Abstract: A method for virtualizing an optical network, comprising: abstracting optical resource information corresponding to resources within the optical network, constructing a plurality of candidate paths for one or more optical reachability graph (ORG) node pairs, determining whether the candidate paths are optical reachable paths, and creating an ORG link between each ORG node pair when at least one optical reachable path exists for the ORG node pair, wherein linking the ORG node pairs creates an ORG. In another embodiment, a computer program product comprising executable instructions when executed by a processor causes a node to perform the following: determine an optical network's optical-electrical-optical (OEO) conversion capability, partition a plurality of service sites into one or more electrical reachability graph (ERG) nodes, determine a grooming capability for each ERG node, and construct a plurality of electrical-layer reach paths between the ERG nodes to form an ERG.

Abstract: Embodiments of the present invention provide a method and a device for allocating a packet switching resource, which includes: receiving, by a management plane unit, a service transport request carrying service information, where the service information includes source node information, sink node information, quality of service QoS requirement information, and bandwidth requirement information; determining, by the management plane unit, at least one transport path according to the service information and a preset resource allocation policy, and generating a routing table entry/forwarding table entry according to the at least one transport path; and sending, by the management plane unit, the routing table entry/forwarding table entry to data plane units of packet switching devices of each transport path of the at least one transport path.

Abstract: A method for virtualizing an optical network, comprising: abstracting optical resource information corresponding to resources within the optical network, constructing a plurality of candidate paths for one or more optical reachability graph (ORG) node pairs, determining whether the candidate paths are optical reachable paths, and creating an ORG link between each ORG node pair when at least one optical reachable path exists for the ORG node pair, wherein linking the ORG node pairs creates an ORG. In another embodiment, a computer program product comprising executable instructions when executed by a processor causes a node to perform the following: determine an optical network's optical-electrical-optical (OEO) conversion capability, partition a plurality of service sites into one or more electrical reachability graph (ERG) nodes, determine a grooming capability for each ERG node, and construct a plurality of electrical-layer reach paths between the ERG nodes to form an ERG.

Abstract: A method for virtualizing an optical network, comprising: abstracting optical resource information corresponding to resources within the optical network, constructing a plurality of candidate paths for one or more optical reachability graph (ORG) node pairs, determining whether the candidate paths are optical reachable paths, and creating an ORG link between each ORG node pair when at least one optical reachable path exists for the ORG node pair, wherein linking the ORG node pairs creates an ORG. In another embodiment, a computer program product comprising executable instructions when executed by a processor causes a node to perform the following: determine an optical network's optical-electrical-optical (OEO) conversion capability, partition a plurality of service sites into one or more electrical reachability graph (ERG) nodes, determine a grooming capability for each ERG node, and construct a plurality of electrical-layer reach paths between the ERG nodes to form an ERG.

Abstract: 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.

Abstract: Embodiments of the present invention provide a method and a device for allocating a packet switching resource, which includes: receiving, by a management plane unit, a service transport request carrying service information, where the service information includes source node information, sink node information, quality of service QoS requirement information, and bandwidth requirement information; determining, by the management plane unit, at least one transport path according to the service information and a preset resource allocation policy, and generating a routing table entry/forwarding table entry according to the at least one transport path; and sending, by the management plane unit, the routing table entry/forwarding table entry to data plane units of packet switching devices of each transport path of the at least one transport path.

Abstract: A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.

Abstract: 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.

Abstract: A method for virtualizing an optical network, comprising: abstracting optical resource information corresponding to resources within the optical network, constructing a plurality of candidate paths for one or more optical reachability graph (ORG) node pairs, determining whether the candidate paths are optical reachable paths, and creating an ORG link between each ORG node pair when at least one optical reachable path exists for the ORG node pair, wherein linking the ORG node pairs creates an ORG. In another embodiment, a computer program product comprising executable instructions when executed by a processor causes a node to perform the following: determine an optical network's optical-electrical-optical (OEO) conversion capability, partition a plurality of service sites into one or more electrical reachability graph (ERG) nodes, determine a grooming capability for each ERG node, and construct a plurality of electrical-layer reach paths between the ERG nodes to form an ERG.

Abstract: 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.

Abstract: A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.

Abstract: A method for handling a fiber line fault is provided. The method includes: loading, by a station, an indication signal carrying alarm suppression information onto an optical signal to be output to a downstream fiber of the station upon detection of a fault on upstream fiber line; keeping in a normal working status, by a downstream station upon a receipt of the optical signal with the indication signal. The various embodiments of the present disclosure suppress alarms from downstream amplifier stations which are not adjacent to the failure link and further suppress APR or APSD procedures according to the alarms.

