27.2.4 Switching communication paths

(1) Transit Node Route Switching

When a ring fault is detected on the master node, a control frame called a flush control frame is sent to other transit nodes in the ring of the same control VLAN, to request that MAC address table entries be cleared. When this flush control frame is received, the transit node clears MAC address table entry. Because of this, flooding occurs until MAC address learning is performed. MAC address learning is performed by sending and receiving frames on the new path, and communication path switching is completed.