"Federated XR-Network Digital Twins: Enabling Real-Time Collaboration in future 6G Environments"

"Network Digital Twins (NDTs) provide a real-time digital representation of an Original Network (ON), enabling monitoring, life-cycle automation, optimization, flexibility, and scalability, among other benefits in Beyond 5G (B5G) and 6G networks. NDTs are typically established through a one-to-one (1:1) model in which a unique NDT replica is derived from an ON. The main limitation of current NDT systems lies in the inability of such systems to support concurrent and isolated real-time operation among multiple tenants. This limitation constitutes a constraint in the deployment of real-time collaborative scenarios where multiple users require simultaneous access to a customized instantiated network. To address the concurrent access of NDTs, this article presents an extended NDT model, designated as one-to-many (1:N), in which multiple NDTs are derived from a single ON and coordinated leveraging an NDT federation framework. Federation mechanisms are supported by a centralized entity known as the Digital Twin Manager (DTM). The DTM enables coordination, synchronization, isolation, and consistency across multiple NDT instances. The 1:N NDT architecture is technology-agnostic. This article examines the role of extended reality (XR) in customizing each deployed NDT instance to facilitate immersive experiences to allow users to interact intuitively with digital environments. A Proof-of-Concept (PoC) implementation is introduced to evaluate the feasibility of a federated NDT system by analyzing the synchronization latency, dissemination overhead, and scalability trends under controlled conditions. The results of the study indicate predictable fan-out behavior and manageable coordination overhead. This supports the feasibility of federated NDT operation for collaborative network management scenarios in future networks."