Nippon Telegraph and Telephone Corporation

Yoshihiko Uematsu

Shinji Matsuoka

Masahito Tomizawa

Hiroki Kawahara

Katsuhiro Araya

Toshiyuki Oka

Hiroshi Yamamoto

Yoshiaki Yamabayashi

Shigeru Teruhi

Hidetoshi Mori

Nobuyuki Kawase

When separate service apparatuses that provide various communication services to users are connected by a wiring with communication functional units interposed, if there is a wiring abnormality, the location of the abnormality is easily identified. When a wiring connection is completed between separated service apparatuses X and Y that provide various communication services to user terminalsandwith communication functional units Aand Binterposed, a wiring management systemA includes a transmission network management apparatusA that identifies a wiring abnormality. The transmission network management apparatusA associates endpoint names of the service apparatuses X and Y and of the functional units Aand Bwith opposite endpoint names on the opposite sides, defines opposite endpoint IDs of the endpoints of the functional units Aand Bas expected values, and saves the end points in association with the opposite endpoint IDs in a DB. Upon completing the wiring connection between the service apparatuses X and Y, an opposite endpoint ID of each of the functional units Aand Band the service apparatuses X and Y opposite to predetermined functional units Aand Bis received as a received value via a wiring, and if the received value does not match the expected value, it is determined that the wiring is abnormal.

Wiring management system and wiring management method

[PROBLEM TO BE SOLVED] To uninterruptedly change a band of an optical transmission path in a line IF section, which relays a signal transmitted to an optical transmission path in a client IF section to which a communication terminal is connected, to the same band as a changed band in the client IF section without suspending the communication in the line IF section. [SOLUTION] An optical transmission systemA performs processing for changing a band of an optical fiberin a line IF section (L section) that relays a signal from an optical fiberin a client IF section (C section) to the same band as that in the C section. Line IF unitsA andB provided on both sides of the L section set a temporary evacuation lane p as an optical lane having a band different from those of a plurality of optical lanesto n in the optical fiberin the L section, selects either a change-target optical lane (for example, the optical lane) or the temporary evacuation lane p, the change-target optical lane being provided in the optical fiberin the L section and having a band to be changed to a same band as a band in the C section, while causing a buffer unitto absorb a delay difference between a signal received by the change-target optical lane and a signal received by the temporary evacuation lane p, and sets the optical lane not selected to have the same band as the band in the C section.

Optical transmission system and optical transmission method

[Problem] It is possible to cancel out beat noises in a WDM signal to obtain a high-quality signal component, and a configuration thereof is achieved with low mounting costs. [Solution] An optical reception device converts a WDM signal rs(t) of an optical signal to electrical signals d(t)to d(t)n expressed as complex numbers of orthogonal phases, cancels out beat noises from the electrical signals, and then demodulates the signals to obtain signals Dto Dn of a transmission source. This optical reception device includes an absolute value calculation unitstothat generate a signal component including a beat noise component through absolute value squaring calculation processing for squaring an absolute value of the electrical signal, scaling unitstothat multiply the generated beat noise component by a proportional constant to restore beat noise associated with n types of wavelengths in the electrical signal, and subtraction unitstothat subtract the n type of beat noises restored from the electrical signal to cancel out then types of beat noises included in the electrical signal.

Optical reception device

A source nodeobtains from a destination nodequality information on routesandto the node, and adaptively changes data distribution ratios for the multiple routes based on the quality information.

Data transmission control method, program therefor and data transmission unit using the same

In a trunk transmission network for transmitting information signals between nodes via paths, flexible path operation is achieved by setting up paths between source nodes and destination nodes after pre-classifying paths into a higher service class in which any loss of information occurring in that path is made good restored; and a lower service class which permits loss of information to occur in the path. The flexible operation is further achieved by arranging for each node, when it acts as a source node, to recognize the service class of the information signal it is sending to a destination node, and to select a path corresponding to that service class.

Trunk transmission network

In a trunk transmission network for transmitting information signals between nodes via paths, flexible path operation is achieved by setting up paths between source nodes and destination nodes after pre-classifying paths into a higher service class in which any loss of information occurring in that path is restored, and a lower service class which permits loss of information to occur in the path. The flexible operation is further achieved by arranging for each node, when it acts as a source node, to recognize the service class of the information signal it is sending to a destination node, and to select a path corresponding to that service class.

The invention has the object of offering a channel-selection-type demultiplexing circuit which is capable of interchanging the time slots of demultiplexed signals when demultiplexing ultra-high-speed multi-channel multiplexed signal stream without expanding the scale of the circuits, and does not require the scale of the circuits to be expanded even if the speed of the transmission path increases. The invention is a channel-selection-type demultiplexing circuit capable of demultiplexing signals to a desired output port during bit demultiplexing, instead of simply demultiplexing the bits as in conventional devices, which performs bit demultiplexing based on a frequency division clock after selecting the bit signals to be demultiplexed to the desired output port from the N-channel multiplexed signal stream based on channel selection information.

Channel-selection-type demultiplexing circuit

A pointer processor for use in an SDH/SONET transmission system, realizing a proper VC path management. A pointer interpreter constantly monitors 3X pairs of H1 and H2 bytes to contain a prescribed maximum size pointer AU-4-Xc that can possibly be received by the pointer processor, to obtain and hold an inside AU-size map indicating an occupation state of AU pointers on 3X pairs of H1 and H2 bytes, while generating and holding an assigned AU-size map indicating an assigned state of AU pointers on 3X pairs of H1 and H2 bytes according to an externally set AU pointer size, and compares these two AU-size maps. For a part of map where the inside AU-size map coincides with the assigned AU-size map, the pointer interpreter carries out size-fixed pointer interpretations in pointer sizes specified by the assigned AU-size map, and the pointer generator generates transmission pointers in forms of normal pointers or AISs in the pointer sizes specified by the assigned AU-size map according to the size-fixed pointer interpretations. For a part of map where the inside AU-size map does not coincide with the assigned AU-size map, the pointer generator generates AISs in the pointer sizes specified by the assigned AU-size map as the transmission pointers.

Pointer processor and pointer processing scheme for SDH/SONET

A hitless path switching method without a bit loss. The same digital line signals on a working path and a protection path are continuously monitored independently for bit errors. If a bit error occurs in the working path and no bit error occurs in the protection path, a switching trigger is produced and a switching operation from the working path to the protection path is performed on a data block basis. Only correct data are transferred to downstream apparatuses. Reliable hitless switching is achieved not only in response to a failure in a path, but also in response to a bit error. Using data blocks of one frame length with an indicator for bit error checking placed at its beginning or top makes effective switching possible.

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Tokyo, Japan

Yoshihiko Uematsu