Abstract: A network control apparatus is configured to detect connection relationships among a plurality of network switches in a communication network. The network control apparatus transmits a control signal to a first network switch, where the control signal commands the first network switch to transmit a first topology detection signal from a first plurality of ports provided for the first network switch. The network control apparatus receives, from a second network switch that has received the first topology detection signal, a response signal including topology information that has been detected by the second network switch from the first topology detection signal, and, based on the topology information included in the response signal, controls selection of a target port, via which to transmit a second topology detection signal, from among a second plurality of ports provided for the second network switch.

Abstract: A control apparatus includes a generation unit to generate a plurality of entries to be supplied with the switch, the plurality of entries being stored in a storage, a transmission unit to transmit to the switch an integration entry that the plurality of entries is integrated in an integration rule, the switch storing the plurality of entries in a table used for processing input packets, an acquisition unit to acquire the plurality of entries from the storage, and a control unit to perform re-integration processing including generating a re-integration entry integrated the plurality of entries and an additional entry in a re-integration rule created based on content of the plurality of entries and the additional entry, the re-integration entry being transmitted to the switch.

Abstract: A network switch which is managed by one of plural controllers changes a processing scheme for an input signal of an unknown flow depending on a load of the controller managing the network switch.

Abstract: A transfer device in a network including a plurality of control devices includes a network connection device, memory, and a processor. The network connection device communicates a target packet as a target of a transferring process. The memory stores a transfer rule received by the network connection device from a determination device as a control device for determining a transfer rule indicating a method of a process performed by the transfer device. The processor judges whether or not disable information indicating that the transfer rule is not to be acquired from the determination device when a transfer rule applicable to the target packet is not stored in the memory is included in the target packet. When the disable information is included, the processor outputs the target packet to the network connection device without requesting the transfer rule. The network connection device transmits the target packet to another transfer device.

Abstract: An OpenFlow switch used in an OpenFlow network including a plurality of OpenFlow switches and an OpenFlow controller configured to control the plurality of OpenFlow switches includes: a failure detector configured to detect a failure of a link connected to the OpenFlow controller; and a channel management unit configured to establish an OpenFlow channel to transmit control information to the OpenFlow controller through another OpenFlow switch among the plurality of OpenFlow switches when a failure is detected by the failure detector.

Abstract: A control device configured to control a plurality of network switches provided in a plurality of communication paths including a first communication path and a second communication path, the control device includes a memory, and a processor coupled to the memory and configured to control the plurality of network switches so that one or more data flows pass through the first communication path, monitor a load of the control device, detect that a failure occurs in the first communication path, and determine, based on a number of the one or more data flows and the load of the control device, a path selecting method of selecting the second communication path as an alternative communication path through which the data flows are to be transmitted.

Abstract: The processor obtains a process time, which is a time taken for processing a control message when the control device requests that a target processing device, selected from among the plurality of processing devices, process a control message. When the process time has become longer than a first threshold, the processor determines which of a first and a second congestion has occurred based on whether the process time has become longer than a second threshold, which is greater than the first threshold. The first congestion occurs in the transfer devices used for a communication between the control device and the target processing device. The second congestion occurs in the target processing device. The network connection device transmits a request message requesting that a transfer route for which it has been determined that the control message is not processed in a device in which the congestion has occurred be set.

Abstract: A network control apparatus is configured to detect connection relationships among a plurality of network switches in a communication network. The network control apparatus transmits a control signal to a first network switch, where the control signal commands the first network switch to transmit a first topology detection signal from a first plurality of ports provided for the first network switch. The network control apparatus receives, from a second network switch that has received the first topology detection signal, a response signal including topology information that has been detected by the second network switch from the first topology detection signal, and, based on the topology information included in the response signal, controls selection of a target port, via which to transmit a second topology detection signal, from among a second plurality of ports provided for the second network switch.

Abstract: The processor obtains a process time, which is a time taken for processing a control message when the control device requests that a target processing device, selected from among the plurality of processing devices, process a control message. When the process time has become longer than a first threshold, the processor determines which of a first and a second congestion has occurred based on whether the process time has become longer than a second threshold, which is greater than the first threshold. The first congestion occurs in the transfer devices used for a communication between the control device and the target processing device. The second congestion occurs in the target processing device. The network connection device transmits a request message requesting that a transfer route for which it has been determined that the control message is not processed in a device in which the congestion has occurred be set.

Abstract: An OpenFlow switch used in an OpenFlow network including a plurality of OpenFlow switches and an OpenFlow controller configured to control the plurality of OpenFlow switches includes: a failure detector configured to detect a failure of a link connected to the OpenFlow controller; and a channel management unit configured to establish an OpenFlow channel to transmit control information to the OpenFlow controller through another OpenFlow switch among the plurality of OpenFlow switches when a failure is detected by the failure detector.

Abstract: A control apparatus includes a generation unit to generate a plurality of entries to be supplied with the switch, the plurality of entries being stored in a storage, a transmission unit to transmit to the switch an integration entry that the plurality of entries is integrated in an integration rule, the switch storing the plurality of entries in a table used for processing input packets, an acquisition unit to acquire the plurality of entries from the storage, and a control unit to perform re-integration processing including generating a re-integration entry integrated the plurality of entries and an additional entry in a re-integration rule created based on content of the plurality of entries and the additional entry, the re-integration entry being transmitted to the switch.

