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 communication device (1) which realizes communication with data distributed to a plurality of connections, a data division restoration processing unit (1-2), when transmitting data, receives data from an application processing unit (1-1), divides the data into an arbitrary number of blocks, stores information for restoring the block to original data within a TCP header and sends the data to a network processing unit (1-3) by using an arbitrary number of TCP connections, and when receiving data, refers to restoration information stored within the TCP header with respect to data of the plurality of TCP connections received from the network processing unit (1-3), identifies a divisional block, combines the blocks to restore data as of before division and sends the data to the application processing unit (1-1).

Abstract: A quality degradation point estimating method for estimating a quality degradation point in a directed link set through which a communication flow passed is provided. The quality degradation point estimating method has: (A) determining a test flow set for estimating a quality degradation point; and (B) estimating the quality degradation point in the directed link set by sending the test flow set to the network. The (A) step includes a step of setting the flow, which passes through a partial set as a part of the directed link set, as the test flow and adding the set test flow to the test flow set. The test flow is sent from the test terminal on the network to a predetermined node in the partial set. A response is obtained at the predetermined node, and the response is sent from the predetermined node to a predetermined terminal.

Abstract: A communication apparatus includes an arrival time estimation unit, connection selection unit, and network processing unit. The arrival time estimation unit estimates, for each block and each of a plurality of connections, an arrival time until a block generated by segmenting transmission data arrives from the apparatus at a final reception terminal or a merging apparatus through a network. The connection selection unit selects, for each block, a connection with the shortest arrival time from the plurality of connections on the basis of the estimation result. The network processing unit outputs each block to the network by using the selected connection. A data communication method and a data communication program are also disclosed.

Abstract: A transmission unit includes: transmission rate control means for controlling a transmission rate; first transmission error detecting means for detecting data loss caused due to congestion in a transmission network; and second transmission error detecting means for detecting data loss (for example, packet loss) caused due to data error in the communication network. In the transmission unit, the transmission rate control means controls the transmission rate separately for a case where the first transmission error detecting means has detected data loss and a case where the second transmission error detecting means has detected data loss caused due to data error.

Abstract: An electrical connector includes a housing and terminals made of a sheet metal, which are held by the housing. The plurality of terminals is arranged in a direction perpendicular to a contact surface of a contact section thereof, and is held by the housing. Each of the terminals has a held section to be held by the housing, a contact section to contact with a mating terminal, and a connecting section to be connected to a circuit board each forming a flat sheet surface. The contact section is formed to have a flat contact surface, which slidably contacts with the mating terminal and extends in a connector fitting direction.

Abstract: An electrical connector includes a housing and a plurality of terminals. Each of the terminals is formed of a sheet metal and held by the housing. Each of the terminals has a contact section to contact with a mating terminal and a connecting section to be connected to a circuit board each forming a continuous flat sheet surface. The contact section has a contact surface that slidably contacts with the mating terminal so as to extend in a connector fitting direction, and the plurality of terminals is arranged so that adjacent terminals have the contact surfaces parallel to each other.

Abstract: A semiconductor device performs operation in synchronization with a certain clock signal. The semiconductor device includes a control unit for outputting operation control information, a storage unit for storing data, a first operation unit for performing operation on first data in accordance with first operation control information, and a second operation unit for performing operation on second data in accordance with second operation control information. The first operation unit includes a plurality of operation circuits. The number of logic gates constituting the entire operation circuits is m. The second operation unit includes at least one operation circuit in which the number of logic gates is n (n>m). Each of the total delay of the operation unit or the total delay of the operation unit is set at a value equal to or less than the cycle of the clock signal.

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 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: A session identification unit (11) determines a session to which an incoming packet belongs, while a session relay unit (12-1-12-N) relays between a session with a transmission terminal and a session with a reception terminal. A packet scheduler (13) instructs and controls the delivery of packets from each session relay unit (12-1-12-N), and a delivery control unit (14) delivers packets from each session relay unit (12-1-12-N) based on the instruction. In the session relay unit (12-1), a transmission session processing unit (121-1) processes a session for transmitting data to the reception terminal, and a transmission buffer (122-1) stores received data until the end of a transmission. A reception session processing unit (123-1) processes a session for receiving data from the transmission terminal.

