PRP topology presented here is a reference system for process bus usage with proper switches supporting IEEE 1588 v2. This topology includes duplicated star networks which are in PRP called LAN A and LAN B. IEEE 1588 v2 clock masters are connected to the network utilizing Ethernet switches. Ethernet switches filter out IEC 61850-9-2 LE traffic from the IEEE 1588 v2 clock masters. PRP LAN A is presented with dark blue lines and LAN B with light blue.
It is important in PRP not to connect LAN A and LAN B anywhere else than to end devices supporting PRP. Otherwise Ethernet communication is disturbed and might not work. All devices connected to both LAN A and LAN B must support the PRP protocol. Single attached nodes can be connected directly to LAN A or LAN B in which case there is no redundancy for this node or with a separate redundancy box (RedBox).