Hitachi, Ltd.

Alaxala Networks Corporation

Other

Hitachi Information Technology Co., Ltd.

Hitachi Microcomputer

Takeshi Aimoto

Takeki Yazaki

Nobuhito Matsuyama

Kazuo Sugai

Yoshihito Sako

Yoshihiko Sakata

Kiyoshi Kohzuki

Tomohiko Tanabe

Kenichi Sakamoto

Shinichi Akahane

Koji Wakayama

Hiroshi Iwamoto

Yuichi Ishikawa

Takehisa Hayashi

Satoshi Yoshizawa

Hidenori Inouchi

Yoshinori Watanabe

Hideki Murayama

Haruyuki Nakayama

Noriyuki Tanaka

Yoshinori Yamamura

Shoichi Murase

Hidemitsu Higuchi

Norihiko Moriwaki

Noboru Endo

Takashi Isobe

Takahisa Miyamoto

Teruo Kaganoi

Hiroki Yano

Kazuhiro Hashimoto

Hiroshi Ohguro

Shinichi Tanabe

Kenji Nakajima

Kunio Uchiyama

Atsushi Hasegawa

Tadahiko Nishimukai

Toshio Doi

Masabumi Shibata

Takeshi Kumagai

Tomoyuki Iijima

Atsushi Anzai

Hiroshi Sekino

Akira Ishiyama

Hiroyasu Kimura

Hidenori Kosugi

Naohisa Koie

Kaoru Okano

Noboru Tanabe

It is intended to reduce a power consumption without degrading a communication quality of a packet transfer device. One or more of a receiver, a switch unit, and a transmitter include a QoS control circuit for applying QoS control to received packets. There is provided a power saving operation mode that enables power saving operation by changing a grain size of the QoS control according to a flow rate of the packets, and controlling whether or not to supply an electric power to the QoS control circuit or a part of the QoS control circuit, according to the flow rate of the packets.

Packet transfer device and power supply control method for QoS control circuit

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

A relay device of relaying a communication packet is disclosed, which comprises: an input module configured to receive the communication packet as an input; a buffer configured to have a plurality of queues and temporarily accumulated the received communication packet; a sorter configured to sort the received communication packet to one of the plurality of queues, depending on a specific value obtained by a predetermined function that gives an aggregate output from an input which is transfer information regarding transfer of the communication packet; and a band controller configured to control a bandwidth for each of the plurality of queues and output communication packets accumulated in the plurality of queues for transmission of the communication packets. This ensures the quality of service, while saving the capacity of the buffer used for the queues.

Relay device and relay method

A packet switch for switching variable length packets. Each output port interface of the packet switch includes a buffer memory, a transmission priority controller, and a packet readout controller. The buffer memory stores transmission packets. The transmission priority controller classifies, based on a predetermined algorithm, transmission packets passed from a packet switching unit into a plurality of queue groups to which individual bandwidths are assigned respectively, and queues the transmission packets in the buffer memory so as to form a plurality of queues according to transmission priority in each of the queue groups. The packet readout controller reads the transmission packets from each of the queue groups in the buffer memory according to the order of transmission priority of the packets while guaranteeing the bandwidth assigned to the queue group.

Packet switch and switching method for switching variable length packets

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 network management/apparatus connected to a plurality of packet relay apparatuses constituting a group through a network includes an energy saving level calculation unit for calculating an energy saving level of each of the packet relay apparatuses on the basis of a CPU usage ratio of the packet relay apparatus managed or a difference between the present energy saving level and the energy saving level of minimum guarantee of the packet relay apparatus, and an energy saving function setting unit for setting an energy saving function of the packet relay apparatuses on the basis of the energy saving level calculated by the energy saving level calculation unit.

Network management apparatus

A network controller, capable of high-speed extraction of malicious traffic from networks and determining characteristics of such traffic, includes a unit for accumulating a number of packets for each arbitrary itemset included in the header portions of packets to be transferred, and a unit for determining whether the accumulated value obtained by the accumulating unit exceeds a predetermined threshold, and determines the types of packets to be transferred from accumulated values of the itemset and an itemset different from the itemset when the number of packets exceed a threshold.

