Fujitsu Corporation

Ritsuko Isonuma

Hideaki Mochizuki

A received path trace detection apparatus includes (i) a specific byte extracting/holding function unit for receiving a path signal and extracting and holding once path information written for showing the path in specific bytes in the received path signal at a predetermined sampling timing, (ii) a comparing function unit for detecting if path information for specific bytes held and path specific bytes currently received match, (iii) a protecting function unit for detecting that the matches have continued for exactly a predetermined number of protection stages as a result of the comparison by the function unit, and (iv) a forwarding function unit for forwarding the held path information to an erroneous connection decision unit for deciding if values exhibited by path information of the specific bytes held at the function unit and predetermined expected values match when matches of the consecutive number of protection stages are detected by the function unit.

Received path trace detection apparatus

A transmission device which cross connects channels on a synchronous multiplex transmission network which forms a ring, and which performs restoration of communication by looping back signals in a protection path when a failure occurs includes a memory area which stores information for determining whether an alarm indication signal needs to be inserted in a channel or not, wherein the size of the memory area corresponds to the number of channels targeted for the restoration, and a part which inserts said alarm indication signal in a channel by switching results of the determination according to predetermined information. Further, the transmission device may switch and recover a path without skipping an event which arises between polling accesses by a CPU of said transmission device. Furthermore, the transmission device may include a part, provided in each interface part, which performs phase adjusting of channel signals.

Transmission device

A transmitting apparatus for cross connecting and transmitting main signals which enter via ring-configured transmission lines to which working and protection channels have been assigned in first and second directions, and rescuing a main signal by looping back the main signal in the opposite direction using the protection channel when a transmission line fails. Storing non-rescue information which indicates whether each channel that is the object of rescue by loop-back is a non-rescue channel. Determining whether a failure for which rescue is impossible has occurred in each channel, which is the object of rescue, other than a non-rescue channel. On the basis of main-signal cross-connect information, interchanging a result of discrimination of each channel and inserting the interchanged result of discrimination in the main signal of the corresponding channel after cross connect.

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Kawasaki, Japan

Ritsuko Isonuma