Fujitsu Corporation

Junichi Moriyama

Takashi Honda

Kanji Naito

Hiroshi Kanzawa

Masaaki Iwasaki

Masahiro Shioda

Atsuki Taniguchi

Katsuhiro Shirai

Fumihiro Ikawa

Kazunari Shiota

Tsutomu Chikazawa

Seiji Meki

Hatsumi Iino

Yoshihisa Ikeda

Isao Takata

Takanori Yasui

Hidetoshi Kawamura

Hisashi Taketomi

Kumiko Uematsu

Yukie Yoshihara

Shunji Yamada

A network connection device for performing a process of transmitting and receiving a SONET/SDH frame includes a first protocol processor which processes a first network management protocol; a second protocol processor which processes a second network management protocol; a frame header extractor which extracts a header from the received SONET/SDH frame; and a protocol identifier which identifies a network management protocol based on the extracted frame header. The network connection device selects one of a control signal outputted from the first protocol processor and a control signal outputted from the second protocol processor based on a result of the identification, and outputs the control signal.

Network connection device and signal processing method in the network connection device

Two multiplexing/demultiplexing sections of working and protection sides are prepared for each of a plurality of optical transmission devices which constitute a system, and the optical transmission devices are synchronized with each other to execute switching between the working and protection sides so that one of the working and protection sides can be selected for the entire system. Each expansion device collects optical line trouble information for each of the working and protection sides, and transmits to a main device. The main device integrates the information with trouble information transmitted from expansion devices per expansion device. The main device converts the integrated trouble information into point information, totals for each of the working and protection sides, compares, and decides which of the working and protection sides is to be selected.

Optical transmission system including a plurality of optical transmission devices

An optical transmission technique for a ring transmission system that can transmit time-division-multiplexed optical signals in dual directions. An optical transmitting apparatus comprises a data link reading section, a topology creating section, a data link writing section, a squelch table creating section, a squelch table, an RIP table creating section, an RIP table, a node recognizing section, an east-side receiving unit, an east-side transmitting unit, a west-side transmitting unit, and a west-side receiving unit. When a transmission route is switched at plural positions, the squelch table and the RIP table are automatically created as soon as a crossconnect is set. With minimum setting, the ring transmission system can be normally operated without increasing the number of setting items, the squelch table can be created at a high speed using existing hardware, and an alarm can be automatically transmitted from a secondary node until each table is created.

Optical ring transmission system using squelch method

A switching method in a bidirectional line switched ring includes the steps of performing span switch by one node of the ring for getting rid of a fault detected by the one node, changing the span switch into ring switch when the span switch could not be performed normally, and performing the ring switch, and holding the ring switch request as an internal request of the one node when a span switch request, higher in priority than the ring switch, generated in another node is received by the one node.

Switching method for bidirectional line switched ring and node apparatus used in the ring

A ring configuring method configures a network in which a plurality of nodes are connected linearly, and performs topology construction for the ring by circulating topology data through the respective nodes and collecting connection information of the respective nodes. The method includes the steps of providing in the topology data a flag indicating whether the connection information is collected in each node; inverting the flag at a terminal station which is an end node of the open ring, and turning the topology data there; causing the topology data to passing through a node other than any terminal station as it is; and adding the connection information to the topology data in each node according to the flag, and performing topology construction.

Ring configuring method and node apparatus used in the ring

A transmission apparatus has units to which main signals are input for subjecting these main signals to predetermined processing and then transmitting them. One of these units is a master unit and the others are slave units and they are interconnected by a clock cable and processor-to-processor cable. Each slave unit detects a synchronization status message that has been inserted into a main signal input from a line and notifies the main unit of this synchronization status message via the processor-to-processor cable. Using synchronization status messages acquired from the slave units and a synchronization status message that has been inserted into a main signal input thereto, the main unit obtains the synchronization status message indicative of the best quality level and adopts, as a master clock, a clock extracted from the main signal into which this synchronization status message has been inserted.

Method of synchronization status message processing in transmission

Disclosed is an optical transmission system for transmitting data via an optical transmission line in accordance with a frame format having overhead which includes a K1 byte used for a switching request and a K2 byte used to respond to the K1 byte. The optical transmission system includes N sets of working terminal stations, one set of protection terminal stations, N-number of optical transmission lines for interconnecting respective ones of the N sets of working terminal stations one optical protection transmission line for interconnecting the one set of protection terminal stations, repeater stations, which are provided in the optical transmission lines between the N sets of working terminal stations, for demultiplexing and outputting data extracted from the transmission lines or for multiplexing data and inserting the data in the transmission lines, protection transmission line connecting units, which are provided at positions in a protection transmission line corresponding to positions at which the repeater stations are disposed, for switching a failed transmission line to the protection transmission line in every section demarcated by the repeater stations. A working terminal station or repeater station that has detected occurrence of failure in a transmission line of a prescribed section sends K1 byte to and receives K2 byte from an opposing working terminal station or repeater station of the section via a protection terminal station or protection transmission line connecting unit and switches the failed transmission line section to the protection transmission line.

Optical transmission system and transmission line switching control

A communication port control system which controls the use of communication ports for making a communication between a main station and a plurality of sub stations, and includes a processing unit for processing data received from the sub stations, and a logical sum unit for obtaining a logical sum of the data received from the sub stations and for supplying the logical sum to the processing unit via the communication ports. A judging unit is provided in the control system for judging a sub station number of the sub station from which the data received by the logical sum unit originates and for supplying the sub station number to the processing unit. The logical sum unit receives the data from only one of the sub stations at one time.

Communication port control system

Optical transmission system

A line terminal equipment provided in a drop-insert station of a transmission system for receiving a signal from a preceding station of the drop-insert station through a preceding protection line is electrically connected in a protection switching equipment provided in the drop-insert station, to a line terminal equipment provided in the drop-insert station for transmitting the signal to a succeeding station of the drop-insert station, by a connecting line provided in the protection switching equipment, in any one of cases where no disconnection trouble occurs on preceding and succeeding work lines, where disconnection troubles occur on one of the preceding work lines and a succeeding work line associated with the preceding work line and where a disconnection trouble occurs on one of the preceding work lines. The connecting line is disconnected in a case where a disconnection trouble occurs on one of the succeeding work line.

Signal branching method applied to a protection switching equipment

Disclosed is a password security method in a man-machine system for keeping the secrecy of a password during a setting process of the system. To keep not only the secret of the password but also the presence of the password from unauthorized users, the method comprises a prompt displaying step for prompting to enter an equipment name and not prompting to enter the password; a password discriminating step to discriminate whether or not a correct password is entered; a step for entering a normal mode when the correct password is not detected; and step for entering a password mode when the correct password is detected.

Password security method

An initial status setting system in a multi-unit system constructed of a plurality of units wherein at least a set of status data is held in registers in at least two of the plurality of units, both units indicating whether or not the set of status data held in each of the registers is valid. The output of each of the registers is applied to the other of the registers, and each of the registers is controlled so that only a valid set of status data is input thereto.

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Kawasaki, Japan

Junichi Moriyama