A first node apparatus in a network, the network including a plurality of node apparatuses, the plurality of node apparatuses including the first node apparatus and a second node apparatus, the first node apparatus and the second node apparatus being connected in a wired manner, the first node apparatus comprising: a plurality of ports (101-1,... 101-x), each of which is a port to connect, in the wired manner, the first node apparatus to another different node apparatus other than the first node apparatus among the plurality of node apparatuses; loop detection information storage means for storing first identification information and destination port distinguishing information in association with each other, wherein the first identification information uniquely identifies a first frame which has been transmitted from a first port of the first node apparatus, and the destination port distinguishing information distinguishes the first port; routing information storage means for storing routing information, the routing information associating each of the plurality of node apparatuses with state information for indicating whether frame transmission from each of the plurality of ports is feasible or not; receiving means for receiving, from the second node apparatus, a second frame that includes second identification information for uniquely identifying the second frame; routing information updating means for updating, when the second identification information is identical with the first identification information, the state information associated with a destination node apparatus that is a destination of the second frame so as to indicate that frame transmission from the first port is not feasible; and transmitting means for transmitting the second frame from a second port, wherein the transmitting means is configured to select the second port from which transmission of the second frame is feasible from among the plurality of ports, according to the state information associated by the routing information with the destination node apparatus. a plurality of ports (101-1,... 101-x), each of which is a port to connect, in the wired manner, the first node apparatus to another different node apparatus other than the first node apparatus among the plurality of node apparatuses; loop detection information storage means for storing first identification information and destination port distinguishing information in association with each other, wherein the first identification information uniquely identifies a first frame which has been transmitted from a first port of the first node apparatus, and the destination port distinguishing information distinguishes the first port; routing information storage means for storing routing information, the routing information associating each of the plurality of node apparatuses with state information for indicating whether frame transmission from each of the plurality of ports is feasible or not; receiving means for receiving, from the second node apparatus, a second frame that includes second identification information for uniquely identifying the second frame; routing information updating means for updating, when the second identification information is identical with the first identification information, the state information associated with a destination node apparatus that is a destination of the second frame so as to indicate that frame transmission from the first port is not feasible; and transmitting means for transmitting the second frame from a second port, wherein the transmitting means is configured to select the second port from which transmission of the second frame is feasible from among the plurality of ports, according to the state information associated by the routing information with the destination node apparatus.