I. Introduction
Digital Twin (DT) is expected to save manuscription cost, shorten research and development (R&D) cycle, and reduce optimization and maintenance complexity. Digital Twin Network (DTN) indicates the DT of telecommunication network. ITU-T Y.3090 specified DTN definition as "Digital twin network is a virtual representation of the physical network. It is useful for analyzing, diagnosing, simulating and controlling the physical network based on data, model and interface, so as to achieve the real-time interactive mapping between physical network and virtual twin network." [1]. DTN is hoped to assist Network Life Cycle (NLC) all stages including planning, implementing, maintaining, optimizing, and operating.