Patent ID: 8169932

Claim:
A QoS (Quality of Service) degradation point estimation method comprising the steps of: before generating a flow link table which associates QoS of a flow going through a network with a link the flow passes through, setting H to a value that is ½ of the total number of links in the network, and selecting, in ascending order of an absolute value of a difference between H and the number of links to pass, a predetermined number of flows as flows to be registered in the flow link table or selecting, in ascending order of the absolute value of the difference between H and the number of links to pass, flows having absolute values between H and the number of links to pass that are not more than a predetermined threshold as flows to be registered in the flow link table; generating the flow link table based on the QoS of the flow going through the network and path information of the network; and estimating a QoS degradation link as a QoS degradation point on the network based on the flow link table.