IEEE 802.1Qch, also known as cyclic queuing and forwarding (CQF) shaper, enhanced the dynamic and flexible behavior of time-sensitive networking. Schedulability of the CQF is one of the major research fields used to improve system performance. Existing CQF heuristic scheduling approaches only consider the relative deadline in stream sorting or the link utilization in route selection, which encounters limitations while striving to attain high schedulability of streams. We propose an efficient scheduling for CQF. The main contributions are: We provide the earliest virtual absolute deadline first policy, which prioritizes stream instances based on their earliest absolute deadlines, intending to prior allocate resources to the stream instance with the greatest “urgency.” To provide a deep insight into efficient route selection, we then introduce a quality-of-service-aware indicator of a route that mainly accounts for slot utilization and route length, which enables us to select a route with a balance of slot utilization and shorter route length for a stream instance. With the comprehensive evaluation, our method achieves an average schedulability improvement of 31.73%, 17.93%, and 31.85% compared with state-of-the-art methods. Furthermore, our approach can be extended to other CQF-related shapers or time-division scheduling scenarios, significantly enhancing stream schedulability.

Time-Sensitive Networking (TSN) has become the most popular technique in modern safety-critical Automotive and Industrial Automation Networks by providing deterministic transmission policies. However, the data of TSN messages may be affected by transient faults. IEEE 802.1CB, a reliability standard in TSN, protects against such faults by providing disjoint redundant routes for each stream. However, the unique assumption may present a new challenge, i.e., an inadequate number of redundant routes that may negatively impact stream scheduling. This paper presents an offline fault-tolerant TSN scheduling approach that considers such impacts for real-time streams (such as Time-Trigger (TT) and Audio Video Bridging (AVB) streams). Specifically, we intend to calculate the minimum upper bound number of disjoint routes required for each stream to meet the reliability requirements, subsequently enhancing the network’s schedulability. We also propose a service degradation function for AVB streams when the network is under heavy load caused by redundant transmissions of TT streams. This function will maintain schedulability and reliability for AVB streams. Experiments with small-and large-scale synthetic networks show the efficiency.