41 results about "Wavelength switched optical network" patented technology

Routing and bandwidth assignment of new paths of different bandwidths, occupying different numbers of adjacent frequency slots in a wavelength switched optical network, involves selecting a route, and assigning a set of adjacent frequency slots. The assignment can place wider bandwidth ones of the new paths at an opposite end of a spectrum of the available frequency slots, to an end where narrower bandwidth ones are placed. A size of sets of available adjacent slots remaining after the assignment is likely to be increased, compared to a conventional first fit assignment. A wider subsequent new path can sometimes be accommodated along all or some of the route and thus the blocking probability can be lowered. The selecting of which of the possible routes to use can be made dependent on which has more sets of available adjacent frequency slots, or which has a wider gap between occupied slots.

An apparatus comprising a path computation element (PCE) configured to perform a path computation using signal compatibility constraints information for a network element (NE) in a wavelength switched optical network (WSON), wherein the signal constraints information are communicated at a Generalized Multi-Protocol Label Switching (GMPLS) control plane layer and comprise a plurality of signal attributes and a plurality of NE compatibility constraints. A network component comprising a transmitter unit configured to transmit signal compatibility constraints via GMPLS signaling, wherein the signal compatibility constraints define the signal compatibility constraints for a NE in a WSON. A method comprising receiving signal compatibility constraints for a NE in a WSON, performing a path calculation based on the signal compatibility constraints for the NE, and sending signal compatibility constraints associated with a computed path.

The invention provides a method and a device for optimizing dynamic transmission performance in a wavelength switched optical network. The method comprises the following steps of: making the optical signal-to-noise ratio cost of a dispersion-optimized optical path and the accumulative nonlinear phase shift have a one-to-one correspondence relationship by carrying out pre-dispersion compensation and post-dispersion compensation on source and destination nodes of an optical path; then, obtaining the optical signal-to-noise ratio cost of the optical path, using the power regulating quantity of a power-regulating point as a variable, by using the correspondence relationship, further setting a target function according to the optical signal-to-noise ratio cost and the optical signal-to-noise ratio of the optical path, and optimizing according to a predetermined optimization target and constraint conditions to obtain a node needing power regulation and the power regulating quantity of the same. According to the invention, the transmission performance of the optical path can be improved, and the blockage of physical layers, caused by the substandard physical transmission performance, is avoided.

The invention relates to an encoding method and a processing method of wavelength labels and nodes for a flexible grid optical network. The processing method of the wavelength labels includes that the nodes of the flexible grid optical network receive information carrying wavelength labels including grid capacity identifications corresponding to the wavelength labels and specific parameters of the wavelength labels; the nodes of the flexible grid optical network analyze the specific parameters of the wavelength labels according to the grid capacity identifications; and the nodes of the flexible grid optical network determine a center frequency and / or a spectral bandwidth of wavelength resources according to the analyzed specific parameters of the wavelength labels. According to the encoding method, the processing method and the nodes, flooding of flexible grid routing information and distribution of frequency spectrum resources in an establishing process of signaling of a label switch path (LSP) in a wavelength switched optical network (WSON) can be achieved from a control plane perspective.

An apparatus comprising a path computation element (PCE) configured for at least partial impairment aware routing and wavelength assignment (RWA) and to communicate with a path computation client (PCC) based on a PCE protocol (PCEP) that supports path routing, wavelength assignment (WA), and impairment validation (IV). The PCEP comprises at least one operation selected from the group consisting of a new RWA path request operation and a path re-optimization request operation. Also disclosed is a network component comprising at least one processor configured to implement a method comprising establishing a PCEP session with a PCC, receiving path computation information comprising RWA information and constraints from the PCC, and establishing impairment aware RWA (IA-RWA) based on the path computation information and a private impairment information for a vendor's equipment.

An apparatus comprising a path computation element (PCE) configured for at least partial impairment aware routing and wavelength assignment (RWA) and to communicate with a path computation client (PCC) based on a PCE protocol (PCEP) that supports path routing, wavelength assignment (WA), and impairment validation (IV). Also disclosed is a network component comprising at least one processor configured to implement a method comprising establishing a PCEP session with a PCC, receiving path computation information comprising RWA information and constraints from the PCC, establishing impairment aware RWA (IA-RWA) based on the path computation information and a private impairment information for a vendor's equipment, and sending a path and an assigned wavelength based on the IA-RWA to the PCC. Disclosed is a method comprising establishing impairment aware routing and wavelength assignment for a plurality of network elements (NEs) in an optical network using routing and combined WA and IV.

