Fujitsu Corporation

Taniguchi, Atsuki

Kondo, Ryuichi

Ohtsuka, Tomoyuki

Naitou, Hidetoshi

Atsuki Taniguchi

Kazuo Takatsu

Tomohiro Ishihara

Masahiro Shioda

Takaaki Wakisaka

Haruo Yamashita

Kenji Fukunaga

Takumi Iwai

Takashi Kuwabara

Koji Matsunaga

Junichi Moriyama

Junichi Ishiwatari

Nobuhiro Fujimoto

Tatsuya Toyozumi

Yukio Yamazaki

Shosaku Yamasaki

Tsutomu Chikazawa

Satoshi Takeda

Yumiko Ogata

Ryuichi Kondo

Tomoyuki Ohtsuka

Yoshihisa Ikeda

Takanori Yasui

Chiyoko Yamamoto

Nobuhiko Usui

Masayuki Maehira

Hidetoshi Naitou

Norihisa Miura

The present invention is a technology concerning a reception pointer processing in an SDH transmission system. The objects of the invention are to identify automatically a frame size (frame composition) of the received transmission frame in the SDH (SONET) transmission system and to perform flexibly and rapidly a reception pointer processing corresponding to the frame size. These objects are realized by providing a reception pointer processing apparatus for performing the pointer processing of the transmission frame transmitted by the SDH transmission system, wherein the reception pointer processing apparatus comprises a pointer processing section for executing the required pointer processing of each unit frame contained in the transmission frame, and a frame composition identification section for identifying automatically the frame composition of the transmission frame based on the pointer processing result of the pointer processing section and for providing the identification result to the pointer processing section.

Reception pointer processing apparatus in SDH transmission system

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

In a light transmission equipment which can generate a desired concatenation signal from a maximum concatenation signal standardized in a synchronous transmission mode, a master and a slave circuit for clock change are provided respectively inputting at least two data at a maximum transmission rate based on a concatenation standard of a synchronous transmission mode obtained by dividing a desired transmission rate not prescribed in the concatenation standard to perform a concatenation control to the slave circuit by control information from the master circuit side.

Light transmission equipment

In an error correcting method and an apparatus therefor using Hamming codes, a frame regulated by a synchronous network is divided into L blocks in the direction of row. Preferably, information bits and check bits are allocated to a payload portion and non-defined bits of an LOH portion, respectively. More preferably, the information bits and the check bits are divided into M sub blocks to form a Hamming code block. In addition, a code error correcting means rearrange each Hamming code block per bit and further preferable, a syndrome register with a plurality of banks operates an error syndrome of the Hamming code block, and based on the operation result, the code error correction of the Hamming code block is performed by a bank switchover.

Error correcting method and apparatus

In a transmission method and apparatus, low-speed SDH signals are multiplexed into a high-speed SDH frame, the high-speed SDH frame including at least an information payload, a line overhead and a section overhead, the section overhead being divided into a first section overhead SOH and a second section overhead SOH, the first SOH carrying regenerator SOH bytes and the second SOH carrying multiplex SOH bytes. The multiplex SOH bytes in the second SOH of the high-speed SDH frame are detected without changing the line overhead and the payload when the high-speed SDH frame reaches a receive-side high-level line terminating equipment. The multiplex SOH bytes in the second SOH of the high-speed SDH frame are generated without changing the line overhead and the payload before the high-speed SDH frame is transmitted by a transmit-side high-level line terminating equipment.

Transmission method and apparatus for transmitting low-speed SDH signals using a high-speed SDH frame

The present invention relates to an SDH transmission technique. In an SDH transmission system including a plurality of SDH transmission units for multiplex relay and one SDH transmission unit for relay, with a desired network formed by the respective SDH transmission units, the SDH transmission system is provided with a relay section for a communication carried out between the SDH transmission unit and the SDH transmission unit, or between the SDH transmission units, a multiplexing section for a communication carried out between the transmission units, and a network section for a desired communication carried out irrespective of the multiplexing section and the relay section in the above network. It is thereby possible to freely carry out a desired communication in the network irrespective of the relay section and the multiplexing section which are defined in an SDH transmission mode.

SDH transmission system, and frame transmission method in SDH transmission system and SDH transmission unit

A ring transmission system of a bidirectional line switched ring (BLSR) type comprising nodes (A) to (F) connected by ring transmission lines RL, wherein the nodes (A) to (F) have modified squelch tables &lsqb;A&rsqb; to &lsqb;F&rsqb; and squelch decision units. The ring topology is built by transmitting a ring topology frame and inserting the ID of each node in that frame. Each of the nodes creates a modified squelch table comprised of modified node IDs given to the nodes in a rising order of connection starting from itself using itself as &ldquo;0&rdquo; or another reference value. Whether or not to perform a squelch operation is determined by comparing the magnitude of the modified node IDs of the nodes which signals cannot reach at the time of occurrence of a failure and the modified node IDs in the modified squelch table. This enables the squelch processing to be performed at a high speed.

