Huawei Technologies Co., Limited

Jianmei Zhang

Congqi Li

Tianhai Chang

Lei Zhang

Zhiyong Huang

Yue Liu

Xinyu Shen

Da He

Zhiguo Liu

Zhiwen Chang

Yuzhi Jin

Shixing Li

Shouchang Niu

Jinghua Song

The present disclosure discloses a time synchronization method. In the method, a first node sends a first time packet at a first time over a first working wavelength; a second node receives the first time packet at a second time. The first node sends a second time packet at a third time over a second working wavelength. The second node receives the second time packet at a fourth time; calculates an absolute time deviation between the second node and the first node according to the first time, the second time, the third time, the fourth time, a first signal transmission rate corresponding to the first working wavelength, and a second signal transmission rate corresponding to the second working wavelength, and synchronizes the local time between the second node and the first node. Further, a time synchronization system and a node device are disclosed.

Time synchronization method and system, and node device

A method and a device for time synchronization are disclosed according to the embodiments of the present invention. The method includes: selecting, by a slave device, a port of a single-fiber bi-directional line as a synchronization port of a 1588 clock protocol; specifying a work mode of the synchronization port; exchanging a 1588 clock synchronization packet with a master device through the synchronization port according to the work mode; acquiring transmission time information and restore a system clock according to the 1588 clock synchronization packet; and adjusting the system clock according to the work mode and the transmission time information. The device includes: a line processing module, a clock recovery module and a clock adjustment module. Through the method and the device, zero-error time synchronization is implemented; and in the case of unfixed path delay, the time synchronization can also be implemented.

Method and device for time synchronization

An upgrading method, a system, and an apparatus of a low-density wavelength division multiplexing (WDM) system are provided. The method includes: detecting an output wavelength shift of a wavelength conversion unit, and adjusting an output wavelength of the wavelength conversion unit having the output wavelength shift higher than a threshold, so that the output wavelength shift of the wavelength conversion unit is lower than the threshold; adjusting an adjustable interleaved demultiplexer, until requirements for a demultiplexing parameter of a high-density WDM system are met. Thus, the problem that services are interrupted when a low-density MDM system is upgraded to a high-density MDM system is solved. A WDM system, and a wavelength multiplexing/demultiplexing apparatus and method are also provided.

Upgrading method, system and apparatus of low-density wavelength division multiplexing system

A method for automatically implementing Tandem Concatenation Monitoring (TCM), includes: requesting a network management system for a required number of TCM levels; assigning an available TCM level to a pair of network nodes in a sub-network; performing TCM processing, mapping TCM use information into a corresponding overhead, transferring the TCM use information together with TCM overhead information downstream, and reporting TCM information to the network management system; and extracting TCM monitored information, determining transmission quality of each sub-network of a set of sub-networks, and locating a network failure. The invention also presents a device for automatically implementing TCM, including a controller, a TCM generator and a TCM terminator which cooperate with each other to automatically implementing a TCM function. The invention addresses the poor flexibility and complexity due to a static configuration by the network management system, and thus improves the flexibility of the TCM processing.

Method for implementing tandem concatenation monitoring automatically and apparatus thereof

The present invention discloses a method and a system for transparent transport of optical channel transmission unit (OTU) signals via an optical transport network (OTN), which includes a transmitting unit and a receiving unit at the OTN network boundary: the transmitting unit converts an OTUj signal mapping entering the OTN network into OTUk signals of the current OTN network for transmission. In the mean time, it reserves the OTUj control overhead, or extracts the OTUj control overhead and transfers it to the reserved overhead location; the receiving unit receives the OTUk signals arriving at the OTN network boundary, and performs demapping and converting them into OTUj signals. In the mean time, it successively uses the aforementioned reserved OTUj control overhead, or extracts the aforementioned OTUj control overhead from the aforementioned reserved control overhead location for subsequent use, and transfers the OTUj signals from the current OTN network; the aforementioned j and k represent the rate rank of the aforementioned OTU, respectively. The present invention is capable of achieving total transparent transport of OTU signals, including a payload portion and a control overhead.

Method and system for transparent transport of optical channel transmission unit signals via an optical transport network

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Shenzhen, China

Jianmei Zhang