Abstract: A method and apparatus for loading, detecting, and monitoring channel-associated signals are provided. Channel-associated signals are identified with spread spectrum codes in the electrical domain, and after being modulated to an optical service signal at respective loading points separately, the channel-associated identification signals are transmitted in the optical channel along with the optical signal. At any downstream detecting point, passing optical signals can be converted through photoelectric conversion, and the channel-associated identification signals are de-spread. By detecting the channel-associated signals, it is possible to learn about whether the upstream loading point work normally, whether the optical channel operates normally, etc., and thereby to find possible failures, solve problems, and monitor quality parameters of optical signals in real time, and improve reliability of the optical signal transmission.

Abstract: The present invention discloses a method and system for group optical channel shared protection. In the invention, when a failure occurs, operations are performed on an optical wavelength group, and four actions are accomplished at the time of switching: switching the affected optical wavelength group on the working fiber to a backup fiber (Steer); switching the optical wavelength group whose destination node is the current node on the backup fiber to the working fiber (Copy); making the optical wavelength group whose destination node is not the current node on the backup fiber transparently pass through the current node (Pass Through); and blocking or stripping the backup wavelength group transferred on the backup fiber (Strip). In addition, the invention further discloses a plurality of node structures for realizing the above operations.

Abstract: Methods and apparatuses for automatic restoration detection and automatic restoration of optical communication system are disclosed. In the methods, a first station sends an automatic restoration detection message to a second station at the opposite side of a failed link; in response to receiving an automatic restoration request message, determines that the link has been repaired in two directions, and sends an automatic restoration confirmation message to the second station; or in response to receiving the automatic restoration detection message, determines that the link from the second station to the first station has been repaired, and sends the automatic restoration request message to the second station; in response to receiving the automatic restoration confirmation message, determines that the link has been repaired in two directions; and switching to normal working states. The safety problem that the laser leakage occurs in the failed link is solved.

Abstract: A method for laser safety protection in an optical communication system includes: a downstream station detecting whether an identification signal loaded by an upstream station on a main optical channel in a direction from the upstream station to the downstream station, exist on the main optical channel; if the identification signal is not detected, the downstream station executing a scheduled safety protection procedure. Methods for loading an identification signal on a main optical channel in an optical communication system and an optical amplifier of laser safety protection, which implement loading the identification signal by controlling the change of pump light of optical amplifier or the wave motion of signal light of main optical channel, are also provided. The solution makes it possible to reliably detect a fiber failure when RAMAN amplifiers or remotely-pumped amplifiers exist, thereby implementing laser safety protection.

Abstract: The present invention discloses a method and device for implementing Och-SPRing in Wavelength Division Multiplexing system. The method includes: in the node of the optical network system, setting two switches in each working path and its backup path that pass through the node, each of which includes two input ports and one output port; when receiving signals, controlling the first switch to selectively accept the downlink service signals sent from the working path or the backup path; when sending signals, sending the uplink service signal sent from the local device respectively to one output port of uplink direction in the working path and the second switch; controlling the second switch to choose one signal among the local uplink service signal and the downlink service signal sent from the backup path to input into the uplink direction of the backup path. The method of the present invention can largely reduce construction cost of the system, save optical power budget, and improve OSNR.

Abstract: 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.

Abstract: The present invention relates to network transmission technologies, and provide a Generic Framing Procedure (GFP)-based add/drop multiplexing (add/drop multiplexing) method, apparatus and system to improve add/drop multiplexing utilization, in which multiple Gigabyte Ethernet (GE) connections among multiple nodes are multiplexed in GFP to a byte synchronous interface for transmission, wherein a bandwidth of the byte synchronous interface is smaller than a sum of peak bandwidths of the group of GE connections borne on the byte synchronous interface; statistical multiplexing is carried out on effective data borne on the multiple GEs by means of buffers, and the effective data are treated by priority in the case of network congestion. The present invention implements statistical add/drop multiplexing for multiple data services in various types, and can be used in implementing a statistical ADM for diverse data services in burst mode, even a statistical ADM for multiple mixed services.

Abstract: A method for handling a fiber line fault is provided. The method includes: loading, by a station, an indication signal carrying alarm suppression information onto an optical signal to be output to a downstream fiber of the station upon detection of a fault on upstream fiber line; keeping in a normal working status, by a downstream station upon a receipt of the optical signal with the indication signal. The various embodiments of the present disclosure suppress alarms from downstream amplifier stations which are not adjacent to the failure link and further suppress APR or APSD procedures according to the alarms.