Abstract: A network system includes a server which accommodates a plurality of tenants, at least one network appliance which has a resource shared by the plurality of tenants, a plurality of switches arranged between the at least one network appliance and a network; and a controller which controls the switches. Each switch has a flow table indicating an association of an input source with a transfer destination of packets for each flow, and transfers packets received from the input source to the transfer destination by referring to the flow table. The controller includes an assignment control block which dynamically assigns each of a plurality of tenants to any of the at least one network appliance; a route design block which designs a flow route for each of the tenants; and a switch setting block which sets the flow table for each of switches along the designed route.

Abstract: When an appliance, which has a packet discard function, discards a packet, transmits packet discard information as information related to the discarded packet to a controller. A controller performs a switch control process in response to the packet discard information. In the switch control process, the controller selects a target switch from the network, creates entry setting information for instructing the target switch to create an entry such that a packet belonging to the same flow as the discarded packet is discarded, and transmits the created entry setting information to the target switch. The target switch sets an entry in its own flow table in response to the entry setting information transmitted from the controller.

Abstract: A network distribution monitoring method is executed by a computer which configures each of a plurality of nodes, in a network which comprises the plurality of nodes which are connected with a management network.

Abstract: A network system includes a server which accommodates a plurality of tenants, at least one network appliance which has a resource shared by the plurality of tenants, a plurality of switches arranged between the at least one network appliance and a network; and a controller which controls the switches. Each switch has a flow table indicating an association of an input source with a transfer destination of packets for each flow, and transfers packets received from the input source to the transfer destination by referring to the flow table. The controller includes an assignment control block which dynamically assigns each of a plurality of tenants to any of the at least one network appliance; a route design block which designs a flow route for each of the tenants; and a switch setting block which sets the flow table for each of switches along the designed route.

Abstract: When an appliance, which has a packet discard function, discards a packet, transmits packet discard information as information related to the discarded packet to a controller. A controller performs a switch control process in response to the packet discard information. In the switch control process, the controller selects a target switch from the network, creates entry setting information for instructing the target switch to create an entry such that a packet belonging to the same flow as the discarded packet is discarded, and transmits the created entry setting information to the target switch. The target switch sets an entry in its own flow table in response to the entry setting information transmitted from the controller.

Abstract: A network distribution monitoring method is executed by a computer which configures each of a plurality of nodes, in a network which comprises the plurality of nodes which are connected with a management network.

Abstract: Disclosed are the multiplex communication system and the method therefore. A fault detection part of a duplex switching device detects it as generation of fault when recognizable signals are not detected from a connected line within a prescribed time. When the fault detection part detects the generation of fault in the present system line, the line switching part switches the lines from the present line to the standby line to perform communication between a terminal device and another terminal device therethrough. Also, the fault detection part notifies the generation of fault to the other duplex switching device after a prescribed switching protection time has passed from the time of the fault detected by the fault detection part, so the selection of the lines becomes consistent.

Abstract: A receiving unit receives data of a specific protocol, transmitted from a server to a client. An extraction unit extracts status codes from the received data. A classification unit classifies the extracted status codes, into first-type status codes and second-type status codes. A judgment unit finds a receiving rate of first-type status codes and a receiving rate of second-type status codes and compares the receiving rate of first-type status codes against a threshold value thereof, and the receiving rate of second-type status codes against a threshold value thereof. From results of comparison, the judgment unit then determines whether an increase in server load has resulted from a normal traffic or an abnormal traffic.

Abstract: Disclosed are the multiplex communication system and the method therefore. A fault detection part of a duplex switching device detects it as generation of fault when recognizable signals are not detected from a connected line within a prescribed time. When the fault detection part detects the generation of fault in the present system line, the line switching part switches the lines from the present line to the standby line to perform communication between a terminal device and another terminal device therethrough. Also, the fault detection part notifies the generation of fault to the other duplex switching device after a prescribed switching protection time has passed from the time of the fault detected by the fault detection part, so the selection of the lines becomes consistent.

Abstract: Disclosed are the multiplex communication system and the method therefore. A fault detection part of a duplex switching device detects it as generation of fault when recognizable signals are not detected from a connected line within a prescribed time. When the fault detection part detects the generation of fault in the present system line, the line switching part switches the lines from the present line to the standby line to perform communication between a terminal device and another terminal device therethrough. Also, the fault detection part notifies the generation of fault to the other duplex switching device after a prescribed switching protection time has passed from the time of the fault detected by the fault detection part, so the selection of the lines becomes consistent.

Abstract: Disclosed are the multiplex communication system and the method therefore. A fault detection part of a duplex switching device detects it as generation of fault when recognizable signals are not detected from a connected line within a prescribed time. When the fault detection part detects the generation of fault in the present system line, the line switching part switches the lines from the present line to the standby line to perform communication between a terminal device and another terminal device therethrough. Also, the fault detection part notifies the generation of fault to the other duplex switching device after a prescribed switching protection time has passed from the time of the fault detected by the fault detection part, so the selection of the lines becomes consistent.