Fujitsu Corporation

Kenichi Yajima

Yasuyuki Mitsumori

Tsutomu Chikazawa

Koichi Sugama

Yukio Katayanagi

Ryuji Kayama

Takashi Kaiga

Naoya Okada

Masahiro Shioda

Hideo Abe

Ryuichi Moriya

Tsuyoshi Ohigawa

Noboru Shimizu

A transmission device includes: a code generator configured to generate delay measurement information; an insertion unit configured to sequentially insert the delay measurement information generated by the code generator, in each of delay measurement signals in a plurality of frames, and to sequentially transmit the plurality of frames sequentially inserted with the delay measurement information to a counterpart device on a transmission path whose path delay time is to be measured; and a detector configured to receive a plurality of frames transmitted from the counterpart device and to detect the delay measurement information included in each of delay measurement signals in the plurality of received frames.

Transmission device, transmission network system, and path delay measuring method

There is provided an apparatus for performing loop-free transmission in a communication network. The apparatus includes a plurality of ports, a controller, a memory, and an interface unit. The controller generates monitoring frames that are transmitted to another apparatus, so as to monitor a connection state of the communication network. The memory includes port-state information that stores a port state in association with each of the plurality of ports. The interface unit processes a frame based on the port-state information and sets, in the port-state information, a stopped state to a first port included in the plurality of ports, in accordance with a time period during which the monitoring frames are not generated. The interface unit discards a frame received via the first port for which the stopped state is set in the port-state information.

Apparatus for performing loop-free transmission in a communication network

A transmission device in which a bus of a central processing unit is used to synchronize timing signals between units, thereby restraining enlargement in scale of wiring. A reference signal generator generates a reference signal. A reference signal receiver is mounted on a unit set as an active or standby unit and receives the reference signal. A timing signal generator divides the frequency of the received reference signal by means of a frequency divider/counter to generate a timing signal. A count holder holds the count value of the frequency divider/counter. The bus connects the units and the central processing unit. A count receiver receives, via the bus, the count value from the count holder of the active unit. A count updater updates the count value of the frequency divider/counter to the count value received by the count receiver.

Device for synchronizing between an active unit and a standby unit

In a power supply monitoring device, a power supply voltage monitoring portion always monitors a power supply voltage supplied to a monitored circuit and outputs a voltage reduction signal when detecting that the power supply voltage is reduced below a predetermined threshold (e.g. a second voltage higher than a voltage guaranteeing a normal operation of the monitored circuit and lower than a rated voltage). A monitoring controller having received the voltage reduction signal determines whether or not an operational malfunction has occurred in the monitored circuit by comparing operation data of the monitored circuit with reference data of the monitoring controller itself. Also, the monitoring controller executes recovery processing (reset processing or reference data overwrite processing) suitable for the monitored circuit referring to a prestored recovery processing type specific to the monitored circuit when detecting an operational malfunction of the monitored circuit.

Power supply monitoring device

Growing community of inventors

Kawasaki, Japan

Kenichi Yajima