Abstract: An information processing device includes a processor to execute a process including: blocking, owing to remote control through a network, at least one of communication of a request transmitted by a first device and addressed to a second device, the communication being performed from a network device, disposed on a communication path between the first device and the second device, to the second device, and communication of a response transmitted by the second device and addressed to the first device; acquiring, from the network device, the request transmitted by the first device and addressed to the second device; and transmitting to the first device, an instruction for switching a transmission destination of the request to a third device.

Abstract: A method includes: identifying a test source address (SA) in a second network and a test destination address (DA) in a third network, wherein a packet is presumed to be transmitted from the second network to the third network through plural communication routes in a first network; causing an output edge router connected to the third network to change settings of an ARP table in the output edge router so as not to transfer the packet addressed to the test DA to the third network; obtaining the first number of input packets from each counting router on each route; transmitting a test packet including the test SA and DA, plural times; obtaining the second number of input packets from each counting router; calculating a difference between the first and second numbers for each route; and identifying a route through which the test packets passed, based on the differences.

Abstract: The monitoring method includes: detecting a cut link among a plurality of links forming a link aggregation; counting lost packets related to remaining links in the plurality of links excluding the cut link to obtain a first lost packet count for each first address included in packets passed through the remaining links; sorting the first lost packet counts into first segments corresponding to the remaining links; determining degradation in quality for each first segment on the basis of the first lost packet counts sorted into the first segments; determining whether the cut link is in failure on the basis of the determined degradation in quality for each first segment; and outputting a determination result of whether the cut link is in failure.

Abstract: A network verification system verifies a network to which a relay apparatus relays a packet. A test management apparatus includes a condition acquiring unit to acquire verification conditions which contain an unused network address as a test target and a registering unit to register, in an address resolution table of the relay apparatus, an entry in which the unused network address contained in the acquired verification conditions is associated with a physical address of the testing apparatus. A testing apparatus includes a test packet transmitting unit to transmit, when instructed by the test management apparatus, the plurality of test packets to form a plurality of connections based on the verification conditions, a test packet receiving unit to receive the plurality of test packets and a measuring unit to measure communication qualities with respect to the respective connections of the plurality of test packets.

Abstract: A method of specifying an input edge router has: obtaining a first value of an input packet counter from each of input candidate edge routers having possibility to receive a specified packet passing through a specified area; transmitting a test packet having a destination address of an output edge router supplying the specified packet or a test packet having a destination address of the specified packet, to a source router connected to a network indicated by a source address of the specified packet; obtaining a second value of the input packet counter from each of the input candidate edge routers; calculating a difference between the first and second values in each input candidate edge router; and specifying an input edge router through which the specified packet passes according to the difference.

Abstract: A test packet transmitting apparatus transmits respective test packets including different pieces of identification information to a repeating installation. The repeating installation makes a predetermined number of copies of each test packet received from the test packet transmitting apparatus to be transmitted to a test packet receiving apparatus, and determines the predetermined number of copies as a population to measure a communication quality. The test packet receiving device counts the received test packets according to each type of identification information.

Abstract: A monitoring apparatus that identifies a failure path in a network including a relay device includes a packet receiving unit configured to receive packets that are transmitted in the network and an identification unit configured to, when deterioration of quality is detected between a transmission source subnetwork and a destination subnetwork of the received packet based on information included in the received packet received by the packet receiving unit, perform a quality measurement on a plurality of packets that are estimated to be routed through different paths among a plurality of transmission paths between the transmission source subnetwork and the destination subnetwork based on a transmission source address or a destination address so as to identify which packet is a packet that is routed through the failure path.

Abstract: A communication path estimation method for estimating a communication path in a network in which communication is performed by forwarding packets from a plurality of transmission source nodes to a plurality of transmission destination nodes through a plurality of nodes, the method has obtaining, by a computer, path information of a plurality of paths, extracting a path in which a number of lost packets out of packets flowing in the extracted path is a predetermined value or more on the basis of the path information, choosing a pair of adjacent nodes included in the extracted path, and outputting a hypothesis that a static path is set from a first downstream node to a second downstream node when the first downstream node being included in a plurality of paths connected to a plurality of destination nodes and a first upstream node is the same with a second upstream node.

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 loop locating apparatus and method enabling simple and fast identification of a Layer 3 loop fault occurring in a network, wherein, when the possibility of a Layer 3 loop is detected, a loop locating command function unit makes a packet transmission/reception function unit send a series of inspection packets (Pis) with successively incremented TTLs and monitors the return packets (te) of the inspection packets (Pis) by a return number counting function unit and wherein a loop location decision function unit finds the routers returning packets (te) with remarkably larger return numbers than the others and identifies the routers with return numbers over a predetermined threshold as the location of occurrence of the loop.

Abstract: A method includes: identifying a test source address (SA) in a second network and a test destination address (DA) in a third network, wherein a packet is presumed to be transmitted from the second network to the third network through plural communication routes in a first network; causing an output edge router connected to the third network to change settings of an ARP table in the output edge router so as not to transfer the packet addressed to the test DA to the third network; obtaining the first number of input packets from each counting router on each route; transmitting a test packet including the test SA and DA, plural times; obtaining the second number of input packets from each counting router; calculating a difference between the first and second numbers for each route; and identifying a route through which the test packets passed, based on the differences.

