IEC 62439-3:2009 specifies two redundancy protocols based on the duplication of the LAN, resp. duplication of the transmitted information, designed to provide seamless recovery in case of single failure of an inter-switch link or switch in the network. This standard cancels and replaces IEC 62439 published in 2008. This first edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 62439 (2008):
- adding a calculation method for RSTP (rapid spanning tree protocol, IEEE 802.1Q),
- adding two new redundancy protocols: HSR (High-availability Seamless Redundancy) and DRP (Distributed Redundancy Protocol),
- moving former Clauses 1 to 4 (introduction, definitions, general aspects) and the Annexes (taxonomy, availability calculation) to IEC 62439-1, which serves now as a base for the other documents,
- moving Clause 5 (MRP) to IEC 62439-2 with minor editorial changes,
- moving Clause 6 (PRP) to IEC 62439-3 with minor editorial changes,
- moving Clause 7 (CRP) to IEC 62439-4 with minor editorial changes, and
- moving Clause 8 (BRP) to IEC 62439-5 with minor editorial changes,
- adding a method to calculate the maximum recovery time of RSTP in a restricted configuration (ring) to IEC 62439-1 as Clause 8,
- adding specifications of the HSR (High-availability Seamless Redundancy) protocol, which shares the principles of PRP to IEC 62439-3 as Clause 5, and
- introducing the DRP protocol as IEC 62439-6. This bilingual version (2016-07) corresponds to the English version, published in 2012-07.