Abstract: A path control apparatus of the present invention includes: a status change detecting unit that detects a status change of a network; a path calculating unit that decides a path in accordance with the status of the network; and a calculation execution node deciding unit that compares a shortest path tree, which is established before occurrence of a change in the status of the network calculated by the path calculating unit, with a shortest path tree, which is established after the occurrence of the change in the status of the network calculated by the path calculating unit, and creates information required for determining whether a node apparatus in the network needs a path update, when the change occurs in the status of the network.

Abstract: A communication quality monitoring device is provided which determines communication quality deterioration by variation of a transmission buffer length in session control irrespectively of generation/non-generation of a data loss. A packet transmission and quality monitoring device 11-1 which detects deterioration in communication quality based on a buffer length of a session control protocol includes a threshold value calculating unit 11-17 which calculates a threshold value for the determination of deterioration in communication quality according to a parameter related to congestion detection of the session control protocol, and a deterioration determining unit 11-18 which determines deterioration in communication quality by comparing the threshold value and the buffer length.

Abstract: A topology detection apparatus includes, in a network having a tree-type topology: a route overlap judgment part that judges an existence or non-existence of an overlap between: a first route between terminals whose connection position are known; and a second route between a terminal whose connection position is known and a terminal whose connection position is unknown; and a topology detection part which determines the network topology based on the existence or non-existence of the first route and the second route.

Abstract: A node apparatus wherein when a topology change occurs on a network used for packet transfer between node apparatuses, the node apparatus performs dynamic route control for establishing a new normal route. The node apparatus has a device that receives, from another node apparatus, a route control message which includes information required for route determination; a device that computes a route on the network based on the received route control message; a device that sends another node apparatus a route control message which includes information required for said another node apparatus to determine a route on the network; a device wherein when receiving the route control message, this device computes an operation start time for route control operation by the route computation and the message sending, based on a distance between a topology change part and said node apparatus of oneself; and a device that controls the execution of the route control operation based on the computed operation start time.

Abstract: From a time point of last confirmation of operation of the working device 51 until a time point of next confirmation, the standby device 52 receives the same packet as that whose transfer processing is executed by the working device from the interface units 521-1˜521-n, processes the packet by the transfer unit 522 and holds the processed packet in the accumulation units 525-1˜525-n. The device monitors an operation state of the working device 51 by an advertisement transmitted by the working device 51 and upon reception of the advertisement, responsively abandons the packet held in the accumulation units 525-1˜525-n. When determining that the working device 51 stops by non-arrival of an advertisement for a predetermined time period, the device sends out the packet held in the accumulation units 525-1˜525-n and switches processing so as to itself operate as a working device.

Abstract: When a failure occurs in a link or another relay device, a route control unit updates a routing table stored in a current routing table. Upon update, it acquires inhibit target route information indicating a route likely to cause a micro-loop in the updated routing table and registers it into an inhibit target table. If route update in an adjacent relay device is completed, an inhibit control unit deletes a route in which the adjacent relay device is set as a next transfer destination from the inhibit target table. A transfer processing unit determines a transfer route of a packet based on the current routing table and, if the determined transfer route is not registered in the inhibit target table, executes transfer of the packet. A micro-loop can be thereby reliably avoided when route switching in a network system where communication between plural networks is relayed by plural relay devices.

Abstract: A wireless multi-hop network is formed by exchanging a control message including a HELLO message and a topology message between a plurality of communication terminals. A communication terminal adjusts a control message transmission interval so as to reduce the control load according to its movement state and transmits a control message at a longer transmission interval as the movement becomes smaller. Moreover, when link information is updated, the communication terminal includes the sequence number of the HELLO message in the topology message transmitted. Thus, it is possible to realize stable communication in accordance with a movement characteristic with a small message transmission frequency.

Abstract: A routing protocol unit (11) of each node (1) in a delay tolerant network calculates the probability of distribution to the destination node based on the log of end-to-end paths to the destination node from the past to the present registered in a routing table (12). A DTN forward unit (13) of a source node determines a next hop node to be used to forward forwarding data, based on the calculated distribution probability of each node with respect to the destination node.

Abstract: An object of the present invention is to provide a communication apparatus capable of connecting required modules for use in protocol processing depending on a packet to be processed without previous setting of the execution order of the modules so as to perform packet processing. A communication apparatus retains meta-information for each module implementing a protocol and a calculating means (transmission path restriction calculating section) for calculating module connection order based on the meta-information and a packet to be processed. The meta-information includes: the type of services that each module can provide on a protocol stack; a rule according to which it is determined whether each module can execute processing of a packet to be processed; and module information on a result of the determination of whether or not each module can execute the processing of a packet to be processed.

