A set-up scheme for a cut-through connection in a network system capable of realizing a high throughput, low latency internetwork communication efficiently under an internet environment. A network node checks source/destination information of the transport layer and/or a source/destination information of the network layer of a received packet, and if the checked information satisfies a prescribed condition, determines the packet to be a trigger. Then, the network node instructs another node capable of initiating a set-up operation, which may be the network node itself, to initiate the set-up of the cut-through connection for traffic corresponding to the trigger packet.