Fujitsu Corporation

Ryoichi Mutoh

Toru Katagiri

Yasuki Fujii

Naoki Oguchi

Shinya Kano

Yuji Tochio

Kazuto Nishimura

Takashi Honda

Kanji Naito

Hiroyuki Kitajima

Hiroyuki Homma

Yosuke Takano

A communication system includes a transmitter configured to transmit a packet, a repeater configured to impose a bandwidth limit on the packet, a receiver configured to receive the packet on which the bandwidth limit is imposed, and a control device configured to set, when a reception interval of reception packets received by the receiver is longer than a transmission interval of packets transmitted to the repeater, a transmission rate in the transmitter in accordance with the reception interval.

Communication system, communication controller, communication control method, and medium

A communication control device including: a memory, and a processor coupled to the memory and the processor configured to: transmit packets from the communication control device to a network device at each of a plurality of transmission rates, acquire a plurality of index values respectively indicating amounts of packet loss at the plurality of transmission rates, specify, among the plurality of transmission rates, a first transmission rate on which a corresponding index value among the plurality of index values has a dependence, and specify an upper limit of a vacant band between the communication control device and the network device based on the first transmission rate.

Communication control device, communication control method, and computer readable storage medium for specifying an upper limit of a network connection

A frame transmitting apparatus includes a transmitting unit which transmits, when a change is made to a value in a predetermined field of a frame, the frame including the predetermined field with the changed value a predetermined number of times in succession. A frame receiving apparatus includes a receiving unit which receives the frame and an acceptance processing unit which recognizes the value in the predetermined field of the received frame and conducts acceptance processing. The acceptance processing unit compares, when the value is different from a currently accepted value, the value with an expected value; accepts the value when the value matches the expected value; and accepts, when the value does not match the expected value, the value after receiving the same value the predetermined number of times in succession.

Communication system and method therefor

At a node, a first receiver receives ring information from a first adjacent node. A second receiver receives ring information from a second adjacent node. A first transmitter transmits ring information obtained by adding first local ring information attached between the node and the second adjacent node to the ring information received by the first receiver, to the second adjacent node. A second transmitter transmits ring information obtained by adding second local ring information attached between the node and the first adjacent node to the ring information received by the second receiver, to the first adjacent node.

Node and ring information transmitting method

A network setup method used in a ring network including a plurality of transmission equipments. The method includes: transmitting a frame in the ring network; causing each of the transmission equipments to write an identifier to the frame according to a specified rule; determining whether or not a plurality of identifiers written to the frame by the plurality of transmission equipments satisfy a specified condition; and causing each of the transmission equipments to obtain a corresponding identifier according to the specified rule from among the plurality of identifiers, when the plurality of identifiers satisfy the specified condition.

Ring network setup method

A TCP node stores a congestion window size before congestion is detected, the congestion window size limiting the amount of data to be transmitted. If congestion is detected, the TCP node reduces a current congestion window size to a predetermined size. If path switching subsequently occurs after congestion is detected, the TCP node uses a round-trip time or bandwidth information of a path after switching to correct the congestion window size before congestion detection. The TCP node then changes the reduced congestion window size to the corrected size.

Information processing apparatus, congestion control method, and computer-readable recording medium

An apparatus switches paths in a wavelength-multiplexing network in which a first number of wavelengths each used for a path to transmit an optical signal are multiplexed into an optical fiber. The apparatus includes an entire switching unit and a second number of individual switching units where the second number is smaller than the first number. The entire switching unit is configured to perform a path-switching process for switching a path, simultaneously on all the first number of wavelengths when failures have occurred for all the first number of wavelengths. The second number of individual switching units are each configured to perform the path-switching process individually on one of a third number of wavelengths included in the first number of wavelengths when at least one failure has occurred for the third number of wavelengths where the third numbers is smaller than the first number.

Apparatus and method for switching paths in a wavelength-multiplexing network

A transmission apparatus includes a processor configured to recognize a number of working failures and a number of protection failures on a network for transmission of wavelength-multiplexed signal light, the number of working failures being the number of failures in signal light in wavelengths at a working entity and the number of protection failures being the number of failures in signal light in wavelengths at a protection entity, configured to perform path switching for each group of signal light in wavelengths that are different from each other and configured to select, when multiple failures occur, restoration processing, on a basis of the number of working failures and the number of protection failures.

Transmission apparatus and network protection method

A node apparatus in a ring network in which a protection path is provided that cycles around the ring network and transports a signal in a direction opposite to a signal transporting direction of the working path and in the event of a failure of the working path, a node apparatus adjacent to the failure loops back the signal flowing on the working path onto the protection path, the node apparatus comprising: allowable bandwidth storing unit which stores a maximum total bandwidth value, which represents the largest value among per-link total values of bandwidths that a plurality of working paths use on respective links connecting between the node apparatuses, as an allowable bandwidth for a shared path; and bandwidth control unit which controls the bandwidth of traffic flowing on the protection path, in accordance with the allowable bandwidth.

Node apparatus, ring network, and protection path bandwidth control method

In an inter-ring connection method and device interconnecting a plurality of RPR rings, an inter-ring connecting device (interconnecting station) determines whether or not an RPR frame received from one ring is a broadcast frame; and resets, when the RPR frame determined to be the broadcast frame is relayed to another ring, a ttl of the frame so that a predetermined point between the inter-ring connection device itself and another identical inter-ring connection device opposed within a ring to be relayed is a cleave point. Also, topology information of the one ring is transmitted to another ring; topology information of each ring is held in a topology database; and an RPR frame is relayed (unicasted) between the rings by referring to the topology database based on a destination address of the RPR frame.

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Kawasaki, Japan

Ryoichi Mutoh