and inter-working of roaming between Public Land Mobile Networks and public switched networks.

The group defines profiles, guidelines, and test procedures for voice and data services to provide a better experience to users for mobile services. The services include those from Rich Communication Services (RCS).

In addition to that, the group specifies a common infrastructure abstraction and exposure of a set of capabilities, resources, and interfaces offered by an operator’s virtualisation/cloud infrastructure.

The group encompasses a number of sub-working groups working on the various topics in their remit and complies with the specification policy and procedures related to Industry Specifications.

The group is made up of mobile operators and vendors (equipment and terminal manufacturers) from all various regions of the world.


Key Topics

The Networks Group is currently working on:

  • LTE and 5G voice, video and messaging services
  • LTE and 5G roaming
  • Network Slicing (Generic network Slice Template – GST)
  • Analysis and solution providing of real issues faced by Operators related to VoIMS (e.g. VoLTE, Vo5GS, VoWiFi using mobile core) and other IMS services interoperability
  • Management of technical document exchange tool, Roaming Agreement Exchange
  • Revision and simplification of Roaming test Documents.
  • Identification of needs and requirements for NNI selection and ENUM
  • Needs and requirements on Diameter – Radius interworking and Service Based Architecture
  • Definition of KPIs for Data roaming and VoIMS.
  • QoS and Global Roaming Quality
  • Steering of Roaming network aspects
  • Security aspects related to inter-PMN network architecture
  • 2G/3G networks aspects including closure considerations
  • Mobile IoT roaming and testing
  • Wi-Fi profiles (WLAN access connected to mobile core) and Roaming
  • VoIMS debugging and evolution
  • LTE based Aerial profile support (e.g. for drones)
  • 5G non-public networks for verticals/industry support
  • Cloud Infrastructure Reference Model to support 5G services (e.g. edge cloud)

What the Networks Group Does:

  • Profiles (based on IMS) and guidelines for the above key topics
  • Call/session handling scenarios including for interworking between mobile systems from different generations
  • Testing end-to-end functional testing of services (including, supplementary services).
  • Maintenance of existing test suites Interworking.
  • Signalling (circuit/packet) issues related to inter-working with or without roaming, to ensure appropriate level of end service.
  • User plane (circuit/packet) issues related to inter-working with or without roaming to ensure appropriate level of end service.
  • Definition of QoS requirements between networks for seamless roaming.
  • Signalling and inter-working requirements between PLMNsand PSTN.
  • Compatibility and interoperability of PLMN’s with different protocol versions and service facilities Addressing & Numbering.
  • Circuit switched and packet switched addressing.
  • Creating and maintaining operator’s numbering/addressing databases (i.e.: IR.21).
  • Defining migration scenarios when new addressing schemes are introduced
  • Ensure the appropriate end-to-end network features for the support of services.
  • Definition, development and maintenance of Rich Communication Suite’s Services
  • Documents approval according to recent Industry Specification process for selected documents


The Networks Group have face to face meetings and are held twice a year. NG sub-working groups have face to face meetings four times per year with additional meetings/conference calls if needed.

How to Get Involved

If you would like more information on any of the Networks Group activities, please contact  If you are interested in contributing and attending Networks Group meetings then please contact to become a GSMA Member.  Communications including liaison statements should be sent to

Sandra Ondrusova

Networks Group Chair, Hutchison 3G UK Limited

Javier Sendin

Networks Group Director, GSMA

Karola Rajoo

Assistant Working Groups Manager, GSMA