Ring Node States

There are three different states for each node of a specific ring:

init—Not a participant of a specific ring.
idle—No failure on the ring, the node is performing normally. For normal node, traffic is unblocked on both ring ports. For the RPL owner, traffic is blocked on the ring port that connects to the RPL and unblocked on the other ring port.
protection—A failure occurred on the ring. For normal node, traffic is blocked on the ring port that connects to the failing link and unblocked on working ring ports. For the RPL owner, traffic is unblocked on both ring ports if they connect to non-failure links.

There can only one RPL owner for each ring. The user configuration must guarantee this, because the APS protocol cannot check this.