Abstract: 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.

Abstract: The present invention provides a BGP route evaluation device and method. A message receiving section 101 receives a BGP Update message. A status detecting section 102 detects the active/inactive status of each BGP route on the basis of a pair of prefix and next hop registered in “Announce” and “Withdraw” of the BGP Update message. In a management table 104, the active/inactive status of each BGP route is managed. An update section 103 updates the registration contents of the management table 104 on the basis of the detection result of the active/inactive status. An evaluation section 105 evaluates each BGP route on the basis of the registration contents of the management table 104.

Abstract: 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.

Abstract: 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.

Abstract: The present invention provides a BGP route evaluation device and method. A message receiving section 101 receives a BGP Update message. A status detecting section 102 detects the active/inactive status of each BGP route on the basis of a pair of prefix and next hop registered in “Announce” and “Withdraw” of the BGP Update message. In a management table 104, the active/inactive status of each BGP route is managed. An update section 103 updates the registration contents of the management table 104 on the basis of the detection result of the active/inactive status. An evaluation section 105 evaluates each BGP route on the basis of the registration contents of the management table 104.

Abstract: 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.

Abstract: A method for classifying congestion paths based on packet delay in a plurality of paths between measurement nodes, has the following steps. First, it receives a measurement data unit including an origin node, a destination node, and a sent time and a received time in a received packet from the measurement node. Then, it arranges the measurement data units of the same origin node in order of sent time, and extracts a pair of measurement data units of which an interval time between the sent times of adjacent measurement data units is less than the threshold time. Then, it arranges the measurement data units of the same destination node in order of the received time, and extracts a pair of measurement data units of which an interval time between the received times of adjacent measurement data units is less than the threshold time.

Abstract: 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.

Abstract: A traffic monitoring system enabling a manager to manage a plurality of traffic monitors in a centralized manner with a desired specification and to effectively utilize a traffic analysis result of each traffic monitor for network management is provided. The manager 1 loads a management application program to the manager itself and executes the program (S1). The manager 1 transfers the management application program to each active monitor 2 to allow the management application program to be executed (S2 and S3). Each active monitor 2 provides an analysis result to the manager 1 in response to a request (S4) from the manager 1 (S5). Each active monitor 2 stops a packet analysis program in response to a request (S6) from the manager 1 and unloads the packet analysis program. After collecting the analysis result, the manager 1 stops and unloads the management application program (S8).