(default) Additions to IEEE Std 1588 All clocks can be doubly attached using the IEC 62439-3 protocol (PRP "Parallel Redundancy Protocol" or HSR "High-availability Seamless Redundancy"). Several master clocks can be active at the same time; the slave selects the best master. Time-outs ensure that the clocks can detect the loss of PTP messages also on the unused path. Identification of the peer node to check the topology of the network and ensure that all elements support the protocol. In network using store-and-forward media converters, the master appends a padding to Sync messages to ensure that Sync and Pdelay_Req/Pdelay_Resp messages have the same size (this will specified in IEEE 1588:2017) Network management by SNMP according to IEC 62439-3 Annex E or by IEC 61850 consider the extension Local time distribution For applications that do not use the corresponding function in IEC 61850, the grandmaster may distribute local time (e.g. for human display) using the ALTERNATE_TIME_OFFSET_INDICATOR TLV as specified in IEEE Std 1588 §16.3. Standard owners This protocol has been developed 2012-2014 by the IEC SC65C WG15 in the framework of IEC 62439-3, which applies to all IEC industrial networks, as PTP profile L2P2P (Layer2, peer-to-peer). To avoid parallel standards in IEC and IEEE in the field of grid automation, this work has been placed under the umbrella of the IEC&IEEE Joint Development 61850-9-3. Technical responsibility rests with IEC SC65C WG15, which is committed to keep the IEC 62439-3 profile L2P2P and IEC/IEEE 61850-9-3 aligned. References External links IEC 61588:2009 Precision clock synchronization protocol for networked measurement and control systems IEC/IEEE 61850-9-3, Communication networks and systems for power utility automation – Part 9-3: Precision time protocol profile for power utility automation IEC TR 61850-90-4:2013 Communication networks and systems for power utility automation - Part 90-4: Network engineering guidelines Tutorial on HSR Tutorial on Parallel Redundancy Protocol (PRP) Tutorial on the fault-tolerant precision time protocol profiles in IEC 62439-3 IEC 62439-3 Tissues (Technical issues) database for IEC 62439-3 IEC 61850-9-3 Tissues (Technical issues) database for IEC/IEEE 61850-9-3 Networking standards Network protocols