Dynamic restoration involves routing and bandwidth assignment of an unplanned restoration path in a wavelength switched optical network (20), having regeneration nodes (60), nodes each having a ROADM (62) having drop paths and add paths. An electrical switch (68) provides configurable regeneration capacity by coupling selected drop paths to selected add paths. Some of the configurable regeneration capacity is kept for unplanned restoration paths. A PCE determines (120) routing and bandwidth assignments for an unplanned restoration path for the traffic flow to avoid a fault, and sends (130) configuration messages to the nodes to set up the unplanned restoration path dynamically and to configure the electrical switch to provide regeneration on the path. Keeping some reconfigurable regeneration capacity enables much longer unplanned paths to be found to avoid faults, and enables wavelength conversion if needed. Thus the reliability of finding at least one path avoiding the fault can be increased.

The invention provides a wavelength resource encoding method, a wavelength resource processing method and a node for a flexible grid optical network. The encoding method is characterized in that parameters expressing a wavelength resource comprise position information of a center frequency in a frequency spectrum, information of the bandwidth size of the resource and grid capacity information; and the grid capacity information expresses that the wavelength resource is a flexible grid or a fixed grid. After the scheme of the invention is adopted, by expanding a wavelength label and introducing a new bandwidth object, the encoding and processing methods are suitable for the flexible grid network, so that from the point of a control plane, flooding of flexible grid routing information in the wavelength switched optical network and distribution of spectrum resources in the process that a signaling establish an LSP (Label Switched Path) can be implemented.

The invention discloses a method and a device for acquiring the routing information of an electro-optical multi-layer network. The method comprises the following steps of: determining ports in which an optical transmitter and an optical receiver are positioned; and adding electro-optical conversion information into the routing information on the ports, in which the optical transmitter and the optical receiver are positioned, on an optical layer node side or an electrical layer node side, wherein the electro-optical conversion information comprises, but not limited to, wavelength tuning capacity and signal processing capacity. The invention has the advantages that: by expanding information models of the conventional multi-layer network (MLN) and a wavelength switched optical network (WSON), the routing information which comprises the electro-optical conversion information is more accurately described, and the information model of the electro-optical multi-layer network is perfected, so the accuracy of path calculation is improved, and the path calculation is optimized.

The invention discloses WSON (Wavelength Switch Optical Node) route acquisition method and device, wherein the method comprises the following steps of: acquiring an exit-direction route of a current node from a route section information base; judging whether a destination node pointed to by the exit-direction route is a destination node of an route to be acquired or not; if not, recording a route section between the current node and the destination node to be a route section of the route to be required and setting the pointed destination node to be the current node, and then repeating those steps; if so, recording the route section between the current node and the destination node to be a route section of the route to be required and saving the route to be required. According to the invention, the problem that the routes of WSON nodes can not be required in the prior art and all routes between a source one-board and a destination one-board can also be acquired.

Routing and bandwidth assignment of new paths of different bandwidths, occupying different numbers of adjacent frequency slots in a wavelength switched optical network (20), involves selecting (100) a route, and assigning (110, 120) a set of adjacent frequency slots. The assignment can place wider ones of the new paths at an opposite end of a spectrum of the available frequency slots, to an end where narrower ones are placed. A size of sets of available adjacent slots remaining after the assignment is likely to be increased, compared to a conventional first fit assignment. A wider subsequent new path can sometimes be accommodated along all or some of the route and thus the blocking probability can be lowered. The selecting of which of the possible routes to use can be made dependent on which has more sets of available adjacent frequency slots, or which has a wider gap between occupied slots.

The disclosure includes an apparatus comprising a path computation element (PCE) that manages the processes of routing in an optical network, wherein the PCE receives a path computation request and provides a wavelength range to a network element (NE), and wherein the NE assigns a wavelength from the wavelength range. Also disclosed is an apparatus comprising a path computation client (PCC) that sends a path computation request to a path computation client (PCE) using path computation element communication protocol (PCEP), and receives a routing and wavelength assignment (RWA) reply to the path computation request using PCEP, wherein the RWA reply comprises an PCEP error message comprising a PCEP error object and an error value to indicate errors associated with the RWA request.

