HSR (High-availability Seamless Redundancy) is a fault-tolerant Ethernet protocol specified in IEC 62439-3, designed for applications where continuous data transmission is critical. It operates using a ring or mesh topology, where each node simultaneously sends duplicate Ethernet frames in both directions. This ensures that even if one link fails, the other path still delivers the data with zero recovery time, making HSR highly suitable for real-time, mission-critical systems such as substation automation, industrial control, and transportation.
A key difference between HSR and PRP (Parallel Redundancy Protocol) lies in their network topology and implementation approach:
HSR uses a single network infrastructure with a ring or mesh configuration, allowing for compact or space-constrained installations without the need for separate switches or links. Each device must be HSR-capable and interconnected in the ring.
PRP, by contrast, requires two completely separate LANs (LAN A and LAN B), with each device transmitting duplicate frames over both networks.
Only few devices like the DTS 4163.grandmaster support both HSR and PRP protocols as defined in IEC 62439-3. This allows the device to be used in a range of redundant network configurations, including HSR ring topologies, PRP dual-network setups, and in some cases, hybrid environments.