Network controller and control method with flow analysis and control function

A switching system includes a data collection device, one or more switching devices. The data collection device is for collection of first data subject to specific processing. The switching devices directly or indirectly connected to the data collection device. At least one of the switching devices includes a determination module that determines whether received data is the first data or is second data which is not subject to the specific processing, and a marking module that puts first marking on the received data determined to be the first data. The switching devices respectively includes a transferring processor that executes a first transfer process for sending the received data to the data collection device when the received data has the first marking, and a second transfer process that sends the received data to the specified destination when the received data does not have the first marking.

Switching system and method in switching system

A packet forwarding device with a shaping unit, which is provided with queues for storing high priority packets and queues for storing low priority packets. The shaping unit transmits a packet read out from the non priority queue by giving a high priority when no transmit-wait packet exist in the priority queue even though the time to transmit a packet from the priority queue is reached.

Packet forwarding device and packet priority setting method

In order to allow priority transfer (fluctuation) over VLL packets while keeping each contracted bandwidth constantly, a leaky bucket model is expanded to have a thresholdfor permitting transmission of a packet (e.g. a WFQ packet) other than an LLQ packet and a threshold(larger than the threshold) for permitting transmission of the LLQ packet (two-threshold leaky bucket model). In this manner, even when a WFQ cannot be transmitted, an LLQ can be transmitted with priority. In addition, while the total bandwidth of the WFQ and LLQ, i.e. the bandwidth of the VLL contains fluctuation, the contracted bandwidth can be complied with. The circuit of the model is provided in LLQ and WFQ transmission appointed time calculating circuits so as to calculate respective transmission appointed times so that an LLQ/WFQ is selected and a packet is selected based on the times considering priority.

Traffic shaping circuit, terminal device and network node

A packet information extraction circuit derives predetermined key information (for example, destination information or transmission source information) from a received packet. A HASH result computation circuit generates m (a plurality of) pseudo-random numbers (HASH results) of fixed length from the derived information. A cache table holds the key information and cumulative packet lengths within a predetermined time period by using the generated pseudo-random numbers as addresses. When a threshold value holding and comparing circuit senses that the cumulative packet length has exceeded a value held therein, it sends a notification signal to judgment means disposed in a packet exchange system. The key information items and the cumulative values of the packet lengths are stored in the cache table on the basis of the received packets in such a way that larger cumulative packet lengths are left behind, whereas smaller cumulative packet lengths are erased.

Excessive flow detection device, excessive flow detection circuit, terminal apparatus and network node

A packet communication system of the present invention has first mode, second mode and third mode to apply to input packets. The first mode is a mode that decides priority of the packet by at least one of the address information and the application information, the second mode is a mode that decides priority of the packet by the DS value, the third mode is a mode that decides rewrite the DS value by at least one of the address information and the application information. A control unit of the packet communication system switches a mode to apply an input packet of the first mode, the second mode and the third mode based on the packet header information of the input packet.

Packet communication system with QoS control function

An input interface segments a variable length packet into plurality of fixed length cells and generates an internal switching information based on the header information of the variable length packet. The input interface transmits the information to a switch and, after that, transmits the cells as the following cells of the information to the switch. The switch performs switching processing to the succeeding cells based on the information. Therefore, the information is not added to the cells. When an input interface starts to transmit cells generated from a packet to its destination output interface through the switch, the switch is reserved until all the cells arrive at the output interfaces.

Variable length packet communication device

In a bandwidth policing apparatus which accommodates a large number of user groups, bandwidth policing for each user group is performed at high speed. When there is any extra bandwidth in bandwidth for a user group, the contracted committed information rate for each user is guaranteed invariably while using this effectively. The bandwidth policing apparatus accumulates packets of a plurality of user groups under bandwidth policing in the same packet accumulate FIFO. Also, for a packet which does not exceed the contracted bandwidth for each user, the contracted bandwidth for each user is guaranteed by deciding that the packet does not exceed the contracted bandwidth for each user group.

Bandwidth policing method and packet transfer apparatus with bandwidth policing function

Growing community of inventors

Sagamihara, Japan

Takeshi Aimoto