ML-SLD: A message-level stateless design for cloud-native 5G core network

The Internet of Things (IoTs) has become an essential component of the 5th Generation (5G) network and beyond, accelerating the transition to digital society. The increasing signaling traffic generated by billions of IoT devices has placed significant strain on the 5G Core network (5GC) control plane. To address this issue, the 3rd Generation Partnership Project (3GPP) first proposed a Service-Based Architecture (SBA), intending to create a flexible, scalable, and agile cloud-native 5GC. However, considering the coupling of protocol states and functions, there are still many challenges to fully utilize the benefits of the cloud computing and orchestrate the 5GC in a cloudnative manner. We propose a Message-Level StateLess Design (ML-SLD) to provide a cloud-native 5GC from an architectural standpoint in this paper. Firstly, we propose an innovative mechanism for servitization of the N2 interface to maintain the connection between Radio Access Network (RAN) and the 5GC, avoiding interruptions and dropouts of large-scale user data. Furthermore, we propose an On-demand Message Forwarding (OMF) algorithm to reduce the impact of cloud fluctuations on the performance of cloud-native 5GC. Finally, we create a prototype that is based on the OpenAirInterface (OAI) 5G core network projects, with all Network Functions (NFs) packaged in dockers and deployed in a kubernetes-based cloud environment. Several experiments have been built with UERANSIM and Chaosblade simulation tools. The findings demonstrate the viability and efficiency of our proposed methods.