The invention provides a multi-wavelength passive optical network system. The multi-wavelength passive optical network system comprises an optical line terminal, an optical distribution network and a plurality of optical network units, wherein the optical line terminal is connected to the optical network units in the mode that one point is connected to multiple points through the optical distribution network. According to the multi-wavelength passive optical network system, the optical network units are divided into a plurality of groups, each group of the optical network units adopts a specific uplink wavelength and a specific downlink wavelength, the optical distribution network comprises a first-level optical splitter and a plurality of second-level optical splitters, the public port of the first-level optical splitter is connected to the optical line terminal through a main optical fiber, the branch ports of the first-level optical splitter are connected with branch optical fibers respectively and are connected to one group of optical network units through one of the second optical splitters, the branch optical fibers which are connected with the branch ports of the first-level optical splitter are respectively connected with a wavelength reflector in series, the public port of the first-level optical splitter is connected with an optical absorber, and the different wavelength reflectors have different transmission wavelengths and different reflection wavelengths.

The invention provides a recovery method for protection service in an intelligent optical network and relates to the field of intelligent optical networks; and the invention also solves the problem that the switching time under the GMPLS (Generalized Multiprotocol Label Switching) protocol is longer and the service is affected. The recovery method comprises the steps of: monitoring a switching recovery protection group constituted by a working port and a protection port; selecting a new port and establishing a path with the new port when the port in the switching recovery protection group is in fault; and replacing the fault port with the new port and updating the new port to the switching recovery protection group. The technical scheme provided by the invention is applicable to a WSON (Wavelength Switched Optical Network) and realizes the rapid switching and recovery under the GMPLS protocol.

The invention provides a multi-wavelength passive optical network system. The multi-wavelength passive optical network system comprises an optical line terminal, an optical distribution network and a plurality of optical network units. According to the multi-wavelength passive optical network system, the optical network units are divided into a plurality of groups, each group of the optical network units adopts a specific uplink wavelength and a specific downlink wavelength, the optical distribution network comprises a first-level optical splitter and a plurality of second-level optical splitters, the first-level optical splitter comprises an uplink public port, a downlink public port, a plurality of uplink branch ports and a plurality of downlink branch ports, the downlink branch ports of the first-level optical splitter are connected with downlink branch optical fibers which are respectively connected with a wavelength reflector in series, the downlink public port of the first-level optical splitter is connected with an optical absorber, and the different wavelength reflectors have different transmission wavelengths and different reflection wavelengths.

The invention discloses a path calculation method and system, and relates to the technical field of communication. The path calculation method is applied to a wavelength switched optical network (WSON), and comprises the following steps: receiving a plurality of path calculation requests, grouping all the path calculation requests, and calculating K shortest paths from a source node of each group to a sink node of the group, wherein each group is provided with a source node and a destination node, and the wavelength channels of the K shortest paths in each group are used for meeting the path calculation request of the group; in all the K shortest paths, performing path segmentation by taking the relay node as a segmentation point, and storing the sub-paths conforming to the resource constraint into a sub-path set; constructing a linear programming model based on all the K shortest paths and the resource constraints, and determining an optimal path set meeting the most path calculation requests according to the linear programming model. According to the invention, under the condition that network resources are limited, more reachable paths are calculated so as to recover more services.

The invention discloses a collision avoidance wavelength assignment method based on a PCE (Personal Computer Equipment), relating to the technical field of wavelength switched optical networks. The method comprises the following steps of: C, sending Path information to a destination node by a source node; D, after receiving the Path information by the destination node, judging whether a light path available wavelength set is empty, if so, sending PathErr information to the source node by the destination node and executing a step C; if not, selecting one wavelength as a reserved wavelength, and executing a step E; E, sending RESVReq information to the PCE by the destination node; and F, judging whether the current reserved wavelength is available by the PCE, if so, storing Path ID of the Path information, the current reserved wavelength and RID in a CAT (Computer Aided Translation) table, and notifying the destination node to send Resv information; if not, selecting a new available wavelength as the reserved wavelength, and executing the step E. According to the method disclosed by the invention, the network backward resource collision probability can be reduced, therefore, the network blocking rate is reduced.

The present invention relates to a system and method for distributing digital signals over wavelength-switched optical transport networks with long-distance optical multicasting capability comprising a transmitter module and a receiver module in the headend of primary network and in the local node, respectively, for multicasting IPTV channels with HDTV, UHDTV and 3DTV signals. The transmitter module comprises an Ethernet switch, three DPSK modulators and a DWDM optical multiplexer. The receiver module comprises an Ethernet switch, three DPSK demodulators and a DWDM optical demultiplexer. In a novel manner, both modules combine 2 Gbps digital transmission, RZ-DPSK modulation and optical multicasting over a wavelength-switched optical network, WSON.

