IP and Interconnectivity

SIP Trials

Networks Group


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

The Networks Group focuses on compatibility and interoperability aspects of the signalling and inter-working of roaming between Public Land Mobile Networks, Public Switched Telephone Networks, Integrated Services Digital Networks, Public Packet Switched Networks and any Service Supplier.

The group defines guidelines and test procedures for voice and data services and works to solve any technical problems that could impact mobile services.

Key Topics

The following work items within the Networks Group are currently being worked on:

  • Long Term Evolution voice services
  • Long Term Evolution roaming
  • Analysis and solution providing of real issues faced by Operators related to VoLTE interoperability
  • Management of technical document exchange tool, Roaming Agreement Exchange
  • Data off and IMS Services Group
  • Revision and simplification of Roaming test Documents.
  • Identification of needs and requirements for NNI selection and ENUM
  • Identify needs and requirements on Diameter – Radius interworking
  • Definition of KPIs for LTE Data roaming and VoLTE.
  • Wi-Fi Roaming
  • VoLTE debugging and evolution

What the Networks Group Does:

  • Testing end-to-end functional testing of bearer services, teleservices and supplementary services.
  • Maintenance of existing test suites Interworking.
  • Circuit Switched signalling issues related to inter-working with or without roaming, to ensure appropriate level of end service.
  • Connectionless signalling issues related to inter-working with or without roaming to ensure appropriate level of end service.
  • Packet switched 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 PLMN’s, PSTN’s and ISDN’s.
  • Compatibility and interoperability of PLMN’s with different protocol versions and service facilities Addressing & Numbering.
  • Matters related to 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 Services.
  • Ensure the appropriate end-to-end network features for the support of services.
  • Call handling scenarios.


The Networks Group have face to face meetings and are held twice a year with conference calls used to progress work between physical meetings.

How to Get Involved

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

Alfonso Della Fera
Telecom Italia

Deputy Chair
Mark McGinley
AT&T Mobility

Javier Sendin

Roger Brown