Patent ID: 8224626
Filing Date: 2012-07-17
Classification: H04L

Abstract:
1. A quality degradation point estimating method of estimating a quality degradation point in a directed link set through which a communication flow has passed on a network, comprising: (A) determining a test flow set for estimating the quality degradation point; and (B) estimating the quality degradation point in a directed link set by sending the test flow set to said network, wherein said (A) determining comprises: setting a flow, which passes through a partial set as a part of the directed link set, as a test flow; and adding the set test flow to the test flow set, and the test flow is sent from a test terminal on said network to a predetermined node in the partial set, a response is obtained at said predetermined node, and the response is sent from said predetermined node to a predetermined terminal, wherein the predetermined node is a terminal on said network other than said test terminal and other than said predetermined terminal, wherein said predetermined terminal receiving the response is said test terminal, wherein said (A) determining comprises: (a) setting continuous directed links included in the directed link set as the partial set, and setting an interval of the continuous directed links as a directed link interval; (b) setting the flow, which passes through at least a part of the directed link interval, as the test flow; (c) adding the set test flow to the test flow set; (d1) determining a route from each of terminals which can generate the flow in the directed link interval, to said end point of the directed link interval; (d2) setting one of said terminals corresponding to the route having the longest overlap with the directed link interval, of the determined routes, as said test terminal; (e1) setting the link set included in the directed link interval as an indefinite link set, if said test terminal is not found out; and (e2) updating the directed link set by removing the indefinite link set from the directed link set, and wherein the test flow is sent from said test terminal to said predetermined node in the directed link interval, the response is obtained at said predetermined node, and the response is sent from said predetermined node to said predetermined terminal.