Fujitsu Corporation

Syunsuke Koga

Yuji Takahashi

Tadashige Iwao

Kenji Yamada

Kentaro Ikemoto

Yuichi Inao

Yayoi Nomura

Yuri Noguchi

Kentaro Masubuchi

Chiaki Nakajima

Tatsuya Toyozumi

Tetsu Yamamoto

Katsuhiko Yamatsu

Takayuki Okamasu

Kazuya Kawashima

Yasuhiro Kurogi

Hidefumi Takaoka

Masato Miyake

Yuichiro Taniguchi

A communication apparatus includes a receiver, a memory, a processor, and a transmitter. The receiver receives a route information frame and a first frame that is not the route information frame. The memory holds a route information table. The route information table records route information included in the route information frame. When the route information table does not include the source address of the first frame, the processor associates the source address with the address of a transfer-source apparatus that has transferred the first frame to the receiver, and registers these addresses in a registration table. In order to transmit a second frame addressed to a destination apparatus that is not recorded in the route information table, the processor obtains the address of a transfer-source apparatus registered in association with the address of the destination apparatus. The transmitter transmits the second frame to the address obtained by the processor.

Communication method and communication apparatus

A communication control method to be executed by a communication device, includes: transmitting, to one or more communication devices coupled to the communication device, a packet in which a destination is set; and determining, based on the number of paths that are among paths extending through the one or more communication devices to the destination and through which a response to the packet is received from the destination, the number of times of retransmission in the transmission of another packet to the destination.

Communication control method, network system, and communication device

Each of the nodes counts the number of other nodes located in a communication area of the node among nodes in a multi-hop network, and determines the number of times to retransmit a frame based on the counted number of the other nodes. Each of the nodes transmits a frame to a destination node, and repeats retransmission of the frame the determined number of times until receiving a response to the transmitted frame. Subsequently, each of the nodes changes a route to the destination node to another route when it does not receive the response after repeating the retransmissions the determined number of times.

Transmission control method, node, and non-transitory computer-readable recording medium

A method and a device perform time-synchronization with an ad hoc network configured by a plurality of nodes. The method includes: transmitting a time-synchronization request frame including an address of one of the plurality of nodes which belong to the ad hoc network to one of the plurality of nodes having a function of receiving the time-synchronization request frame and transmitting a time-synchronization reply frame including time-synchronization information; receiving the time-synchronization reply frame including the time-synchronization information from one of the plurality of nodes which receive the time-synchronization request frame; and performing time-synchronization with one of the plurality of nodes using the time-synchronization information included in the time-synchronization reply frame.

Method and device for time-synchronization in ad hoc network

When stored identifying information of a transmission target frame and identifying information of a received frame are equal, a node apparatus updates transmission feasibility information stored in association with the final destination of the received frame. The transmission feasibility information indicates feasibility of transmission to each of a plurality of adjacent node apparatuses being a transmission destination, and is updated so that feasibility of transmission to the transmission destination associated with the identifying information of the received frame indicates that 'the transmission is infeasible'. The node apparatus transmits the received frame, when there is no adjacent apparatus to which transmission is feasible, and when the stored identifying information of the transmission target frame is equal to the identifying information of the received frame, to the adjacent node apparatus recognized as the origin in association with the identifying information of the received frame.

Node apparatus, storage medium and frame transmitting method

In a node devicein a communication network, an FID management tablestores an FID for unique identification of a frame and the information about a destination node of the frame, and a weighting tablestores weighting information about another node as a destination for relay of the frame for each final destination node of the frame. When a frame transmitted to a local node is received, and if the FID of the received frame is stored in the FID management table, the data about the destination node associated with the FID is updated. If the FID of the frame received from the frame reception device is not stored in the FID management table, the FID management tablecorresponding to the destination node of the frame is referred to, and another node as a destination for relay of the frame is determined.

Node device and computer readable storage medium storing program

A first node apparatus includes: ports; a storage device; and receiving, updating, and transmitting circuits. The storage device stores: information associating, with first identification information identifying a first frame, information distinguishing a first port having been used as a destination port when the first node apparatus has transmitted the first frame; and information associating, with each node apparatus, state information indicating whether frame transmission from each port is feasible. The receiving circuit receives, from a second node apparatus, a second frame including second identification information. When the second identification information is identical with the first, the updating circuit updates the state information associated with a node apparatus being a destination of the second frame to make the state information indicate frame transmission from the first port is not feasible. The transmitting circuit selects a second port from which transmission of the second frame is feasible, and transmits the second frame.

Node apparatus and communication method

A communication apparatus includes an encryption key generation unit that generates encryption key information at constant encryption key generation intervals, a common key generation unit that generates common key information uniquely with respect to a generation time at common key generation intervals set longer than the encryption key generation intervals, a common key application unit that performs encryption or decryption of the encryption key information by using the common key information, and an encryption key distribution unit that makes a request to a data transmitting/receiving unit to distribute the encryption key information to a plurality of communication apparatuses to be communicated simultaneously at encryption key distribution intervals set shorter than the encryption key generation intervals to perform communication with higher security.

Communication apparatus and communication method

A node apparatus changes a first access key unique to itself; changes a shared key same for node apparatuses; encrypts, using the shared key, the first access key and transmits it; receives an access key notification frame; decrypts it using the shared key, thereby obtaining a second access key; attaches, to a first plaintext frame, first signature data obtained by encrypting, using the shared key, data including a first value calculated from the first plaintext frame; encrypts the first plaintext frame using the second access key and transmits thus encrypted frame; receives a second encrypted frame; decrypts it by the first access key to obtain a second plaintext frame; obtains a second value by decrypting, using the shared key, a second signature data attached to the second plaintext frame; calculates a third value from the second plaintext frame; and confirms whether the second and third values are consistent.

Growing community of inventors

Fukuoka, Japan

Syunsuke Koga