IEEE 802.1CB Frame Elimination in a Wireless HSR Architecture

Abstract

High reliability wireless communications for mission-critical applications often necessitates path diversity through redundant channels. In this context, we explore the combination of the IEC 62439 High-availability Seamless Redundancy (HSR) architecture with IEEE 802.1CB Frame Replication and Elimination for Reliability (FRER) features. While HSR is well-established for wired networks, both HSR and FRER aim to enhance network reliability through redundancy. However, the HSR algorithm assumes frame ordering, which is impractical in wireless networks due to packet ordering and time-based elimination challenges. To address this, we propose integrating the IEEE 802.1CB vector recovery algorithm within the HSR framework. We focus on Wireless Local Area Networks (WLANs), where we modify an existing HSR implementation in Linux to operate over wireless channels. Our experimental analysis demonstrates significant improvements in latency metrics compared to non-redundant communications subject to interfering traffic. The proposed implementation targets industrial applications, such as robotic feedback control with stringent two-millisecond latency deadlines. By considering latency and out-of-order delivery—features not well-supported by the current HSR standard, we demonstrate improved reliability and latency characteristics required for demanding real-time control applications utilizing wireless as a principal communications medium.