Design and Implementation of a Containerized 5G Network Simulation Environment

Abstract:This technical report details the design and implementation of a carrier-grade 5G network testbed on a single Linux host using Linux Network Namespaces. A critical deficiency in standard "localhost" simulations (using Open5GS and UERANSIM) is "Traffic Leakage," where user-plane traffic inadvertently bypasses the GTP-U tunnel via the host's underlay network. We propose a robust "Hub and Spoke" architecture that strictly isolates the Radio Access Network (RAN) and Mobile Edge Computing (MEC) nodes into distinct virtual environments. Furthermore, we introduce a novel Routing Optimization Strategy that enforces strict separation between Overlay (5G Tunnel) and Underlay (Transport) traffic. This ensures that 100% of user data traverses the 5G Core, verified via packet capture analysis. The system supports Network Slicing with dedicated subnets for eMBB (SST: 1) and URLLC (SST: 2). Key Contributions:- Namespace Architecture: Implementation of a virtual topology isolating RAN and MEC nodes to mimic physical separation.- Kernel Correctness: Resolution of the "Checksum Offloading Bug" by forcing traffic over veth pairs to ensure valid GTP-U encapsulation.- Routing Isolation: Restoration of correct routing behavior for complex 5G topologies on a single machine, preventing split-tunneling leakage.