Improving TSN Simulation Accuracy in OMNeT++: A Hardware-Aligned Approach

Time-Sensitive Networking (TSN) encompasses standards to facilitate near-deterministic performance in wired networks and the integration of TSN with modern wireless systems, such as Fifth Generation (5G) systems, is intensely pursued. Consequently, TSN is examined by numerous research groups. Given the limited and costly access to TSN hardware, a reliable simulator becomes crucial. OMNeT++ is a modular simulator that can be expanded with network simulation models, such as INET, which can simulate TSN functionalities. We evaluate the accuracy of the OMNeT++ INET simulator in mirroring the physical (hardware-based) reality by comparing OMNeT++ INET simulations with measurements of two commercial TSN switches. Our evaluations encompass the generalized Precision Time Protocol (gPTP) accuracy, the Store-and-Forward (SF) and Cut-Through (CT) switching forwarding latencies, the Time Aware Shaper (TAS), and Frame Preemption (FP), including combinations of CT, TAS, and FP. We find that compared to hardware measurements, INET simulations exhibit different clock synchronization dynamics, underestimate the switching latencies, and do not support CT with FP. We enhance the alignment of INET simulations with authentic hardware behaviors by modifying INET modules. We modify the INET gPTP synchronization model and the INET simulation models for the SF and CT forwarding latencies. Also, we modify the INET simulation modules to support the combined operation of CT and FP. We demonstrate how our INET modifications, which we make publicly available, accurately simulate the behaviors of real TSN hardware.