Abstract: A load caused by an information sharing message in an upper layer is reduced. A node, which shares information by exchanging a message between neighboring nodes in a lower layer and an upper layer of a network, comprises a unit for determining whether or not to transmit a message for information sharing in the upper layer according to the contents of a state change in the neighboring nodes detected when a state change in the neighboring nodes in the lower layer is detected.

Abstract: In order to more efficiently use port resources, which are finite global address resources assigned to an address translation device, the address translation device holds a session-port assignment table showing a correspondence between an existing session and a local endpoint (port resource) in the address translation device, and a port assignment rule indicating port usage about assignable ports. An address translation unit translates address information of a packet received according to the correspondence between the existing session and the port resource shown in the session-port assignment table, and assigns the port according to the port usage indicated by the port assignment rule for a packet for opening a new session. An assignment rule update unit changes a ratio of the port usage in the port assignment rule while the correspondence between the existing session and the port resource in the session-port assignment table is not changed.

Abstract: The present invention provides a traffic engineering apparatus which performs traffic engineering, including: an optimal branch point determination unit which determines an optimal branch point in a network to realize a predetermined policy; and a traffic flow regulation unit which regulates a traffic flow rate into the local node during reception of traffic based on the optimal branch point determined by the optimal branch point determination unit.

Abstract: Load balancing manager assigns to each cluster member a filter rule so as to divide traffic processing by a predetermined rule. According to the assigned rule, each cluster member obtains a packet multicast by a neighbor node, on a data link with the neighbor node. Each cluster member detects a session of the obtained packet to perform predetermined processing such as recording and updating of a state and application of a firewall packet filter.

Abstract: A topology specifying apparatus 10 according to this invention includes, in a network having a tree type network topology, a route overlap determining section 4 configured to determine existence or non-existence of an overlap between a first route to a terminal having an unknown connection node and a second route between terminals having known connection nodes; and a topology specifying section 5 configured to determine a network topology based on the existence or non-existence of the overlap of the first route and the second route.

Abstract: In a multicast delivery system, A delivery server enciphers delivery data by using a current use cipher key to generate enciphered data and transmits a multicast packet containing the enciphered data and a current use key identifier indicative of a pair of the current use cipher key and a current use decipher key as current use keys. A key management server holds as a current use key data, a set of the current use decipher key and the current use key identifier, and transmits a set of the current use decipher key and the current use key identifier as a current use decipherment key data in response to a current use key data request.

Abstract: A path control method includes a procedure for developing a path control message including regional information in transmission on the network. The regional information designates a path and/or a path length for transmitting the path control message. The path control message includes a regional property for instructing each node as to how to process the regional information either in a strict manner or in a flexible manner. With reference to the regional information and/or the regional property, each node is capable of selecting a destination node to which the path control message is to be transmitted, stopping the further transmission of the path control message, or discarding the path control message.

Abstract: A server proxy (12), which is arranged between a distribution server (11) and a router (13a), adds quality information to a packet (19a) from the distribution server (11) to output a packet (19b). A plurality of reception terminal proxies (17a-17n), which are arranged immediately before respective reception terminals (18a-18n), remove the quality information from the packet (19b) distributed via a network (14) and routers (13b-13m), and distribute only necessary information to the respective reception terminals (18). Each reception terminal proxy (17) which includes a quality information acquisition unit (17A) acquires the quality information to transmit, from a quality information calculation/transmission unit (17B), the quality information (51) to an accumulation server (15). The accumulation server (15) saves, in a quality information database, packet quality information (52) for each reception terminal (18).

Abstract: To provide an apparatus that optimizes the wait time in node apparatuses performing a packet backup using a multipath. The apparatus uses statistic information related to the transmission qualities of the paths constituting the multipath, thereby determining the minimum wait time that satisfies a target packet backup rate.

Abstract: The overlay link calculation device which determines a link between nodes in an overlay network formed by layers of a higher order than a network layer, which includes a topology information obtaining unit which obtains topology information of the network layer and a link calculation which calculates an overlay link based on the obtained topology information.

Abstract: A router (1) introduces virtual interfaces (3-1-3-n) between network interfaces (2-1-2-n) and a routing processing unit (4). The virtual interfaces (3-1-3-n) function to conceal a state such as a hit of the network interfaces (2-1-2-n) from the routing processing unit (4). One virtual interface is provided for each of the network interfaces (2-1-2-n). In the virtual interfaces (3-1-3-n), an up state, a down state, and a hit state are prepared as the states which the link takes. In the case of the hit state, the virtual interfaces (3-1-3-n) do not notify the routing processing unit (4) of a change in link state.