Abstract: When a proxy device is used between a transmission terminal and a reception terminal, receives final data from the transmission terminal, and fails immediately thereafter, a situation is avoided where transmission is completed in the transmission terminal, but reception is not completed in the reception terminal. There is provided a means for not returning ACK when a data packet is received in a state in which there is no data which waits for ACK and transmission of which is in progress, and there is no data which waits for arrangement and reception of which is in progress in the proxy device, for returning ACK for data received one step before when a data packet is received in a state in which there is data which waits for ACK and transmission of which is in progress, or there is data which waits for arrangement and reception of which is in progress.

Abstract: A transmission apparatus includes: a sending unit configured to send data to a receiver apparatus via the network; a receiving unit configured to receive acknowledgement data including an acknowledgement and information on a receive window size from the receiver apparatus via the network; a transmission bandwidth controller configured to control a bandwidth for data to be sent from the sending unit; a transmission bandwidth restriction unit configured to restrict the bandwidth controlled by the transmission bandwidth controller in such a manner that a data size of data for which no acknowledgement is received from the receiver apparatus among data which is sent is equal to or smaller than an upper limit size determined from the receive window size; and a switching controller configured to switch activation and inactivation of the transmission bandwidth restriction unit based on the data size and the receive window size.

Abstract: A transmission apparatus includes: a sending unit configured to send data to a receiver apparatus via the network; a receiving unit configured to receive acknowledgement data including an acknowledgement and information on a receive window size from the receiver apparatus via the network; a transmission bandwidth controller configured to control a bandwidth for data to be sent from the sending unit; a transmission bandwidth restriction unit configured to restrict the bandwidth controlled by the transmission bandwidth controller in such a manner that a data size of data for which no acknowledgement is received from the receiver apparatus among data which is sent is equal to or smaller than an upper limit size determined from the receive window size; and a switching controller configured to switch activation and inactivation of the transmission bandwidth restriction unit based on the data size and the receive window size.

Abstract: To efficiently retransmit discarded packets and to reduce discarded location storage capacity, it is provided a communication apparatus to be coupled to a network, the communication apparatus being configured to: transmit data to a correspondent communication apparatus coupled to the network; receive an acknowledgement transmitted from the correspondent communication apparatus; monitor whether or not a storage capacity shortage for storing discarded locations of transmitted data in the correspondent communication apparatus; and retransmit data by setting a retransmission priority for discarded locations in a case of the storage capacity shortage.

Abstract: To prevent the switching time influences power saving efficiency and packet loss prevention performance, it is provided a network apparatus for transferring packets, including a transfer part for transferring received packets to a given destination, and a determining part for obtaining traffic volume of the packets to be transferred. The determining part determines periodicity of changes to the traffic volume, predicts traffic volume after a predetermined period of time with use of the determined periodicity, and controls transfer performance of the transfer part based on a result of the traffic volume prediction.

Abstract: Between network node apparatuses that operate as a duplex system, when a failure occurs in an information processing unit of one system, the service is maintained and continued in an information processing unit of the other system without interruption of the service. In a system using an active system network node apparatus 100-1 and a standby system network node apparatus 100-2 both in an operating state, a switch processing unit 110 has a transfer processing unit 112 that copies and transfers a packet flow to be a subject of information processing in the information processing unit 200 to two output destinations, when the switch processing unit operates as an active system.

Abstract: When a proxy device is used between a transmission terminal and a reception terminal, receives final data from the transmission terminal, and fails immediately thereafter, a situation is avoided where transmission is completed in the transmission terminal, but reception is not completed in the reception terminal. There is provided a means for not returning ACK when a data packet is received in a state in which there is no data which waits for ACK and transmission of which is in progress, and there is no data which waits for arrangement and reception of which is in progress in the proxy device, for returning ACK for data received one step before when a data packet is received in a state in which there is data which waits for ACK and transmission of which is in progress, or there is data which waits for arrangement and reception of which is in progress.

Abstract: To efficiently retransmit discarded packets and to reduce discarded location storage capacity, it is provided a communication apparatus to be coupled to a network, the communication apparatus being configured to: transmit data to a correspondent communication apparatus coupled to the network; receive an acknowledgement transmitted from the correspondent communication apparatus; monitor whether or not a storage capacity shortage for storing discarded locations of transmitted data in the correspondent communication apparatus; and retransmit data by setting a retransmission priority for discarded locations in a case of the storage capacity shortage.

Abstract: An object of the present invention is to measure a packet loss rate by using information included in a general communication protocol. In a network including a transmission terminal, a communication line, and a reception terminal, the transmission terminal adds a number denoting a packet order to a transmission packet and transmits the transmission packet, and the reception terminal is a system using a protocol in which an order of packets, which have been received, is returned as an acknowledgement, and a system using a selective acknowledgement to notify of reception of discontinuous data when the reception terminal receives the discontinuous data. A method for measuring a packet loss rate by using a number of transmission packets and information on an acknowledgement and a selective acknowledgement is provided in the transmission terminal.

Abstract: When a proxy device is used between a transmission terminal and a reception terminal, receives final data from the transmission terminal, and fails immediately thereafter, a situation is avoided where transmission is completed in the transmission terminal, but reception is not completed in the reception terminal. There is provided a means for not returning ACK when a data packet is received in a state in which there is no data which waits for ACK and transmission of which is in progress, and there is no data which waits for arrangement and reception of which is in progress in the proxy device, for returning ACK for data received one step before when a data packet is received in a state in which there is data which waits for ACK and transmission of which is in progress, or there is data which waits for arrangement and reception of which is in progress.

