Patent ID: 7321560

Claim:
A method for detecting a failure location of network in the Internet, a pair of networks consists of an access network and an Internet service provider network, and a route between terminals consists of a source pair of networks and a destination pair of networks, said method comprising the steps of: measuring quality information between said terminals on round robin combination that all pairs of networks are made into a source side and a destination side; inputting values indicating said quality information to elements in a matrix that all pairs of networks are put in same order as rows or columns corresponding to said source pairs of networks and columns or rows corresponding to destination pairs of networks; and determining that a failure is in a destination pair of networks in column side or in row side corresponding to a row or a column if inferior quality values in said matrix line up in said row or column, determining that a failure is in a source pair of networks in row side or in column side corresponding to a column or a row if inferior quality values in said matrix line up in said column or row, and determining that a failure is in a backbone route between said Internet service provider networks indicated to a slanting direction if inferior quality values in said matrix line up in said slanting direction.