A router comprising: an input port section to which packets transmitted a plurality of times at a fixed interval and a control packet transmitted prior to the packets are input from a plurality of input channels, each of the packets being composed of one or more flits; a crossbar section that connects a plurality of input channels with a plurality of output channels, the plurality of input channels of the crossbar section receiving a plurality of outputs of the input port section; a flit arrival time management section (503, 503', 503-1 to 503-N, 503'-1 to 503'-N) that requires an output channel a plurality of times to the crossbar section before the flit arrival time, the output channel being an output channel from which the packets are expected to be output; a switch assignment section (509, 509') that performs, according to the request from the flit arrival time management section, input/output connection relationship setting processing of setting a connection relationship between the input channels and the output channels before the flit arrival time and, if there are a plurality of the requests and congestion of the requests occurs, arbitrates the requests before the flit arrival time for the input/output connection relationship setting processing; and a switch assignment verification section that verifies whether a result of the input/output connection relationship setting processing corresponds with the actual routing of the packets, wherein the flit arrival time management section acquires, from the control packet, control packet information including transmission start time of the packets and transmission interval of the packets, calculates flit arrival time which is the time at which a packet in the packets is received based on the control packet information, records the flit arrival time, the transmission interval included in the control packet information, and input and output channels of the control packet, and makes the request a plurality of times based on the recorded information, and the crossbar section performs switching of the arriving packets using a result of the input/output connection relationship processing, the router being characterized in that the number of times of transmission of the packets is recorded in the control packet, and the flit arrival time management section records the number of times of transmission of the packets recorded in the control packet and, when the number of times of arrival of the packets reaches the value of the number of times of transmission of the packets, deletes an entry of recording the flit arrival time recorded in the flit arrival time management section itself. an input port section to which packets transmitted a plurality of times at a fixed interval and a control packet transmitted prior to the packets are input from a plurality of input channels, each of the packets being composed of one or more flits; a crossbar section that connects a plurality of input channels with a plurality of output channels, the plurality of input channels of the crossbar section receiving a plurality of outputs of the input port section; a flit arrival time management section (503, 503', 503-1 to 503-N, 503'-1 to 503'-N) that requires an output channel a plurality of times to the crossbar section before the flit arrival time, the output channel being an output channel from which the packets are expected to be output; a switch assignment section (509, 509') that performs, according to the request from the flit arrival time management section, input/output connection relationship setting processing of setting a connection relationship between the input channels and the output channels before the flit arrival time and, if there are a plurality of the requests and congestion of the requests occurs, arbitrates the requests before the flit arrival time for the input/output connection relationship setting processing; and a switch assignment verification section that verifies whether a result of the input/output connection relationship setting processing corresponds with the actual routing of the packets, wherein the flit arrival time management section acquires, from the control packet, control packet information including transmission start time of the packets and transmission interval of the packets, calculates flit arrival time which is the time at which a packet in the packets is received based on the control packet information, records the flit arrival time, the transmission interval included in the control packet information, and input and output channels of the control packet, and makes the request a plurality of times based on the recorded information, and the crossbar section performs switching of the arriving packets using a result of the input/output connection relationship processing, the router being characterized in that the number of times of transmission of the packets is recorded in the control packet, and the flit arrival time management section records the number of times of transmission of the packets recorded in the control packet and, when the number of times of arrival of the packets reaches the value of the number of times of transmission of the packets, deletes an entry of recording the flit arrival time recorded in the flit arrival time management section itself.