Siemens SCALANCE W1780 Configuration Manual page 45

How it works
A PRP network consists of two completely independent networks. If one network is disrupted,
the frames are sent without interruption/reconfiguration via the parallel redundant network. To
achieve this the Ethernet frames are sent to the recipient in duplicate via both networks.
Devices capable of PRP have at least two separate Ethernet interfaces that are connected to
independent networks.
With devices not capable of PRP a redundancy box (RedBox) is connected upstream. This
allows access for so-called Single Attached Nodes (SAN) to PRP networks. The RedBox
duplicates every Ethernet frame to be sent and adds a PRP trailer to the frame that among other
things contains a sequence number. The RedBox simultaneously sends a copy of the frame to
the PRP A and PRP B network. At the receiving end the duplicate frame is discarded by the
RedBox. For this the RedBox requires certain transfer times designed for Ethernet networks.
For this reason using PRP in WLAN networks results in duplicate and delayed frames.
With iPRP, this problem is solved and the use of PRP in WLAN with SCALANCE W devices
becomes possible
SCALANCE W1780/W1740 according to IEEE 802.11ac Web Based Management
Configuration Manual, 11/2019, C79000-G8976-C485-03
Technical basics
4.9 iFeatures
45