Hitachi, Ltd.

Alaxala Networks Corporation

Hitachi Information Technology Co., Ltd.

Yoshihiko Sakata

Takeshi Aimoto

Nobuhito Matsuyama

Hideki Hinosugi

Atsushi Anzai

Takeki Yazaki

Hiroki Yano

Takeshi Kumagai

Kiyoshi Kohzuki

Shinsuke Nakashima

Yuichi Ishikawa

Shinichi Akahane

Kazuo Sugai

Kaoru Okano

A packet relay device comprises a distribution processing unit classifying traffics into groups and users based on header information of packets received; a calculation unit calculating available frame rate of each user from peak frame rate, minimum frame rate, and weight information set for each user; a scheduling control unit updating a transmission schedule point-in-time calculated based on the available frame rate of each user, and judging which packet should be transmitted in accordance with the transmission schedule point-in-time updated; and a shaping unit updating a transmission schedule point-in-time calculated based on the peak frame rate of each user, and performing a shaping of packets at the peak frame rate on each user basis in accordance with the transmission schedule point-in-time updated; and a priority-control processing unit performing a strict priority control over transmission of packets of each group in correspondence with degree of priority of each group.

Traffic shaping method and device

In a transmission system of transferring a packet input from a first device to a second device via a network, a receiver device comprises a storage module configured to successively accumulate received packets, which are transferred over a multiple transmission paths, in correlation to each of the multiple transmission paths, a packet selector configured to sequentially perform a packet selection process with respect to each of the received packets accumulated in the storage module, where after elapse of a predetermined time period since a receipt time of a first packet received by the receiver device, the packet selection process respectively reads out one packet for each of the multiple transmission paths among the received identical packets, which are accumulated in correlation to each of the multiple transmission paths, and selects one packet with higher reliability out of the read-out packets, and an output module configured to output the packet selected by the packet selector to the second device.

Receiver device, transmission system, and packet transmission method

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 one embodiment, a bandwidth monitoring device comprises a packet receiving circuit configured to receive packets; a counter configured to count a total packet length by adding up inputted packet lengths including a packet length of a next input packet and subtracting outputted packet lengths to produce a counted value; a timer configured to time a packet receiving time; a memory configured to store a number of packet receiving times and a number of counted values counted by the counter which correspond to the packet receiving times, respectively; a counter rate-of-change calculating portion configured to calculate a change rate by a first counted value corresponding to an oldest packet receiving time stored in the memory representing an oldest time at which a packet was received and a second counted value corresponding to a latest packet receiving time stored in the memory representing a latest time at which a packet was received; and a determining portion configured to decide whether the next input packet will be discarded based on a probability computed by the change rate and the counted value counted by the counter when the packet receiving circuit receives the next input packet.

Bandwidth monitoring device

A traffic shaping apparatus calculates a minimum transmission interval, an allowed transmission frame rate of a user frame, and a reference transmission interval for each user according to a minimum transmission frame rate and a peak transmission frame rate specified for each user. The traffic shaping apparatus also calculates a first estimated transmission time according to the reference transmission interval, and a second estimated transmission time according to the minimum transmission interval for each user. The traffic shaping apparatus determines the user having the earliest first estimated transmission time, and determines according to the second estimated transmission time of the user whether a user frame is to be transmitted.

Traffic shaping apparatus and traffic shaping method

Cells are discarded in conformity with the order of priority when congestion occurs by discarding cells of a traffic class without any special contract for a transfer rate at the time of setting up a connection. A node stores priority information concerning cell discard corresponding to a connection identifier and controls the cell discard in accordance with the discard condition determined by the accumulated number of cells for each connection in the node and cell priority.

Packet switching device and cell transfer method

Packet switching device and cell transfer control method

Growing community of inventors

Hadano, Japan

Yoshihiko Sakata