Abstract: A communication system including: a first device that includes first and second units and a first encapsulation unit encapsulating data; a second device that includes a third unit communicating data with the second unit, a fourth unit, and a second encapsulation unit encapsulating data; a third device that includes a fifth unit communicating data with the first or third unit, a sixth unit, and a third encapsulation unit encapsulating data; and a fourth device that includes a seventh unit communicating data with the first or third unit, an eighth unit communicating data with the fifth unit, and a fourth encapsulation unit encapsulating data; wherein at least two of the first to fourth devices include control units that control the units that the at least two of the first to fourth devices have, so as not to transfer received data to other devices.

Abstract: From an observed packet, the hop number, which is the number of nodes that the packet has passed through, and a bottleneck bandwidth, which is a bottleneck for transmitting the packet, are determined so as to detect loss failures. Thereby, the subnet that transmitted the observed packet is located as a node in a topology tree on the basis of the determined hop count and bottleneck bandwidth. When a loss failure, by which the packet is lost, is detected, subnets that are inappropriately arranged are extracted from the arrangement in the topology tree of the loss-failure-detected subnet, and the arrangement of the extracted subnets is modified in order to resolve the inappropriateness.

Abstract: A network group determination device includes an acquisition section, a comparison section and a determination section. The acquisition section acquires first communication information representing a state of communication between a first repeater on a network and a specific network group on the network, and second communication information representing a state of communication between a second repeater on the network and the network group. The comparison section makes a comparison of a difference between the first communication information and the second communication information to third communication information between the first repeater and the second repeater. The determination section makes, according to a result of the comparison by the comparison section, a determination of a position of the network group with respect to the first repeater and the second repeater.

Abstract: A CPU executes a process including determining a core node among plural relay nodes on a basis of route information, acquiring a first and a second packets flowing between a server and a terminal apparatus, the second packet being transmitted on a basis of the first packet, calculating a first delay time on a basis of the first and the second packets, the first delay time relating to packet transmission between the server and the terminal apparatus, transmitting a third packet to the core node, receiving a response to the third packet from the core node, calculating a second delay time on a basis of the third packet and the response, the second delay time being a delay time of the core node, and calculating a third delay time being a delay time of an end node on a basis of the first and the second delay times.

Abstract: An abnormality locating apparatus locates an abnormal location in a network. An abnormal location judging part judges a normality or abnormality of a link based on a normality or abnormality of an observation flow, by acquiring information of links through which each observation flow passes, from a network route information storage that stores passing route information of observation flows passing through the links. A diagnosis accuracy judging part judges that an accuracy of judging the normality or abnormality of a connecting link connected to a first node deteriorates, by acquiring links connected to each relay node as connecting links from a relay node connecting link information storage that stores connecting link information of each relay node, and judging that a relay node having all connecting links thereof that are abnormal is the first node having all observation flows passing therethrough that are abnormal.

Abstract: A connection state estimating method includes: acquiring a network distance between respective devices in a communication network; assuming branch point candidates at which three devices extracted from the network are connected together; calculating the network distance between each of the assumed branch point candidates and each of the three devices; classifying all the branch point candidates assumed to be connected with one of the devices into groups on the basis of the network distance between the one device and each branch point candidate; calculating representative values of the network distances between each device and branch point candidates assumed to be connected with the device; and selecting a device from the devices assumed to be connected with one of the branch point candidates and the representative value relating to the selected device.

Abstract: Measurement agents in a network failure detecting system each configure a group together with other measurement agents that receive a service from the same provision server, and form a link to create a tree structure with a predetermined measurement agent in the group at its top. The measurement agent then receives measurement results from the other measurement agents in the group, and narrows down candidates of a failure location based on the received measurement results. The measurement agent transmits the narrowed candidates of the failure location to a surveillance server or one of the other measurement agents. The surveillance server then receives the transmitted candidates of the failure location, and specifies the failure location based on the received candidates of the failure location.

Abstract: A providing apparatus of service information provided over a network collects service information and/or service components provided over a network and is triggered by setting of a scenario (such as content such as a combination of service components or service information) to extract available service components for the scenario from the service information or the service components to generate integrated service information with the use of the service components based on the scenario. A scenario and a policy (selection criteria of service components) are set and the service components conforming to the policy are selected to create the integrated service information based on the scenario.

Abstract: A transmitter-side access point measures a transmission delay between the transmitter-side access point and a receiver-side access point, and calculates a threshold based on the transmission delay. Unless the amount of data from a source user terminal exceeds the threshold, the transmitter-side access point transmits data over a network in response to a request from the receiver-side access point. When the amount of data from the source user terminal exceeds the threshold, the data is transported as being stored in a physical medium to the receiver-side access point through transportation service. The receiver-side access point obtains the data from the transported physical medium, and transfers the data to a destination user terminal.

Abstract: A packet reception portion receives packets of user traffic transferred on the network. The received packets are transferred to an address extraction portion via a distribution portion, and the transmission source address and destination address are extracted. Based on these addresses, a packet generation portion generates probe packets the transfer destination of which is the address destination. A packet transmission portion transmits the probe packets to the network. The transmitted probe packets are received as probe response packets by the packet reception portion. The probe response packets received by the packet reception portion are transferred to a result storage portion via the distribution portion. The result storage portion stores transmission source addresses included in the probe packets in a result storage DB.

Abstract: A load distribution system performing load measurement and load distribution control efficiently at a high speed and capable of improving the quality of communication and reliability. A transmission byte count acquisition block acquires the number of transmission bytes on a destination address basis from a frame. A transmission byte count storage block stores the accumulated number of transmission bytes in a transmission byte count table. A transmission byte count report block transfers the number of transmission bytes stored in the transmission byte count table, at regular intervals. An overloaded-unit detection block compares the transferred number of transmission bytes and the number of transmission bytes that can be received by a load distribution unit and detects any overloaded load distribution unit. An assignment adjustment block adjusts the traffic assignment by reducing the volume of an assignment to any load distribution unit determined to be overloaded.

Abstract: A network control apparatus for controlling devices in a predetermined area of a communication network includes a request-receiving unit for receiving a first route-setting request, a database for storing device information and topology information, a request-range-judging unit for forming a judgment as to whether or not the first route-setting request is relevant to any of the controlled devices, and a request-transmitting unit for transmitting the first route-setting request to an upper-level network control apparatus in the case of the request-range-judging unit's judgment outcome indicating that the first route-setting request is irrelevant to any of the controlled devices.

Abstract: A load balancer includes a judging module judging based on a content of data received from a client whether or not an acknowledgement of the data is to be sent to the client, an acknowledging module sending the acknowledgement to the client in accordance with a result of the judgment by the judging module, a forwarding module forwarding the data received from the client to any of a plurality of servers, and a retransmission data storage module storing only the data the acknowledgement of which is sent to the client among data forwarded to the server in preparation for a retransmission to the server.

Abstract: A network control apparatus for controlling devices in a predetermined area of a communication network includes a request-receiving unit for receiving a first route-setting request, a database for storing device information and topology information, a request-range-judging unit for forming a judgment as to whether or not the first route-setting request is relevant to any of the controlled devices, and a request-transmitting unit for transmitting the first route-setting request to an upper-level network control apparatus in the case of the request-range-judging unit's judgment outcome indicating that the first route-setting request is irrelevant to any of the controlled devices.