Hitachi, Ltd.

Alaxala Networks Corporation

Other

Hitachi Information Technology Co., Ltd.

Takeki Yazaki

Takeshi Aimoto

Yuichi Ishikawa

Nobuhito Matsuyama

Kazuo Sugai

Shinichi Akahane

Takashi Isobe

Michitaka Okuno

Mitsuru Nagasaka

Yoshihito Sako

Tomohiko Tanabe

Kiyoshi Kohzuki

Tomoyuki Oku

Noriyuki Tanaka

Yoshinori Yamamura

Yuji Tsushima

Masayuki Takase

Teruo Kaganoi

Minoru Hidaka

Yoshihiko Sakata

Yasuhiro Kodama

Takuro Mori

Hidetaka Aoki

Tomohiko Kouno

Toshio Shimojo

Masaki Yamada

Shinji Nishimura

Yuji Ogata

Yasusi Kanada

Yuji Oishi

Rinne Watanabe

Naoki Tanida

Tetsuya Oohashi

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.

Communication device and communication system

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.

Communication apparatus

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.

Communication apparatus and packet transfer method

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.

Network apparatus, performance control method, and network system

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-and a standby system network node apparatus-both in an operating state, a switch processing unithas a transfer processing unitthat copies and transfers a packet flow to be a subject of information processing in the information processing unitto two output destinations, when the switch processing unit operates as an active system. The information processing unithas a mutual monitoring processing unitthat checks mutual operating states between the active system and the standby system, determines that a failure has occurred when the active system does not return a response and causes the standby system to operate as an active system, and a halt processing unit that, upon operation as the information processing unit of the standby system, halts output of a packet to be a subject of information processing.

Network node apparatus system, apparatus, and method

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.

Bandwidth monitoring method and its device

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.

Packet communication apparatus and packet communication method

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.

Packet transfer method, packet transfer device, and packet transfer system

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.

Assessing conditions of power consumption in computer network

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.

Information and communication processing system, method, and network node

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.

Distributed router computing at network nodes

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.

Communication device with multi-stages of traffic shaping functions

A packet forwarding device changes packet transfer performance according to a packet load, and ensures communication quality of an important packet while transfer performance is made minimum to suppress power consumption. The packet forwarding device includes a measuring section to measure the packet load for each packet importance degree, an estimation section to estimate a future packet load for each importance degree based on the measurement result, a performance determination section to determine performance for an operation based on the estimated load, which are provided in, for example, a traffic estimation/performance determination section. Reduction in the power consumption and assurance of the communication quality of the important packet are realized by a minimum performance determination based on an important packet estimation load in the performance determination section and a preferential process of the important packet in the packet forwarding device.

Packet forwarding device

A data transfer apparatus is provided for monitoring the bandwidth of a first and a second flow, comprises flow detecting means for comparing information in a header field of a packet with the first and second detection conditions to detect a flow to which the packet belongs, compliance/violation determining means for measuring the bandwidth of the packet belonging to the detected flow to determine whether the packet complies with or violates a traffic condition which is set corresponding to each flow detection condition, and packet processing determining means for determining processing for a packet which satisfies both the first and second flow conditions based on the compliance/violation determination results corresponding to both traffic conditions, and determining processing for a packet which satisfies one of the first and second flow conditions based on the compliance/violation result corresponding to the flow detection condition satisfied by the packet.

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Hachioji, Japan

Takeki Yazaki