Kddi Corporation

Kddi R&d Laboratories, Inc.

Atsuo Tachibana

Shigehiro Ano

Toru Hasegawa

Atsushi Tagami

Masafumi Watari

A method is disclosed of detecting a failed link in a network over which nodes are interconnected via links. The nodes include an observer node and a managed node. This method, implemented for the observer node, includes: determining, for each of prefixes in receive route-update messages, a single normal-state path; determining, for each of the links (i.e., monitored links) on the normal-state path for the managed node, at least one prefix advertised from one of the nodes which is located adjacent to the each link on an upstream side, as at least one monitored prefix; determining whether the path contained in each route-update message, and the normal-state path for the monitored prefix contained in the each route-update message are unmatched with each other; counting, for each monitored link, an unmatched-prefix count which refers to a count of at least one unmatched prefix of the at least one monitored prefix for each monitored link; and extracting at least one link from the monitored links, as at least one failed link, based on the unmatched-prefix count.

Real-time detection of failed inter-node link in network

A method and a management apparatus for classifying congestion paths based on packet delay in a plurality of paths between measurement nodes. The method and the apparatus specify the short-time congestions based on packet delay in Internet Protocol network.

Method and management apparatus for classifying congestion paths based on packet delay

The present invention detects 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 consists of a source pair of networks and a destination pair of networks. The quality information values are inputted to elements in a matrix that all pairs of networks are put in same order as rows (or columns) of source pairs of networks and columns (or rows) of destination pairs of networks. If inferior quality values in the matrix line up in the row (or column), a failure is determined in a destination (or a source) pair of networks in column side (or row side) corresponding to a row (or a column). If inferior quality values line up in a slanting direction, a failure is determined in a route between the Internet service provider networks indicated to the slanting direction.

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Saitama, Japan

Atsuo Tachibana