Overview
IEC 62439-3:2016 - Industrial communication networks - High availability automation networks - Part 3: Parallel Redundancy Protocol (PRP) and High-availability Seamless Redundancy (HSR) - defines two Ethernet-based redundancy protocols that deliver seamless recovery from single network or bridge/link failures by using parallel transmission of duplicated information. Edition 3.0 (2016) is a technical revision of the 2012 edition and adds technical corrections, extended specifications, and explicit consideration of IEC 61588 (PTP) clock synchronization using end-to-end delay measurement alongside peer-to-peer delay measurement in PRP.
Key Topics and Requirements
- PRP (Parallel Redundancy Protocol): topology options, doubly attached node structures (DANP), duplicate handling, PRP_Supervision frames, unicast/multicast addressing and service specification, and guidance for installation, configuration and repair.
- HSR (High-availability Seamless Redundancy): ring-based operation, DANH node and RedBox/QuadBox definitions, forwarding rules, HSR frame format, supervision, and deterministic medium access considerations.
- Clock synchronization: normative mapping and guidance for using PTP (IEC 61588 / IEEE C37.238) over redundant paths, including annexes on redundant clock attachment and PTP profiles for high-availability automation.
- Management and conformance: Protocol Implementation Conformance Statement (PICS), PRP/HSR MIB, supervision and redundancy management interfaces.
- Annexes: detailed normative annexes on PTP mapping, redundant clock models, and profiles for power-utility and automation applications; informative PTP tutorial.
Applications and Who Uses It
IEC 62439-3 is targeted at systems that require uninterrupted Ethernet communications and deterministic behavior in the face of single failures. Typical applications include:
- Power utility and substation automation
- Process control and manufacturing automation
- Railway signaling and transportation control
- Critical infrastructures requiring zero packet-loss on failure
Primary users:
- Network architects and automation engineers designing high-availability Ethernet networks
- System integrators and OEMs implementing PRP/HSR-capable devices
- Vendors creating switches, RedBoxes, and HSR/PRP endpoints
- Test labs and certification bodies verifying conformance (PICS, MIBs)
Related Standards
- IEC 61588 (Precision Time Protocol - PTP): referenced for clock synchronization over redundant paths.
- IEEE C37.238: relevant for PTP in power systems and referenced in mapping annexes.
- Other parts of the IEC 62439 series (for context on high-availability automation networks and implementation guidance).
Keywords: IEC 62439-3, PRP, HSR, high-availability automation networks, seamless redundancy, Parallel Redundancy Protocol, High-availability Seamless Redundancy, Ethernet redundancy, IEC 61588, PTP.