Abstract: In order to preliminarily perform a load test or the like of an IP network, a test apparatus instructs a test packet transmitting device to transmit a test packet having a specified multicast address and instructs a test packet receiving device to receive the test packet of the multicast address. The test apparatus further instructs a first relay device to relay the test packet of the multicast address and instructs a second relay device to perform a route optimization excluding processing. The test packet receiving device requests the second relay device to transfer the test packet of the multicast address when the test packet receiving device has received the instruction to receive the test packet.

Abstract: A method of specifying an input edge router has: obtaining a first value of an input packet counter from each of input candidate edge routers having possibility to receive a specified packet passing through a specified area; transmitting a test packet having a destination address of an output edge router supplying the specified packet or a test packet having a destination address of the specified packet, to a source router connected to a network indicated by a source address of the specified packet; obtaining a second value of the input packet counter from each of the input candidate edge routers; calculating a difference between the first and second values in each input candidate edge router; and specifying an input edge router through which the specified packet passes according to the difference.

Abstract: In accordance with an instruction from a network monitoring device (4), a transmission terminal (2T) serving as a source of video information transmits a certain amount of monitoring test packets differentiated from the usual multicast frames. Pass status information (for example, MIB information) generated by routers (3) receiving and passing through the continuous test packets is collected at the network monitoring device (4). The device (4) uses the collected pass status information and topology information which the device (4) holds by itself so as to judge the direction of transmission of the test packets at the interface of each router (3) and specifies the multicast tree based on the results of judgment.

Abstract: A network verification system verifies a network to which a relay apparatus relays a packet. A test management apparatus includes a condition acquiring unit to acquire verification conditions which contain an unused network address as a test target and a registering unit to register, in an address resolution table of the relay apparatus, an entry in which the unused network address contained in the acquired verification conditions is associated with a physical address of the testing apparatus. A testing apparatus includes a test packet transmitting unit to transmit, when instructed by the test management apparatus, the plurality of test packets to form a plurality of connections based on the verification conditions, a test packet receiving unit to receive the plurality of test packets and a measuring unit to measure communication qualities with respect to the respective connections of the plurality of test packets.

Abstract: A test packet transmitting apparatus transmits respective test packets including different pieces of identification information to a repeating installation. The repeating installation makes a predetermined number of copies of each test packet received from the test packet transmitting apparatus to be transmitted to a test packet receiving apparatus, and determines the predetermined number of copies as a population to measure a communication quality. The test packet receiving device counts the received test packets according to each type of identification information.

Abstract: A layer 2 loop detection apparatus includes a unit recognizing a topology of an L2 network at normal time by collecting MIB information including information concerning ports of a plurality of L2 switches from the plurality of L2 switches through SNMP communication; a unit discriminating, based on a topology recognition processing, a blocking port for traffic blocking and a disable port under a port disable state each set under a Spanning Tree Protocol (STP); a unit setting each of the blocking port and the disable port as a monitoring point and periodically monitoring a state thereof; and a unit performing detection of an L2 loop by re-collecting a part of the MIB information from the plurality of L2 switches through SNMP communication and re-recognizing the topology of the L2 network, the detection of the L2 loop detection being triggered by a change of a state of one of the blocking port and the disable port.

Abstract: In accordance with an instruction from a network monitoring device (4), a transmission terminal (2T) serving as a source of video information transmits a certain amount of monitoring test packets differentiated from the usual multicast frames. Pass status information (for example, MIB information) generated by routers (3) receiving and passing through the continuous test packets is collected at the network monitoring device (4). The device (4) uses the collected pass status information and topology information which the device (4) holds by itself so as to judge the direction of transmission of the test packets at the interface of each router (3) and specifies the multicast tree based on the results of judgment.

Abstract: A plurality of traffic monitoring apparatuses and an entry managing apparatus common to the traffic monitoring apparatuses are provided in a network. In the traffic monitoring apparatus, a packet receiving unit extracts a source IP address, destination IP address, and a TTL count to be registered in an entry registering unit as an entry. A destination-address counting unit counts the number of entries having the same source IP address and the same TTL count. A TTL counting unit counts the number of entries having the same source IP address and the same destination IP address, and counts a largest TTL count. An entry reporting unit reports a TTL count or a largest TTL count to the entry managing apparatus. The entry managing apparatus identifies a traffic monitoring apparatus that has reported a TTL count having the largest value or a largest TTL count having the largest value, as an origin of an abnormality.

Abstract: A data distribution system capable of suppressing a fall of the efficiency of operation of a network due to repeated data retransmission in the network when distributing a large volume of data from a data distribution server on a data provider side to a data receiver side access server via the network. This data distribution system is comprised by a data distribution server, an access server for transferring intended data to each user, and a network cache apparatus provided in the network and having a cache function unit for temporarily storing the data from the data distribution server and an exchange function unit for routing the stored data to the access server corresponding to the destination user.