Reliability Analysis of the Proactive Transmission of Replicated Frames Mechanism over Time-Sensitive Networking

The Time-Sensitive Networking (TSN) Task Group has standardised different mechanisms to provide Ethernet with hard real-time guarantees and reliability in layer 2 of the network architecture. Specifically, TSN proposes using space redundancy to increase the reliability of Ethernet networks, but using space redundancy to tolerate temporary faults is not a cost-effective solution. For this reason, we propose to use time redundancy to tolerate temporary faults in the links of TSN-based networks. Specifically, in previous works we proposed the Proactive Transmission of Replicated Frames (PTRF) mechanism to tolerate temporary faults in the links. Now, in this work we present a series of models of TSN and PTRF developed using PRISM, a probabilistic model checker that can be used to evaluate the reliability of systems. After that, we carry out a parametric sensitivity analysis of the reliability achievable by TSN and PTRF and we show that we can increase the reliability of TSN-based networks using PTRF to tolerate temporary faults in the links of TSN networks. This is the first work that presents a quantitative analysis of the reliability of TSN networks.

Area-Efficient Differential Fault Tolerance Encoding for Finite State Machines

A differential fault tolerance encoding is presented for finite state machines (FSMs) to improve their area efficiency. As the manufacturing technology for semiconductors continues to scale down, the probability of the occurrence of unexpected faults in integrated circuits has been increasing. Because an FSM controls an entire digital circuit, the faults in FSMs should be carefully addressed. Whereas the previous encoding applies a fault tolerance scheme to all the states in an FSM, the proposed encoding applies a fault tolerance scheme to only specific states depending on their importance. Compared with the previous complete fault tolerance encoding, the proposed encoding provides a comparable failure probability with a small hardware by applying the fault tolerance scheme differently to each state. The proposed method improves the area efficiency by 36.1%, 43.8%, 49.2%, and 74.6% compared with that by the non-fault tolerance, previous hardware redundancy, information redundancy, and time redundancy methods, respectively. Consequently, the proposed method can provide a flexible solution by applying the fault tolerance differently depending on the importance of the states.