FOS: A Shaping Mechanism for Frame Ordering in Time Sensitive Networking

Time Sensitive Networking (TSN) is a recently proposed technology claiming to be capable of transmitting both best effort and real-time traffic simultaneously. TSN achieves real-time communications by per-queue Time-Division Multiplexing and takes no notice of the details of incoming frames. Therefore, the forwarding in TSN suffers from packet reordering because the practical forward sequences may differ from the window schedules, i.e., frame disordering errors. To enhance the robustness of TSN, in this paper, we propose a shaping mechanism, FOS, for frame ordering. FOS is able to sort incoming frames into expected sequences, therefore, providing the capacity of frame ordering configuration. To evaluate its performance, we conduct simulations for FOS based on a complete switch model under various conditions. The results prove the functional correctness of FOS and demonstrate that the FOS residence time is 15% to 34% of the total residence time. Therefore, FOS is able to guarantee the frame sequences without requiring unreasonable extra time.