Abstract: A protocol process to a reception traffic is executed by cluster members of a current use system and a backup system. The backup system discards the reception traffic subjected to the protocol process and only the current use system transfers the reception traffic to an AP. The AP makes an application process redundant in an independent method. The cluster member in charge of the protocol process to the reception traffic is determined by using a data in a lower layer and the cluster member in charge of the application process is determined by using a data in a higher layer after the protocol process.

Abstract: Disclosed is a node that includes a distributed hash table generation means that generates a distributed hash table which indicates the next node to which a message is to be transferred, using a link state routing protocol, a link state information that exchange unit sends and receives link state information, and a tree delivery control unit that determines the transfer destination of the link state information so that the link state information is delivered along a tree where the source node of the link state information is a root.

Abstract: A wireless multi-hop network communication terminal 11 uses a Hello information suppression function 21 to suppress a part of information included in a Hello message for a given time after start-up or a new neighbor terminal is detected, thereby reducing message length. Further, the communication terminal 11 uses a Hello interval adjustment function 22 to adjust and shorten a Hello interval during the suppression of the Hello message length. After canceling the suppression of the Hello message length, the communication terminal 11 calculates and establishes a second Hello interval that is shorter than the usual one. Furthermore, after canceling the second Hello interval, the communication terminal 11 reestablishes the steady-state Hello interval.

Abstract: Distribution processing control unit determines a main processing range and a sub-processing range whose charges are taken by a cluster member to which the unit belongs. Among packets multicast to a cluster system, a filter hands over packets matching with the main processing range and the sub-processing range to a session processing unit. The session processing unit conducts session processing (including processing of updating session information stored in a holding unit). Thereafter, when the packet matches with the main processing range, the session processing unit hands the packet over to a packet forwarding unit and when the packet matches with the sub-processing range, abandons the packet. When a cluster member in charge of main processing of a packet whose sub-processing is taken charge of by the cluster member in question develops a failure, a failure recovery unit changes the sub-processing range to the main processing range.

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 QoS routing apparatus as a node of a logical network to transmit data communicated between user's terminals comprises a relay unit discriminating whether or not flows of received data are measurement flows and transmitting said received data, a quality measurement unit measuring communication quality of links connected the own apparatus using the measurement flows, a quality accuracy setting unit determining measurement accuracy of the communication qualities of the respective links and a path setting unit prescribing transmission amounts of the measurement flows to the respective links. When the path setting unit prescribes the transmission amounts of the measurement flows, it applies a higher rate to a link which has been determined a lower measurement accuracy.

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: 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: A packet distribution system includes distribution server configured to transmit packets of a video image; a user terminal, a packet transfer apparatus configured to transfer the packets received through a network from the distribution server to the user terminal such that the video image is reproduced on the user terminal, and to generate timing data from the received packets. A reproducing apparatus is configured to receive the timing data from the packet transfer apparatus, to receive the packets from the distribution server, and to transmit the received packets to the center terminal based on the timing data such that the video image is reproduced on the center terminal.

Abstract: A measuring system of distribution quality of a video image includes a distribution server, an receiving terminal, an upstream side reception time data generating section, a downstream side reception time data generating section and a quality data measuring section. The distribution server is provided in a center to transmit packets for a video image through a network, and the receiving terminal is provided in a user home to receive the packets transmitted through the network from the distribution server. The upstream side reception time data generating section is provided in the center to generate an upstream side reception time data indicating a time when the distribution server transmits one of the packets. The downstream side reception time data generating section is provided for the user home to generate a downstream side reception time data indicating a time when the receiving terminal receives the packet.

Abstract: Each of cluster members (1-1) constituting a cluster system which functions as a router includes a session processor (15) and session state synchronization unit (16). If the session state of a session to which a packet input via a spare processing packet filter (13) belongs is not held in a session state holding unit (18), the session processor (15) newly registers the session state. When receiving a transfer rejection notification containing a session identifier of an unauthorized packet from a paired current cluster member, the session state synchronization unit (16) deletes a session state represented by the session identifier from the session state holding unit. If a cluster member which performs spare processing in a certain partial range has failed, the session state of this cluster member can be restored on a new cluster member added instead of the faulty cluster member, without largely increasing the communication cost.

