A first node device is included in a network including a plurality of node devices including a plurality of terminals and a plurality of relay devices relaying a packet transmitted and received between the plurality of terminals. The first node device includes a memory, and a processor coupled to the memory and the processor configured to determine whether a second node device detects a possibility of disappearance of a first packet in the network, the first packet being transmitted from a third node device to the second node device, and when determining that the second node device detects the possibility, transmit first information to a respective node device on one or more paths present between the first node device and the third node device in the network, the first information requesting to determine whether the respective node device transmits or receives the first packet.