Patent ID: 7545750

Claim:
A network failure detection apparatus, a first terminal among a plurality of terminals, for detecting a failure in a network in which each terminal is connected to another terminal via at least one relay unit among a plurality of relay units, said network failure detection apparatus comprising: a communication section acquiring statistic information related to data received in each of a plurality of ports of the first relay unit, from a first relay unit among the plurality of relay units; and a decision section deciding whether or not a loop causing a predetermined network failure is occurred in the first relay unit, or deciding the direction from the first relay unit to another relay unit having the loop occurred therein, based on the statistic information, wherein the statistic information is a received data amount, or the number of received data, on a port-by-port basis of the first relay unit, and when the number of ports each having the received data amount, or the number of received data, per unit time being no less than a predetermined threshold is two, the decision section decides that the loop is occurred in the first relay unit, while when the number of ports each having the received data amount per unit time being no less than the predetermined threshold is one, the decision section decides that another relay unit having the loop occurred therein exists in the downstream direction of the port.