Abstract: Next-generation Network Centric Warfare (NCW) [1] foresees naval platforms running unified Internet Protocol (IP) networks capable of running different applications on the same backbone. To promote this NCW concept, Thales Australia has proposed a digital ship local area network (LAN) architecture called the Ship Unified Network IP for Communications Ship (SUNI/CS). A small-scale prototype of this SUNI/CS network has been constructed in Thales Australia's Network Enabled Warfare Laboratory (NEWLab). To mitigate the technical risks of a large-scale deployable digital ship LAN, the network performance and capacity needs to be understood before deployment. Clearly it is impractical to build a full-scale digital ship LAN in a laboratory environment. To overcome this, modelling and simulation of network performance using a discrete event simulator such as OPNET is required. As the first step in modelling a large-scale deployable digital ship LAN, a benchmark study has been conducted to validate the OPNET models against real-life measurements on the SUNI/CS network. In this study, packet delay and throughput were simulated in OPNET and measured on SUNI/CS. A comparison of these results showed the simulated OPNET model accurately matched the measured SUNI/CS results. This study paved the way for future efforts in network capacity and performance measurement on a real-scale digital ship LAN OPNET model.