An information processing system includes a plurality of nodes; a plurality of first switches respectively including information on a node to which the first switch is coupled; and a plurality of second switches respectively including information on an aggregation which the second switch is in charge of, wherein a first node transmits a first packet including destination information indicating that a destination is a second node, to a first switch coupled to the first node, and the first switch coupled to the first node transmits the first packet to a second switch that is in charge of an aggregation to which the second node belongs, when the second node is not coupled to the first switch, and the second switch transmits the first packet to a first switch coupled to the second node, and the first switch coupled to the second node transmits the first packet to the second node.