In safety-critical domains such as avionics and industrial automation, the transmission of network traffic may be affected by transient failures that result in data errors. Time-Sensitive Networking (TSN) enhances traffic reliability through mechanisms like Frame Replication and Elimination for Reliability (FRER), which enables traffic to be multipath through the network by providing link redundancy. However, FRER does not provide a method for assessing reliability and redundant routing. In existing reliability assessment studies of traffic, the assumptions of redundant paths are based on combinations of multiple disjoint end-to-end paths, which is not universal considering the diversity of network topologies and the flexibility of redundant routing. Furthermore, reliability is not only related to redundant routing, real-time performance also plays a crucial role since its delay at nodes and links will directly affect failure probability. Most of the previous works focus on time-triggered (TT) flows, whose real-time results can be obtained directly through a predefined time window, while audio video bridging (AVB) flows need to be introduced into real-time analysis method to realize overall assessment of reliability. In this regard, first, this paper proposes a generalized TSN transient failure reliability assessment method, which can be used for arbitrary redundant routes to give generalized reliability assessment results. Then, we introduce a Network Calculus based model to analyze the AVB flow's real-time performance and its impact on reliability. On this basis, we also propose a redundant routing method for flows and conduct an example analysis, and the results prove that the method can guarantee the reliability of traffic under a variety of network topologies, demonstrating its effectiveness and applicability.