Parallel Redundancy Protocol (PRP)
Parallel Redundancy Protocol (PRP) is defined in international standard IEC 62439-3 and provides high-availability in Ethernet networks. PRP technology creates seamless redundancy by sending duplicate frames to two independent network infrastructures, which are known as LAN A and LAN B.
A PRP network includes the following components.
Component | Description |
|---|---|
LAN A and LAN B | Redundant, active Ethernet networks that operate in parallel. |
Double attached node (DAN) | An end device with PRP technology that connects to both LAN A and LAN B. |
Single attached node (SAN) | An end device without PRP technology that connects to either LAN A or LAN B. A SAN does not have PRP redundancy. |
Redundancy box (RedBox) | A switch with PRP technology that connects devices without PRP technology to LAN A and LAN B. |
Virtual double attached node (VDAN) | An end device without PRP technology that connects to both LAN A and LAN B through a RedBox. A VDAN has PRP redundancy and appears to other nodes in the network as a DAN. |
Infrastructure switch | A switch that connects to either LAN A or LAN B and is not configured as a RedBox. |
For more information about PRP, see the EtherNet/IP Parallel Redundancy Protocol Application Technique, publication ENET-AT006.
Use PRP in a Redundancy System
For supported PRP I/O network topologies and design guidelines for high availability systems, see the High Availability Systems Reference Manual, HIGHAV-RM002.
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