Abstract: There is provided a communication device for controlling an upper limit bandwidth of TCP communication for transmission. There is further provided a communication device for enhancing a communication bandwidth for TCP and restricting it to an upper limit for transmission by use of new TCP for enhancing a communication bandwidth. The device comprises a transmission bandwidth control unit for determining a communication bandwidth of each session of TCP or new TCP, a token bucket update unit for determining whether packets are transmittable per session, and a maximum bandwidth control unit for determining whether packets are transmittable based on an upper limit of a total sum of all the set sessions, wherein when the maximum bandwidth control unit determines that packets are transmittable, the token bucket update unit transmits packets of a session determined as transmittable.

Abstract: A bandwidth monitoring device for use in a network for transferring priority packets in preference to non priority packets as far as the amount of the priority packets is within a contract bandwidth established between a network user and a network operator, comprising a bandwidth check result decision unit for detecting whether the bandwidth of the priority packets is less than the contract bandwidth, and a DSCP decision unit for determining that a non priority packet may be transferred as a priority packet when the bandwidth of the priority packets is less than the contract bandwidth thereby to sufficiently use the contract bandwidth.

Abstract: Packet communication apparatus connects plural LANs to each other, in termination of a WAN that conducts data communication using handshake communication protocol. Apparatus buffers data packets between the LANs, and transfers, as a proxy, response packets and data packets to a terminal device. The apparatus stops transmission of data packets belonging to an arbitrary packet flow when the reception of the response packets belonging to the packet flow from the WAN is ceased for a network outage detection time or more set, while transmitting data packets belonging to the arbitrary packet flow. The apparatus retransmits a first data packet whose corresponding response packet is not received, belonging to the packet flow immediately after the data packet transmission stops, and retransmits all data packets whose corresponding response packets are not received, belonging to the packet flow, when receiving the response packets from the WAN.

Abstract: An edge router measures a traffic volume inputted into a network, and the measurement result is notified to a network management server. If the network management server judges that the notified traffic volume is “smaller” than a capacity of a second core router, it will direct a first core router to shift to a power saving mode. The first core router notifies the edge router of the shift to the power saving mode, and the edge router updates a routing table so that the packet to the first core router may be bypassed to the second core router. The first core router shifts to the power saving mode that does not perform packet transfer, and reduction in electric power is realized.

Abstract: A display apparatus including: a collecting unit that collects power consumption information, wherein the power consumption information shows power consumption of a connecting device, and the connecting device interconnects a plurality of communication paths in a computer network; and a display unit that displays power consumption of the computer network, based on the power consumption information and constituent units based on a virtual network which is configured virtually on the computer network.

Abstract: In a distributed information communication processing system in which a plurality of information communication devices provides a service through a network, response speed, electric power consumption, and further reliability are improved. The distributed information communication processing system which provides various services is configured by associating an entrance node (EN) which executes filtering near sensors, actuators, and terminals being information sources, an intelligent node (IN) which changes an information processing position and executes information processing and communication processing instead of a data center (DC), and a management node (MN) which manages these nodes. Thereby, real time type information processing can be realized.

Abstract: A system permitting alteration of the information processing position, where an existing information system is used, while minimizing alterations in configuration or the like, is to be provided. Intelligent nodes each having an information processing section and any desired address altering section are arranged on boundaries of a network where packets are likely to pass. This node has a flow table for recognizing as a flow a group of packets transmitted from each user's terminal, a flow status table for determining the connection state and the next destination address or the final destination address of each flow, and a module to observe the loaded state of its own information processing function. It rewrites the destination address of any flow not in a connection-established state in the flow status table to a less loaded one out of its own information processing function section or external information processing apparatus.

Abstract: To prevent the switching time influences power saving efficiency and packet loss prevention performance, it is provided a network apparatus for transferring packets, including a transfer part for transferring received packets to a given destination, and a determining part for obtaining traffic volume of the packets to be transferred. The determining part determines periodicity of changes to the traffic volume, predicts traffic volume after a predetermined period of time with use of the determined periodicity, and controls transfer performance of the transfer part based on a result of the traffic volume prediction.

Abstract: When a delay between a packet relay device and a receiving terminal increases, congestion notifications are delayed, and communication quality declines. When a flow is assessed to be in a congestion state, a packet delay device overwrites, within a packet header of an acknowledgement packet for the flow which is received thereafter from a receiving terminal, a field which denotes a network congestion state with a value which denotes that a congestion state is in effect, and transmits same as an acknowledgement packet. It is thus possible to issue a congestion notification over a path from the packet relay device to the receiving terminal, eliminating a congestion notification path from the packet relay device to the receiving terminal and from the receiving terminal to the packet relay device, facilitating avoiding a decline in communication quality even if the delay between the packet relay device and the receiving terminal increases.

Abstract: A traffic shaper which includes a cell buffer for temporarily storing an ATM cell arrived thereat, a first calculator for calculating an estimated cell sending time according to a VC contracted bandwidth, a second calculator for calculating an estimated cell sending time according to a VP contracted bandwidth, a binary tree VP sorting circuit for determining VP to be sent in top priority, a binary tree VC sorting circuit for determining VC to be sent in top priority, and a sending circuit for sending a cell in which the determined VP and VC are both brought to a transmittable state. The VP estimated sending time is revised according to the VC estimated sending time.