Nec Corporation

Shinobu Sasaki

Takashi Yamazaki

Naoya Henmi

Shinya Nakamura

Hitoshi Takeshita

Motoo Nishihara

Kazuo Takagi

Tatsuya Shiragaki

Yuuki Yoshifuji

Naoki Ando

Kurenai Murakami

Shuichi Iida

Kimio Ozawa

Minoru Shinta

Hitoshi Kikuchi

Youko Nakabayashi

Ryou Yamada

Mitsuru Kawabata

Yoshinori Rokugou

Hiromitu Watanabe

Tukasa Haga

A storage circuit defines a first field for storing first header bits of a first payload signal of a first data unit, a second field, and a third field for storing the first payload signal. The first header bits are equal in number to second header bits of a second payload signal of a second data unit. A division circuit divides the first header bits by a generator polynomial to produce a first error check code. The same generator polynomial is used to divide the second header bits to produce a second error check code. A remainder of division of hypothetical header bits by the generator polynomial is summed to the first error check code to produce a sum which is inserted into the second field of the storage circuit. The hypothetical header bits are greater in number than a total number of bits in the first and second fields, so that the first and second data units can be distinguished from each other by different error check results of the first and second data units.

Method and system for transmission and reception of asynchronously multiplexed signals

Disclosed is a WDM network which has: a lightwave path which connects between clients and each of which is provided with an overhead, and a sub-network which is defined by dividing the WDM network. In this WDM network, the sub-network has a partial lightwave path to go through the sub-network, the overhead has a partial lightwave path supervisory control information region which is terminated at both nodes of the partial lightwave path, and when a fault occurs on a lightwave path, the fault information of partial lightwave path including the position information of fault occurred is added to the partial lightwave path supervisory control information region of the overhead.

WDM network and WDM network device

An optical ring system having: a wavelength demultiplexer to which wavelength-multiplexed optical signal to be sent through an optical fiber from a previous node of multiple nodes is input and in which optical signal with each wavelength assigned to itself is demultiplexed; an optical ring device which is disposed in a predetermined node of the multiple nodes to the each wavelength assigned and which is composed of a failure existence judging part which terminates an overhead of each optical signal with a wavelength demultiplexed by the wavelength demultiplexer and judges whether a failure occurs in regard to a wavelength in a previous section through which optical signal with the assigned wavelength is sent, and a switching part which, when the failure existence judging means determines the occurrence of failure, selects a path that allows optical signal with the wavelength to be transmitted to the previous node while avoiding the previous section incurring the failure; and a wavelength multiplexer which multiplexes optical signal to be output from the optical ring part and then outputs it to an optical fiber connected to a next node.

Optical ring system

The present invention provides a VP protection system and a VP protection method which forward messages quickly to nodes on an ATM network when an error occurs on the ATM network and reduce an error recovery time. The VP protection system, for use on an ATM network that includes a plurality of ATM nodes performing protection, a plurality of working VPs, and a plurality of standby VPs, exchanges messages among ATM nodes when an error occurs, one group of VPs at a time. An intermediate ATM node in a standby path at least comprises a VPG resource information management table, a VP resource information management table, a VPG configuration information management table, a VPG switching message receiving circuit, a VPG switching message sending circuit, node resource management circuits, a VPG resource allocation circuit, a VP expansion circuit, and a VP resource distribution circuit.

VP protection system and VP protection method

Growing community of inventors

Tokyo, Japan

Shinobu Sasaki