Abstract: A network management system in which usability and efficiency in management and maintenance of a network are improved. In the network management system, a network decomposition unit decomposes the network into network components, a table management unit manages information on the decomposition of the network into the network components by tabulating the information on the decomposition, and a virtual-network generation unit generates a virtual network as a new area to be managed, by combining the network components based on the information on the decomposition.

Abstract: Backup connection information table 151 having a data of a backup connection included in an alternative route is stored in a storage unit 15 of a network management system 1. On receiving failure occurrence notice of currently-used path, management table operating unit 13 creates based on backup connection information 151 an alternative route management table 153 having a data of backup connection included in the alternative route corresponding to failed currently-used path and registers the alternative route management table 153 in the storage unit 15. On receiving creation notice of a backup connection included in the alternative route, failure recovery determining unit 14 sets a setting status of the backup connection in the alternative route management table 153 to a setting completion and when all the setting status of backup connections included in the alternative route become the setting completion, determines a recovery of failed currently-used path has completed.

Abstract: A network management system in plural networks connected to each other, which offers the improved efficiency and convenience of network maintenance and management. When collecting and managing subnetwork information out of device information as device subnetworks in plural networks connected to each other, a subnetwork manager divides the device subnetwork of a connecting device belonging to the plural networks into plural divided subnetworks corresponding to the plural networks for management. A user interface controls the display of the device subnetworks and plural divided subnetworks.

Abstract: A communications network system, which is comprised of a management network, a control network, and a user transmission network, includes signaling-based communication apparatuses, each consisting of a control node and a communication node, and non-signaling-based communication apparatuses without having associated control nodes. In this system, a path can be established in a user data transmission network by controlling a signaling process on the control network. The configuration of the communication node of the non-signaling-based communication apparatus is changed by a network management system provided in the management network, while the configuration of the communication nodes of the signaling-based communication apparatus are changed by the associated control nodes by successively transmitting a signaling message to the next control node on the control network.

Abstract: A spare path design method for a communication network in which spare path information is set in each node of the communication network constituted of a plurality of nodes based on a database, a fault notification message including fault location information is transferred from a fault detection node to each node when a link fault or a node fault occurs. The nodes receiving the fault notification message switch the path in parallel. The spare path design method includes comparing the maximum fault notification time among the nodes located on a second spare path with the maximum fault notification time among the nodes located on a first spare path when a resource sharing condition is satisfied; and as a result of the comparison, if the time in the second path is shorter, replacing the spare path by the second spare path to update spare path information stored in the database.

Abstract: A protecting route design method is disclosed for a communication network including a plurality of nodes having preset information on a protecting route to switch over in parallel from a working route thereto when link or node failure occurs, according to a failure notification message including failure location information being transmitted from a failure detection node to each node. The protecting route design method includes the steps of searching a protecting route which can minimize a transfer time of the failure notification message from the failure detection node; and then, updating the searched protecting route to a protecting route having a spare communication capacity sharable for a different failure and having a route switchover time to be completed within a given time limit.

Abstract: A path switching system and method for a multiple-node ATM network, in which a plurality of paths can be simultaneously switched preserving proper correspondence thereof. A key choosing unit provided in a node chooses first and second sorting keys out of the virtual paths between the nodes, based on a first and second path information stored in a path information memory unit. Two nodes located at both ends of the route failed due to trouble in the ATM network select a first pair of isolated virtual paths having the first sorting key, which were formerly connected to the failed route, and connect them to a first bypass route. The two nodes then connect in a similar way a second pair of isolated virtual paths both having the second sorting key to a second bypass route.

Abstract: A communication system using a network route establishing technique for a network having a plurality of nodes connected through links, in which a route search message is delivered simultaneously in a plurality of directions from a sender node through a network route to a destination node, and a confirmation is delivered from the destination through the network route back to the sender node, and accordingly, a network route is established. The communication system includes a device for detecting, at a node through which a search message is to be transmitted, a possibility of a transmission of the search message beyond the node, a device for delivering a cancel message in the direction from which the search message has been transmitted, and a device for releasing the network route engaged by the search message, based on the delivered cancel message.

Abstract: A system for searching for alternative routes in a network at the time of a failure in a node or link which executes a stage for initiation of failure restoration processing which starts up failure restoration processing in accordance with various types of messages when a failure occurs at a link or node, a stage for processing a restoration message for searching for an alternative route, a stage for processing an acknowledgment message for reserving an alternative route, a stage for processing a cancellation message for cancelling reservation of an alternative route, a stage for processing a confirmation message for confirming a reserved alternative route and making a switching of cross-connect equipment, a stage for processing a cross-connection completion message for notifying the completion of switching of the cross-connect equipment to the nodes, a stage for processing a cross-connection acknowledgment message for confirming the completion of switching of all of the cross-connect equipment on the alterna

Abstract: A method for structuring a communications network based on an asynchronous transfer mode in which communications are held with the use of cells transferred between a node on the upstream side and a node on the downstream side. The method for structuring the network includes a step for preparing a plurality of VPI conversion tables for converting VPIs of the cell input under normal communicating conditions and that of the cell input in the event of a failure and outputting the cell with the VPI converted. The prepared VPI conversion tables are reorganized for each node and the reorganized VPI conversion tables are distributed to all nodes. Then, an alternate route monitoring and switching virtual path is set up in each alternate route and a monitoring cell is periodically transmitted along the alternate route.

Abstract: A route switching system in a communications network constituted of a transmitter and a receiver connected by a plurality of routes for switching a first route along which communication is being held by transmission of cells to a second route causing no blocking. The route switching system comprises a first switch provided in the transmitter for switching input cells from one route to another and outputting the cells, a first storage portion provided in the transmitter for storing the input cells, a second switch provided in the receiver for switching input cells from one route to another and outputting the cells, and a second storage portion provided in the receiver for storing the input cells. At the time when the route is switched over, the first switch is changed over so that the cells are transmitted through the first storage portion and, on the receiver side, the second switch is changed over so that the cells transmitted over the second route are stored into the second storage portion.

Abstract: A method includes the steps of a failure which occurs in a node or link, and b) identifying at most N (N is an integer equal to or greater than 2) nodes contained in each path affected by the occurrence of the failure. Each path is connected to a sender node which detects the failure, information is transferred to the sender node via the N nodes, and the sender node serves as a start point of each alternate path which is to be established. The method also includes the step of c) broadcasting a restoration message to links which outgo from the sender node, where the restoration message has an identifier of the sender node and identifiers of the N nodes specified for each path affected by the occurrence of the failure. The identifiers of the N nodes specified for each path being candidate nodes of an end point of each alternate path.