An Efficient Pro-Active Fault-Tolerance Scheduling of IEEE 802.1Qbv Time-Sensitive Network

Time-sensitive network (TSN) has emerged as one of the enhancement Ethernet technologies of real-time applications for future industrial networks. However, the data of TSN messages may be unexpectedly changed within the transmission duration due to electromagnetic interference. A cyclic redundancy check (CRC) can detect such errors and notify the sender node to retransmit the erroneous message through automatic repeat request (ARQ). The time when the error occurs is uncertain. Consequently, the time when performing the retransmission requests is also random, which results in different transmission sequences and violates the deterministic transmission of TSN. In addition, the returned CRC detection messages also might be at fault during transmission. In order to provide the fault tolerance capability of critical flows in TSN without violating the nature of deterministic transmission, this article proposes a pro-active fault-tolerant TSN scheduling algorithm (PFT-TSN), which not only transmits a certain number of instance copies for critical flows but provides network transmission services for noncritical flows. The challenge is that schedulability and safety of critical flows are tradeoffs in terms of the number of transmissions per instance of critical flows and the schedulability. Moreover, the transmission service of noncritical flows can also affect the schedulability of critical flows. We conduct comprehensive experiments with synthetic networks to show that the proposed method can meet both safety and schedulability requirements for critical flows, and noncritical flows are also allowed to be transmitted by the service degradation.