Ring transmission system and squelch method used for same

Two alarm detecting units required as alarm detecting units for controlling a PSW in order to implement a PSR function, are deleted, and instead the result of an alarm detection output by a conventional alarm detecting unit (E-THRU) for a BLSR function is cross-connected in units of STS-1 frames by an alarm TSA apparatus (E-DROP). In the same way, the result of an alarm detection output by an alarm detecting unit (W-THRU) is cross-connected in units of STS-1 frames by an alarm TSA apparatus(W-DROP). These two cross-connected alarms are compared by a comparing unit (DROP). Based on the result of the comparison the PSW is controlled.

Path switching device for transmission apparatus

In a transmission apparatus in a ring network, provided are a demultiplexing section for demultiplexing multiplexed transmission signals and outputting thus demultiplexed signals; a branching and inserting section adapted to cause, of the demultiplexed transmission signals, a transmission signal of a desired channel to branch out into another line and insert a signal from another line as a transmission signal into the channel from which the transmission signal branches out; and a multiplexing and transmitting section for multiplexing the transmission signals from the branching and inserting section and transmitting thus multiplexed signal as a multiplexed transmission signal to a line which becomes a relaying destination of transmission; wherein the branching and inserting section comprises a transmission route setting mechanism for setting a transmission route of each set of transmission signals such that each set of the transmission signals are transmitted by one of a plurality of kinds of transmission systems, thereby constructing a ring network having a plurality of transmission systems different from each other.

Transmission apparatus in ring network

A ring transmission system of a bi-directional line switched ring (BLSR) type comprising nodes (A) to (F) connected by ring transmission lines RL, wherein the nodes (A) to (F) have modified squelch tables [A] to [F] and squelch decision units. The ring topology is built by transmitting a ring topology frame and inserting the ID of each node in that frame. Each of the nodes creates a modified squelch table comprised of modified node IDs given to the nodes in a rising order of connection starting from itself using itself as '0' or another reference value. Whether or not to perform a squelch operation is determined by comparing the magnitude of the modified node IDs of the nodes which signals cannot reach at the time of occurrence of a failure and the modified node IDs in the modified squelch table. This enables the squelch processing to be performed at a high speed.

A connection switching circuit is disposed in each node of a ring system in which a first ring and a second ring are provided with two communication lines which allow data to flow in a different direction respectively and is connected with a currently used passage and preliminary passage. The connection switching circuit comprises an alarm correction reading part for generating a control signal, an alarm monitor part for outputting respective alarm detection signals, a currently used/and preliminary alarm recognition part, and a switching control signal generation part for generating a control signal for selecting a passage, wherein either the currently used passage or the preliminary passage is selected by monitoring the alarm of the data which flows on the currently used passage or the preliminary passage to connect the first ring and the second ring with each other.

Connection switching circuit for ring system

In a first phase-locked loop, a digital value corresponding to the mean frequency of an input clock signal is obtained. In a second phase-locked loop, the mean value of the phase difference of an output clock relative to the input clock is measured and is added to the digital value corresponding to the mean frequency, to obtain a control value. From this control value, a control signal for uniformly controlling a dual-modulus frequency divider is generated and supplied to the dual-modulus frequency divider. In a moving-average circuit, a selector selects input data when updating the contents of a serial latch circuit array, and selects an output of the serial latch circuit array when accumulating values. Values serially output from the latch circuit array for accumulation are successively added up using an adder and a latch circuit. In a division-ratio equalization circuit, a calculating circuit calculates quotients a.sub.0, a.sub.1, a.sub.2 . . . a.sub.m when the control value is expressed as 1/(a.sub.0 +1/(a.sub.1 +1/(a.sub.2 + . . . +1/a.sub.m)) . . . ), and the quotients are set as division ratios in programmable frequency dividers connected in cascade, through which a reference clock signal is frequency-divided to obtain the control signal.

Phase-locked loop oscillator, and moving-average circuit, and

There is provided a different system transfer method for a ring transmission system and a transmission apparatus for transferring the ring transmission system constructed in the UPSR system to the BLSR system while a line is in service. A control board of the UPSR system is replaced by a control board of the BLSR system. By changing over a path switch, a multiplexing/demultiplexing conversion board of the UPSR system on the non-operating side is replaced by a first multiplexing/demultiplexing conversion board of the BLSR system which is set so as to operate in the UPSR system. Also, by changing over the path switch again, a multiplexing/demultiplexing conversion board of the UPSR system on the non-operating side is replaced by a second multiplexing/demultiplexing conversion board of the BLSR system which is set so as to operate in the UPSR system. Next, the first and second multiplexing/demultiplexing conversion boards are made to operate in the BLSR system, and a line arrangement is changed from the UPSR system to the BLSR system.

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Kawasaki, Japan

Atsuki Taniguchi