Networks Group (GSMA Working Group)

Description

The Networks Group (NG) is a permanent working group within the GSM Association (GSMA), the industry organization that represents mobile network operators worldwide. Unlike 3GPP, which defines the technical radio and core network standards, the GSMA's NG focuses on the commercial and operational aspects of implementing these technologies to ensure seamless interoperability between different operators' networks on a global scale. Its work is critical for services that traverse operator boundaries, such as voice and SMS interconnection, mobile roaming, and number portability.

The NG operates through a structure of sub-working groups and teams, each tackling specific areas. Key areas of responsibility include defining the technical requirements and implementation guidelines for inter-operator interfaces, especially those related to signaling and data exchange. A prime example is the work on the IP eXchange (IPX) network, a private, multi-service IP backbone defined by GSMA for interconnecting operators and service providers. The NG defines the service level agreements (SLAs), quality of service (QoS) classes, and technical specifications for services delivered over IPX, such as voice over LTE (VoLTE) and SMS over IP (SMSoIP) roaming.

Another major function of the NG is the development and maintenance of key roaming documents and specifications. This includes the IR.21 ("GSM Association Roaming Database, Structure and Updating Procedures") document, which standardizes the format for operators to publish their network and roaming capabilities, and the IR.88 ("LTE and EPC Roaming Guidelines") which provides detailed technical guidelines for LTE roaming architecture (S8HR, LBO). The group also works on the specifications for steering of roaming (SoR) and the interoperability of network functions like the Security Gateway (SEG) for N32 interface in 5G roaming.

The NG's role extends into the 5G era, where it addresses new complexities. It works on defining the inter-operator standards for 5G standalone (SA) roaming, including the security framework for the interconnection between network functions (like SEPP) and the guidelines for supporting network slicing in a roaming environment. By providing these implementation blueprints, the NG ensures that the theoretical capabilities defined by 3GPP can be practically and consistently deployed by hundreds of operators globally, preventing fragmentation and enabling a unified user experience for services like international 5G data roaming and voice over New Radio (VoNR).

Purpose & Motivation

The NG exists to solve the practical, real-world problem of interoperability between independent, competitive mobile network operators. While 3GPP creates the technology standards, the GSMA NG provides the essential commercial and operational glue that allows these technologies to work across network borders. Its work is motivated by the need for a consistent, reliable, and efficient global mobile ecosystem.

Historically, as GSM expanded globally, ad-hoc bilateral agreements for roaming and interconnection led to complexity, high costs, and inconsistent service quality. The NG was formed to create common standards and best practices, reducing the cost and time required for operators to establish interoperable services. It addresses limitations of purely technical standards by specifying the "how" of implementation, including testing requirements, billing exchange procedures, and fault management processes between operators.

In the context of evolving technologies like 4G LTE and 5G, the NG's purpose becomes even more critical. New architectures like IP-based core networks (EPC, 5GC) and complex features like network slicing introduce new interconnection challenges. The NG provides the forum for operators to agree on common deployment models, security frameworks, and quality benchmarks, ensuring that innovation in the standards translates smoothly into interoperable commercial services without creating new silos or barriers to global connectivity.

Key Features

• Defines technical and operational standards for inter-operator services
• Develops and maintains key roaming documentation (e.g., IR.21, IR.88)
• Specifies guidelines for IPX network services and QoS
• Addresses interoperability for VoLTE, SMS over IP, and 5G roaming
• Provides implementation blueprints for 3GPP features in multi-operator scenarios
• Focuses on commercial and operational aspects beyond pure protocol specification

Evolution Across Releases

Defining Specifications