Patent ID: 8036121

Claim:
A quality degradation portion estimating method on a network, comprising: passively measuring, by a passive measuring unit connected with a management target network, end-to-end (E2E) flow quality data on a route from a transmitting terminal connected with a different network to a receiving terminal connected with the management target network and upstream flow quality data on the route from the transmitting terminal to said passive measuring unit in the management target network; collecting the E2E flow quality data and the upstream flow quality data which are measured by said passive measuring unit; detecting a quality degradation flow in the management target network, said detected quality degradation flow being a flow related to the E2E flow quality data that does not show degradation of flow quality for the upstream flow quality data related to the same transmitting and receiving terminals, from among the E2E flow quality data which show the degradation of flow quality; and estimating a quality degradation portion in the management target network based on the quality degradation flow in the management target network and route data of the management target network, wherein said estimating comprises: referring to network component quality degradation probabilities to estimate as a quality degradation portion, a network component contained in a combination that quality degradation probability is the highest, from among combinations of faults of the network components which cause the quality degradation in the quality degradation flow in the management target network.