Abstract: A network control apparatus includes: a power consumption collecting unit configured to collect power consumption information measured by at least one electrical node included in an electrical layer network and at least one optical node included in an optical layer network; a cut-through range identifying unit configured to calculate an optical cut-through path based on the collected power consumption information; and a cut-through path setting instructing unit configured to instruct the electrical node and the optical node to set the optical cut-through path based on the calculation result in the cut-through range identifying unit.

Abstract: A transfer device in a network including a plurality of control devices includes a network connection device, memory, and a processor. The network connection device communicates a target packet as a target of a transferring process. The memory stores a transfer rule received by the network connection device from a determination device as a control device for determining a transfer rule indicating a method of a process performed by the transfer device. The processor judges whether or not disable information indicating that the transfer rule is not to be acquired from the determination device when a transfer rule applicable to the target packet is not stored in the memory is included in the target packet. When the disable information is included, the processor outputs the target packet to the network connection device without requesting the transfer rule. The network connection device transmits the target packet to another transfer device.

Abstract: A video quality monitoring method includes a distribution server measuring first video quality index values according to a full-reference method by comparing a video, distributed from the distribution server to a client through a network, with a degraded video, generated by causing multiple scenarios of quality degradation due to the network in the video in a pseudo manner, creating characteristic data of first quality degradation values, obtained by causing the quality degradation to vary with the scenarios at regular intervals, and the first video quality index values corresponding to the respective scenarios, and transmitting the characteristic data to the client; and the client measuring a second quality degradation value in the video distributed through the network, and calculating a second video quality index value, equivalent to a value according to the full-reference method, of the distributed video from the measured second quality degradation value and the characteristic data.

Abstract: A network control apparatus includes: a power consumption collecting unit configured to collect power consumption information measured by at least one electrical node included in an electrical layer network and at least one optical node included in an optical layer network; a cut-through range identifying unit configured to calculate an optical cut-through path based on the collected power consumption information; and a cut-through path setting instructing unit configured to instruct the electrical node and the optical node to set the optical cut-through path based on the calculation result in the cut-through range identifying unit.

Abstract: A video quality monitoring method includes a distribution server measuring first video quality index values according to a full-reference method by comparing a video, distributed from the distribution server to a client through a network, with a degraded video, generated by causing multiple scenarios of quality degradation due to the network in the video in a pseudo manner, creating characteristic data of first quality degradation values, obtained by causing the quality degradation to vary with the scenarios at regular intervals, and the first video quality index values corresponding to the respective scenarios, and transmitting the characteristic data to the client; and the client measuring a second quality degradation value in the video distributed through the network, and calculating a second video quality index value, equivalent to a value according to the full-reference method, of the distributed video from the measured second quality degradation value and the characteristic data.

Abstract: A video quality monitoring method includes a distribution server measuring first video quality index values according to a full-reference method by comparing a video, distributed from the distribution server to a client through a network, with a degraded video, generated by causing multiple scenarios of quality degradation due to the network in the video in a pseudo manner, creating characteristic data of first quality degradation values, obtained by causing the quality degradation to vary with the scenarios at regular intervals, and the first video quality index values corresponding to the respective scenarios, and transmitting the characteristic data to the client; and the client measuring a second quality degradation value in the video distributed through the network, and calculating a second video quality index value, equivalent to a value according to the full-reference method, of the distributed video from the measured second quality degradation value and the characteristic data.

Abstract: A video quality monitoring method includes a distribution server measuring first video quality index values according to a full-reference method by comparing a video, distributed from the distribution server to a client through a network, with a degraded video, generated by causing multiple scenarios of quality degradation due to the network in the video in a pseudo manner, creating characteristic data of first quality degradation values, obtained by causing the quality degradation to vary with the scenarios at regular intervals, and the first video quality index values corresponding to the respective scenarios, and transmitting the characteristic data to the client; and the client measuring a second quality degradation value in the video distributed through the network, and calculating a second video quality index value, equivalent to a value according to the full-reference method, of the distributed video from the measured second quality degradation value and the characteristic data.

Abstract: A recovery-path request message control block generates, sends, and receives a recovery-path request message containing failure location information and recovery-path setup information. A label assignment message control block generates, sends, and receives a label assignment message. A setup label information generation block generates setup label information. A recovery-path label table management block constructs and manages a recovery-path label table. A failure detection block detects the location of a failure. A failure notification message transfer block transfers a failure notification message containing failure location information. A recovery-path establishment block establishes a recovery-path by comparing failure location information contained in a failure notification message and failure location information contained in a recovery-path label table and by selecting setup label information corresponding to matching failure location information.

Abstract: A method of detecting a failure in a network, which includes a transport plane comprised of a plurality of communication nodes performing optical cross-connect and a control plane comprised of a plurality of control nodes that are connected to and control the respective communication nodes, includes the steps of transmitting, from a control node connected to a communication node having detected a failure to an adjacent control node, a failure information message having a time indication indicative of a time at which the failure is detected, and identifying, at a given control node which received the failure information message, a location of the failure in response to the time indication.