Roaming Exchange Network Data Analytics Function

Description

The Roaming Exchange Network Data Analytics Function (RE-NWDAF) is a deployment variant of the standard 3GPP NWDAF, tailored for the roaming exchange environment. An NWDAF is a 5G core network function defined for data collection and analytics. The RE-NWDAF is specifically instantiated within the infrastructure of a roaming exchange provider (also known as a Data Clearing House or IPX provider), which sits between the home Public Land Mobile Network (HPLMN) and the visited PLMN (VPLMN). Its primary role is to gain a holistic, cross-operator view of roaming traffic and performance, which is not visible to any single operator's NWDAF.

Architecturally, the RE-NWDAF interfaces with various network functions and data sources across the roaming ecosystem. This includes collecting data from the roaming exchange's own systems (e.g., signaling transfer points for Diameter and HTTP/2), as well as potentially subscribing to analytics events from NWDAFs in the HPLMN and VPLMN (via the Nnwdaf_EventsMonitoring service). It can ingest a wide array of data types: signaling messages (e.g., Nudm, Npcf, Namf), user plane events, policy control events, and performance measurements related to roaming sessions.

The RE-NWDAF applies machine learning (ML) models and analytics logic to this federated data set. It works by correlating events from both the home and visited network perspectives for the same subscriber session. This allows it to generate unique insights, such as end-to-end quality of experience (QoE) for a roaming user, identification of anomalies or fraud patterns that span multiple networks (e.g., simultaneous registration attacks), and analytics on roaming traffic trends and hotspots. It can provide its analytics outputs to the roaming exchange's own operational systems, or expose them as a service to subscribing network operators via standardized interfaces, helping them optimize roaming agreements and troubleshoot cross-border service issues.

Purpose & Motivation

The RE-NWDAF was introduced to address the specific data analytics challenges in the global roaming ecosystem. In 5G standalone roaming, the home and visited networks have limited visibility into each other's domains. A home operator's NWDAF sees only the home network control plane and aggregated reports, while the visited network's NWDAF sees only its local context. This creates a blind spot for end-to-end service assurance, fraud management, and optimization of the roaming experience.

Traditional roaming analytics relied on offline processing of billing records (TAP files) or signaling data from a single network's perspective, which was slow and incomplete. The motivation for RE-NWDAF stems from the need for real-time, cross-operator intelligence to support advanced 5G roaming services, network slicing across borders, and stringent service level agreements (SLAs). By leveraging the roaming exchange's unique position as a hub for inter-operator traffic, the RE-NWDAF can synthesize a complete picture. It solves problems like diagnosing the root cause of a roaming session drop (was it in the HPLMN, VPLMN, or the interconnect?), detecting sophisticated fraud that exploits jurisdictional gaps, and providing data-driven insights for negotiating and monitoring roaming partnerships.