CoreESIM: 5G Roaming Implications for SA vs NSA Architectures
3 min read
CoreESIM plays a pivotal role in enabling seamless global connectivity for subscribers, particularly as mobile network operators (MNOs) transition to 5G. For roamers, the distinction between 5G Non-Standalone (NSA) and Standalone (SA) architectures presents unique technical and operational considerations that directly impact service delivery and CoreESIM profile management.
5G NSA deployments leverage the existing 4G LTE Evolved Packet Core (EPC) for control plane functions and mobility management, while utilizing 5G New Radio (NR) for enhanced radio access. For roamers, this architecture generally maintains established roaming interfaces, primarily S8-HR or S8-LR for data plane traffic, and LBO where applicable. CoreESIM facilitates the provisioning of subscriber profiles compatible with these EPC-anchored scenarios, ensuring continuity of service without significant overhauls to existing roaming agreements or core network elements. This simplifies initial 5G roaming rollouts by building upon mature 4G roaming frameworks, as defined by GSMA IR.88 and 3GPP TS.23.401.
5G SA vs NSA Roaming Protocols
The advent of 5G SA introduces a new 5G Core (5GC) based on a service-based architecture (SBA), as specified in 3GPP TS.23.501 and TS.23.502. For roamers, this necessitates new roaming interfaces and protocols. The Security Edge Protection Proxy (SEPP) and N32 interface become critical for secure inter-PLMN communication, while the Network Repository Function (NRF) facilitates service discovery. SA roaming enables the full suite of 5G capabilities, including ultra-low latency and network slicing, not fully realized in NSA. CoreESIM's capability to manage and provision profiles conforming to these advanced 5GC roaming paradigms, ensuring proper subscription authentication and authorization across diverse MNO infrastructures, is paramount. This includes supporting updated local breakout options within the 5GC framework.
CoreESIM's functionality extends to securely managing the lifecycle of these 5G roaming profiles, from initial provisioning to updates and deactivation. Adherence to GSMA SGP.22 and SGP.02 is fundamental, ensuring integrity and confidentiality of subscriber credentials. CoreESIM platforms must dynamically assign and activate profiles that align with the roaming agreement capabilities of the visited network (5G NSA, 5G SA, or both) and the home network's policies. This includes managing PRPLMN lists and ensuring seamless handover, optimizing user experience while adhering to charging principles outlined in GSMA IR.21 and IR.65.
Key considerations for MNOs include the complexity of implementing N32 interfaces and updating billing and charging systems for 5GC services. CoreESIM provides the essential underlying infrastructure to abstract much of this complexity from the end-user, ensuring that a roamer's device can connect to the best available 5G service, regardless of the underlying SA or NSA architecture, through robust profile management and secure credential handling.