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.

Abstract: To provide a wireless multi-hop network in which the stable bandwidth ensured communication can be made without causing a collision of time slots due to the terminal movement or reserving the slot again due to a route change on the path of end-to-end communication. A terminal makes a slot allocation request for 3 Hops to a slot allocation server. Since unique slots within the network are allocated by the slot allocation server, there is no interference with the slots by other terminals. The terminal transmits the packet by inserting the slot information into an option header. A forwarding terminal that forwards the packet decides the transmission slot based on the slot information in the option header and its own hop count at the time of forwarding the packet.

Abstract: A data transmission system includes a plurality of dynamic route control units each disposed for one of a plurality of interfaces provided in the data transmission system. The route control data prepared by the dynamic route control units are combined by a specified dynamic route control unit to obtain in-system route control data, which is delivered to all the dynamic route control units. Each dynamic route control unit calculates costs for the routes between the own system and other data transmission systems based on the in-system route control data and new route control data received.

Abstract: An active router and standby routers share routing information used for dynamic routing while in normal operation. Further, the active router and the standby routers share routing information obtained after route computation is performed according to a routing protocol. Thus, efficient operation can be achieved. Protocol engines (31a to 31d) communicate with routers (41 and 42) to compute a route to be selected for routing with respect to a corresponding protocol. When the routing information has changed, a shared routing information transmitter (33) transmits the routing information and the like to the standby routers. Each of the protocol engines in a router operating as an active router communicates with the routers (41 and 42) to compute a route to be selected for routing with respect to a corresponding protocol. When the routing information has changed, a shared routing information receiver (34) receives the routing information and the like transmitted from the protocol engine.

Abstract: A multicast packet transfer system includes a first packet transfer apparatus and a second packet transfer apparatus. The first packet transfer apparatus transmits transfer packet data relating to an IP header and a UDP header of a multicast packet when the multicast packet is received, rewrites a header section of the multicast packet to produce a unicast packet, and transmits the unicast packet. The second packet transfer apparatus receives the transfer packet data and the unicast packet, and reproduces the multicast packet based on the received unicast packet and the received transfer packet data.

Abstract: A data transfer method between a plurality of data transfer apparatuses, is attained by establishing peers between the plurality of data transfer apparatuses to store the established peers in a transfer route configuration data table as transfer route configuration data in each of the plurality of data transfer apparatuses; and by transferring a reception data to specific ones of the plurality of data transfer apparatuses based on the transfer route configuration data in each of the plurality of data transfer apparatuses.

Abstract: Multicast packet transferring apparatus and system with a multicast packet transferred from one transferring apparatus existing in one domain to another transferring apparatus existing in another domain, the former transferring apparatus converts the multicast packet fed from a transmitter to a unicast packet and transfers the converted packet to the latter transferring apparatus. The latter transferring apparatus reconstructs the original multicast packet from the received unicast packet and rewrites to replace a transmitter address contained in the reconstructed multicast packet with an address of the transferring apparatus and then transfers the rewritten multicast packet having the rewritten address to specified receivers.

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 an 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: Distribution processing control unit determines a main processing range and a sub-processing range whose charges are taken by a cluster member to which the unit belongs. Among packets multicast to a cluster system, a filter hands over packets matching with the main processing range and the sub-processing range to a session processing unit. The session processing unit conducts session processing (including processing of updating session information stored in a holding unit). Thereafter, when the packet matches with the main processing range, the session processing unit hands the packet over to a packet forwarding unit and when the packet matches with the sub-processing range, abandons the packet. When a cluster member in charge of main processing of a packet whose sub-processing is taken charge of by the cluster member in question develops a failure, a failure recovery unit changes the sub-processing range to the main processing range.