How does PRP operate?
PRP devices act as the sender and receiver of PRP packets, whereby PRP devices are capable of assuming both roles.
The sender operates as follows:
- It duplicates packets to produce twin pakets, and sends them over 2 independent (W)LANs.
- Each packet is given a redundancy control trailer (RCT).
The RCT provides the following information for the recipient:
- It identifies the packet as a PRP packet.
- It contains a sequence ID.
- It shows which (W)LAN the packet arrived from.
- It contains the packet size.
The sequence ID is a consecutive incremented number. The sequence ID together with the the source MAC address allow the receiver to detect duplicate packets. Duplicate detection causes the packet arriving later to be discarded.
The receiver operates as follows:
- It reads the RCT.
- It forwards the first of the duplicated packets without its RCT.
- Through duplicate detection, the receiver discards the packet that arrives later.
