Test method for network system

A non-transitory computer-readable medium encoded with a computer program for performing a load test for a network system, the network system including a plurality of node devices, a first switch device coupling to the plurality of node devices, and a second switch device coupling to the first switch device, the first switch device being located between the plurality of node devices and the second switch device, the program when executed by a computer causes the computer to perform a method comprising:

• transmitting a plurality of first packets from a first node device among the plurality of node devices to the first switch device, the plurality of first packets being addressed to the first node device itself via both the first switch device and the second switch device;
• transmitting a plurality of second packets from a second node device among the plurality of node devices to the first switch device, in parallel with the transmitting of the plurality of first packets from the first node device to the first switch device, the plurality of second packets being addressed to the first node device via the first switch device without being routed through the second switch device;
• storing the first packets received from the second switch device and the second packets received from the second node device in a queue buffer and thereafter transferring the first packets and the second packets to the first node device by the first switch device;
• and
• monitoring state information based on a number of packets waiting to be exchanged in the second switch device.