Abstract: A quality degradation point estimating method for estimating a quality degradation point in a directed link set through which a communication flow passed is provided. The quality degradation point estimating method has: (A) determining a test flow set for estimating a quality degradation point; and (B) estimating the quality degradation point in the directed link set by sending the test flow set to the network. The (A) step includes a step of setting the flow, which passes through a partial set as a part of the directed link set, as the test flow and adding the set test flow to the test flow set. The test flow is sent from the test terminal on the network to a predetermined node in the partial set. A response is obtained at the predetermined node, and the response is sent from the predetermined node to a predetermined terminal.

Abstract: In a communication device (1) which realizes communication with data distributed to a plurality of connections, a data division restoration processing unit (1-2), when transmitting data, receives data from an application processing unit (1-1), divides the data into an arbitrary number of blocks, stores information for restoring the block to original data within a TCP header and sends the data to a network processing unit (1-3) by using an arbitrary number of TCP connections, and when receiving data, refers to restoration information stored within the TCP header with respect to data of the plurality of TCP connections received from the network processing unit (1-3), identifies a divisional block, combines the blocks to restore data as of before division and sends the data to the application processing unit (1-1).

Abstract: A session identification unit (11) determines a session to which an incoming packet belongs, while a session relay unit (12-1-12-N) relays between a session with a transmission terminal and a session with a reception terminal. A packet scheduler (13) instructs and controls the delivery of packets from each session relay unit (12-1-12-N), and a delivery control unit (14) delivers packets from each session relay unit (12-1-12-N) based on the instruction. In the session relay unit (12-1), a transmission session processing unit (121-1) processes a session for transmitting data to the reception terminal, and a transmission buffer (122-1) stores received data until the end of a transmission. A reception session processing unit (123-1) processes a session for receiving data from the transmission terminal.

Abstract: Bandwidth control unit (123-1) controls data transfer from reception buffer (122-1) to transmission buffer (124-1). Transmission resumption ACK generation unit (126-1) generates an ACK packet instructing a transmission terminal to resume transmission while duplicate ACK generation unit (127-1) generates a duplicate ACK instructing the transmission terminal to reduce the transmission rate. Packet discarding ratio calculation unit (128-1) obtains a packet discarding ratio in a session to a reception terminal. According to a data amount remaining in the transmission buffer and the packet discarding ratio, control parameter calculation unit (129-1) changes the control parameter of the session to the reception terminal.

Abstract: A session relay apparatus includes a packet relay unit, session relay unit, storage unit, session state registration unit, and session state updating unit. Upon receiving a session initiation packet or an acknowledge packet to acknowledge the session initiation packet, the packet relay unit directly transmits the received packet to a transmission destination without rewriting the packet. The session relay unit terminates the session and relays data. The storage unit stores information of the session terminated by the session relay unit. The session state registration unit temporarily registers, in the storage unit, session information corresponding to the session whose establishment is requested upon receiving the session initiation packet. The session state updating unit defines the temporarily registered session information upon receiving the acknowledge packet. When the packet of the session with the defined session information is received, the session relay unit terminates the session and relays the data.

Abstract: An information processing system operated by an active system and a standby system can reduce the load of a status synchronizing process. In a pair of an active information processing device and a standby information processing device closest to a transmitting terminal in the information processing system, the standby information processing device is arranged closer to the transmitting terminal. In a pair of an active information processing device and a standby information processing device closest to a receiving terminal in the information processing system, the standby information processing device is arranged closer to the receiving terminal. In other pair, a standby information processing device can be arranged closer to either the transmitting terminal or the receiving terminal.

Abstract: A network environment capable of performing a smooth and comfortable TCP session operation is provided to a user. The session relay equipment includes a bridge portion which relays a session by which a sequence of packets are transmitted and received between terminals connected with each other via a network; a socket information table which has socket information containing (1) address information of the terminal and (2) protocol information used in the session, the socket information being associated with information on whether or not the session is to be terminated; and a service information table which has information on a communication service to be provided for each service provision unit, the communication service being identified based on predetermined information within a header of the packet. The bridge portion terminates the session and executes a communication service based on the information contained in the header of the packet and the socket information.

Abstract: A communication apparatus includes an arrival time estimation unit, connection selection unit, and network processing unit. The arrival time estimation unit estimates, for each block and each of a plurality of connections, an arrival time until a block generated by segmenting transmission data arrives from the apparatus at a final reception terminal or a merging apparatus through a network. The connection selection unit selects, for each block, a connection with the shortest arrival time from the plurality of connections on the basis of the estimation result. The network processing unit outputs each block to the network by using the selected connection. A data communication method and a data communication program are also disclosed.