A method of allocating a wavelength to a lightpath in a wavelength multiplex for use in an optical network comprising nodes connected by optical links, wherein the wavelength multiplex is adapted to support lightpaths of two different bitrates. The disclosed method allows for efficient allocation of wavelengths that prevents wasting bandwidth and mitigates detrimental effects of cross-phase modulation.

The invention provides a multi-wavelength passive optical network system which comprises an optical line terminal, an optical distribution network and a plurality of optical network units. The plurality of optical network units are divided into multiple groups, and different uplink and downlink wavelengths are adopted for each group of optical network units. The optical distribution network comprises a first stage optical splitter and a plurality of second stage optical splitters. The first stage optical splitter comprises an uplink public port, a downlink public port, a plurality of uplink branch ports and a plurality of downlink branch ports. The uplink public port and the downlink public port are connected onto the optical line terminal through an uplink main optical fiber and a downlink main optical fiber respectively. The downlink branch ports and the uplink branch ports of the first stage optical splitter are connected onto downlink branch optical fibers and uplink branch optical fibers respectively and are connected onto one group of optical network units through one second stage optical splitter. Each wave dividing assembly comprises optical circulators with four ports and fiber bragg gratings, and the fiber bragg gratings of different wave dividing assemblies have different reflectance spectrums.

The invention discloses a method and a system for inheriting and selecting a 1+1 rerouting channel for restoring an optical layer in a WSON, and relates to the field of intelligent optical switching networks. The method comprises the following steps: in restoring the 1+1 protection mode, when both the active channel and the standby channel are interrupted, it is judged whether the active and standby channels have the wavelength conversion function; if the active and standby channels do not have the wavelength conversion function, the active line is used If the calculation fails, use the backup line disk and wavelength for routing calculation; if the active and standby channels have the wavelength conversion function, use the line disk and wavelength of the last faulty channel to perform rerouting recovery. If the rerouting recovery If it fails, perform wavelength conversion, use the same line panel, and change the wavelength for rerouting recovery. The invention can reasonably select the rerouting channel according to the actual situation.

The present invention provides an apparatus comprising a Path Computation Element (PCE) for at least local impairment aware Routing and Wavelength Allocation (RWA) and based on the ability to support Path Routing, Wavelength Allocation (WA) and The PCE Protocol (PCEP) detracts from the Verification (IV) and communicates with the Path Computation Client (PCC). The PCEP includes at least one operation selected from the group consisting of a new RWA path request operation and a path reoptimization request operation. The present invention also discloses a network component, the network component comprising at least one processor for executing a method, the method comprising: establishing a PCEP session with a PCC; receiving path calculation information from the PCC, the path calculation information including RWA information and constraints; and establishing an impairment-aware RWA (IA-RWA) based on the path computation information and the vendor's equipment's private impairment information.

The invention provides a multi-wavelength passive optical network system. The multi-wavelength passive optical network system comprises an optical line terminal, an optical distribution network and a plurality of optical network units. According to the multi-wavelength passive optical network system, the optical distribution network comprises a first-level optical splitter and a plurality of second-level optical splitters, the public port of the first-level optical splitter is connected to the optical line terminal through a main optical fiber, the branch ports of the first-level optical splitter are connected with branch optical fibers respectively and are connected to one group of optical network units through one of the second optical splitters, the branch optical fibers which are connected with the branch ports of the first-level optical splitter are respectively connected with a wavelength reflector in series, the public port of the first-level optical splitter is connected with an optical absorber, and the different wavelength reflectors have different transmission wavelengths and different reflection wavelengths; the optical line terminal sends a downlink XGTC frame to the optical network, and the frame header of the downlink XGTC frame comprises an HLend domain, and the HLend domain comprises a wavelength indicating filed which is used for carrying wavelength indicating information.

The present invention relates to a method and a node for distributing physical (PI) parameters used when establishing an optical path for user traffic through routing and wavelength assignment of optical channels carried in optical links in a wavelength-switched optical network (WSON) entity. It is also an object of the present invention to specify an object format to be introduced in a link-state routing protocol, such as the OSPF-TE protocol, configured to carry information about physical impairments. When considering dynamic wavelength provisioning, this information set is required for the feasibility evaluation of lightpaths to be established across the optical switched network controlled by the WSON control plane.