Patent ID: 8582424

Claim:
A ring coupling node comprising: first and second ring communication ports connected to first and second neighbor nodes, respectively, of a communication ring; and a third non-ring communication port, the ring-coupling node storing program code that causes the ring-coupling node to execute the steps of: receiving from a source device, via the third non-ring communication port, a source frame addressed to a destination node in the communication ring; storing an identification of the source device; generating two ring frames that contain the same information as the source frame; transmitting, via the first and the second ring communication ports, respectively, the two ring frames to the first and second neighbor nodes; forwarding to the third non-ring communication port an earlier frame of a pair of ring frames addressed to a destination device connected to the third non-ring communication port and received from a source node in the communication ring via the first and the second ring communication port, respectively; rejecting a later frame of the pair; generating, based on a ring redundancy identifier included in the earlier ring frame, a destination redundancy identifier associated with the destination device; and replacing in the forwarded ring frame, the ring redundancy identifier with the destination redundancy identifier; and generating a destination redundancy identifier based on the IEC 62439 (PRP) standard in case the destination device and the coupling node are connected to the same PRP LAN (A, B), or in case the ring frame is a multicast frame to be received by a non-PRP device.