Sharding the Datastore Network Functions of 5G Core for Scalable and Resilient Slice Service

The continuously growing demand for availing services on 5G has resulted in a massive amount of user data being stored and tracked at the 5G Core (5GC). Also, the amount of traffic arriving in the control plane demands a scalable yet highly available design of the datastore in the 5GC. This paper introduces a novel approach addressing these challenges by integrating the database sharding and replica set techniques into the Unified Data Management (UDM) and Unstructured Data Storage Function (UDSF) of 5GC. Sharding is employed to efficiently distribute and manage extensive user data, ensuring not only scalability but also resilience, and High Availability (HA). Specifically, we propose range-based and slice-specific sharding techniques, each tailored to meet specific service and slice requirements. Through a comparative analysis of these sharding methods on the 3GPP-compliant 5G testbed, the paper illuminates their distinct advantages and limitations. While the range-based sharding shows a significant improvement in UE registration completion time of approximately 29.13%, slicespecific sharding demonstrates an even higher average benefit of about 31.46%. We hope that the insights presented in this paper are quite promising in enhancing 5G infrastructure to facilitate a variety of 5G services and elevated end-user experience.