State Management Function Placement for Service-Based 5G Mobile Core Architecture

摘要

Service-based 5G core architecture is designed to take advantages of network function virtualization and software-defined networking. In addition to the control and data plane separation, the service-based 5G core decouples the computing and storage resources which separates the mobile functions into two categories: "stateless" control functions and state management functions. Such new features improve 5G core network in terms of independent scalability and fast failure recovery. In geo-distributed cloud infrastructure-based 5G core networks, the "stateless" control functions can be deployed to all cloud centers close to access networks to reduce latency and traffic load burden. However, we can not deploy state management functions to all cloud centers which results in the high state transfer cost. In addition, we can not use only one state management function for entire network which results in high traffic load burden. Therefore, the placement of state management functions involves different conflicting design objectives which requires a new model to optimally place these functions. In this paper, we propose a multi-objective model which can achieve the balance between state transfer cost and traffic load burden on state management functions. We first solve our model using epsilon - constraint approach which tries to optimize one objective while keeping another under threshold. Second, we propose an adaptive solution based on adaptive weighted sum approach to find a set of Pareto optimal solutions for our multi-objective model. Simulation results show that our proposed solution offers better balance between two design objectives compared to other solutions.