BS EN 62439-3:2012

INTRODUCTION
1 Scope
2 Normative references
3 Terms, definitions, abbreviations, acronyms,
  and conventions
4 Parallel Redundancy Protocol (PRP)
5 High-availability Seamless Redundancy (HSR)
6 Protocol Implementation Conformance Statement
  (PICS)
7 PRP/HSR Management Information Base (MIB)
Annex A (informative) - PRP duplicate discard
        algorithm as pseudo-code
Bibliography
Annex ZA (normative) - Normative references to
         international publications with their
         corresponding European publications

Pertains to high-availability automation networks based on the ISO/IEC 8802-3 (IEEE 802.3) (Ethernet) technology.

IEC 62439-3:2012 specifies two redundancy protocols designed to provide seamless recovery in case of single failure of an inter-bridge link or bridge in the network, which are based on the same scheme: duplication of the LAN, resp. duplication of the transmitted information. This second edition cancels and replaces the first edition published in 2010. It constitutes a technical revision. The main changes with respect to the previous edition are:
- specification of the interconnection of PRP and HSR networks;
- introduction of a suffix for PRP frames;
- clarification and modification of specifications to ensure interoperability;
- slackening of the specifications to allow different implementations;
- consideration of clock synchronization according to IEC 61588;
- introduction of test modes to simplify testing and maintenance.

This publication is to be read in conjunction with IEC 62439-1:2010.