Abstract: The disclosed access control apparatus and method controls an I/O device to perform processing of access requests in a predetermined order including inputting access requests from multiple tasks to cause the I/O device to perform file processing, storing and managing information about file priorities, obtaining a file priority corresponding to an access request, managing a queue having multiple queues for which the processing priorities corresponding to the file priorities are set and causing the access request to be stored in any of the queues corresponding to the file priority, and obtaining the access requests stored in the queues in an order based on the processing priorities set for the queues and sends the access requests to the I/O device.

Abstract: The disclosed access control apparatus and method controls an I/O device to perform processing of access requests in a predetermined order including inputting access requests from multiple tasks to cause the I/O device to perform file processing, storing and managing information about file priorities, obtaining a file priority corresponding to an access request, managing a queue having multiple queues for which the processing priorities corresponding to the file priorities are set and causing the access request to be stored in any of the queues corresponding to the file priority, and obtaining the access requests stored in the queues in an order based on the processing priorities set for the queues and sends the access requests to the I/O device.

Abstract: In a router supporting a packet relay function based on a routing table, and also a VPN (Virtual Private Network) function, an output port deciding portion decides an output port different from a normal output port indicated as an output port corresponding to a destination address of a communication confirming packet based on the routing table, and packet transmitter transmits the communication confirming packet through the decided output port. A communication confirming packet determining portion determines a communicating state based on a response packet for the communication confirming packet received from the destination router of the communication confirming packet returned from another router connected to the output port and relayed by its own router.

Abstract: A communications system in which both a layer-2 and layer-3 virtual private networks (VPNS) can operate in an efficient and cost-effective way to offer improved network services. An ingress edge node has a path data manager which sets and manages path data describing configuration of an intra-network transport path. For transport over the intra-network transport path, a labeling unit adds an intra-network transport label to each outgoing frame, based on the path data. Those frames also have a VPN label for transport over an end-to-end VPN path. In an egress edge node, a frame discrimination value setting unit gives a frame discrimination value for identifying to which VPN each received frame belongs. A redirection processor redirects the received frames to their destinations according to their VPN labels and frame discrimination value.

Abstract: A router includes a label-mapping-message receiving unit, a passing-node managing unit, and a passing-node selecting unit. The label-mapping-message receiving unit receives a label-mapping message including label information and PV TLV information from all adjacent nodes. The passing-node managing unit registers received label information and PV TLV information to manage the information. When a line fault occurs in a network, the passing-node selecting unit selects PV TLV information that does not include an identifier of the router itself from among registered PV TLV information. Thus, an optimal path is determined based on selected PV TLV information so that a loop does not occur in the network.

Abstract: In a router supporting a packet relay function based on a routing table, and also a VPN (Virtual Private Network) function, an output port deciding portion decides an output port different from a normal output port indicated as an output port corresponding to a destination address of a communication confirming packet based on the routing table, and packet transmitter transmits the communication confirming packet through the decided output port. A communication confirming packet determining portion determines a communicating state based on a response packet for the communication confirming packet received from the destination router of the communication confirming packet returned from another router connected to the output port and relayed by its own router.

Abstract: A communications system in which both a layer-2 and layer-3 virtual private networks (VPNS) can operate in an efficient and cost-effective way to offer improved network services. An ingress edge node has a path data manager which sets and manages path data describing configuration of an intra-network transport path. For transport over the intra-network transport path, a labeling unit adds an intra-network transport label to each outgoing frame, based on the path data. Those frames also have a VPN label for transport over an end-to-end VPN path. In an egress edge node, a frame discrimination value setting unit gives a frame discrimination value for identifying to which VPN each received frame belongs. A redirection processor redirects the received frames to their destinations according to their VPN labels and frame discrimination value.

Abstract: A data processing system which provides increased reliability by properly managing a plurality of basic modules. System configuration data is a collection of information regarding basic modules constituting each target system. Compatibility data is compiled to keep statistics of past failures occurred in a target system, which maintains the following associated records: properties of failed basic modules, properties of their related modules, failure types, and failure counts. When a basic module is changed in a target system, the target system sends out a notification message. This message is received by a notification message parser and supplied to a system configuration manager via a hardware change manager. The system configuration manager first consults the system configuration data to identify the changed basic module and its related basic modules, and then retrieves information about compatibility of such basic modules by consulting the compatibility data.