Enhancing Reliability of Scheduled Traffic in Time-Sensitive Networks using Frame Replication and Elimination

The IEEE 802.1CB standard for Frame Replication and Elimination for Reliability (FRER) emphasises improving reliability by introducing link redundancy. In this paper, two approaches towards the elimination of duplicates are implemented on a programmable pipelined switch. The first approach meets the intermittent stream traffic goal of the standard. A sliding window-based algorithm is used for storing and comparing identification numbers of packets. The second approach handles bulk stream traffic by using a hash table along with the sliding window for a faster lookup, making it more scalable. Hash-collision mitigation with the help of stream identification is also incorporated in the hash table approach. The algorithms are implemented in P4 and Micro-C. Latency versus window size obtained for both the approaches and the end-to-end packet loss reduction yielded by FRER in presence of lossy intermediate links are demonstrated.