In order to preliminarily confirming whether or not a protection route to be switched over can be safely switched over during a working route being used in a unicast or multicast mode. a notification of communication confirmation/quality confirmation or multicast communication confirmation is received from a manager device is received. When the received unicast or multicast packet does not include an confirmation identifier instructed by the notification while the received unicast or multicast packet includes a destination network or multicast address instructed by the notification, the received packet is mirrored and the confirmation identifier is set in a predetermined area within a header of the packet to be transferred to a preselected protection route. When the received packet includes the destination network or multicast address and the confirmation identifier instructed by the notification, the manager device is notified of a result of the communication confirmation/quality confirmation and the packet is transferred to the protection route.