Red Box (Redunancy Box)

A Red Box (short for Redundancy Box) is a device used in PRP (Parallel Redundancy Protocol) and HSR (High-availability Seamless Redundancy) networks to enable redundant communication for nodes that do not natively support these protocols. Red Boxes act as gateways, allowing single-attached nodes (SANs) to participate in a redundant network by duplicating outgoing frames and filtering incoming ones from parallel network paths.

While Red Boxes ensure compatibility with legacy or standard Ethernet devices, they also introduce additional complexity, cost, and potential latency into the network. As more modern devices like the DTS 4163.grandmaster offer native PRP/HSR support, the use of Red Boxes is declining in favor of integrated redundancy solutions.