Patent ID: 8000253

Claim:
A non-transitory computer readable storage medium containing instructions that, when executed by a computer, causes the computer that functions as a surveying node to perform: transmitting a request to a survey target node that returns a response formed of a plurality of response packets obtained by dividing the response only when the request formed of a plurality of request packets obtained by dividing the request is reconstructed; and determining that any of request packets has been discarded on a first route from the surveying node itself as a transmission source of the request to the survey target node when no response packet has been received at all from the survey target node, and determining that any of the response packets has been discarded on a second route from the survey target node to the surveying node itself as the transmission source of the request when one or more response packets have been received from the survey target node but the response cannot be reconstructed, wherein in the transmitting, the request is transmitted to the survey target node every time a determination process is performed in the determining until the number of times of transmission indicative of the number of times of transmitting the request reaches a predetermined number of time set in advance, and in the determining, the determination process is performed every time the request is transmitted in the transmitting, the instructions further cause the computer to perform: counting the number of times of discard of request indicative of the number of times of determining in the determining that any of the request packets has been discarded; and calculating an expected value representing, as a numerical value, a possibility of discarding each packet transmitted from the surveying node itself to the survey target node before the packet reaches the survey target node, based on the number of times of discard of request counted in the counting, the number of times of transmission, and the request division number indicative of the number of request packets generated by dividing the request.