A switch includes a plurality of ports and a combination determining unit that determines a central processing unit (CPU) to be paired with one of the ports. The port includes: an arbitration circuit that selects the CPU to be paired therewith when receiving an arbitration request from the CPU to be paired in a predetermined state, and selects one of the CPUs from which the arbitration request has been received in other cases to return transmission permission; and a data transfer unit that transfers the received data from the selected CPU to another CPU. The CPU includes: a request transmission unit that transmits the arbitration request to the ports; and a data transmission unit that transmits data to the paired port when the arbitration request is transmitted to the paired port in the predetermined state, and transmits data to the ports that have returned transmission permission in other cases.