A switch that performs packet forwarding processing based on a label for a connection in which a communication path is specified by the label, includes a receiving unit that receives loopback information with a label of a first layer used for packet forwarding for a first connection, and a packet processing unit that transmits a first loopback packet having a packet including the loopback information, a label of the first layer, and a label of a second layer used for packet forwarding for a second connection layered on the label of the first layer, and also transmits a second loopback packet having the packet including the loopback information and the label of the second layer.