Method and device for routing computation in large-scale OTN network

Abstract

The application provides a large-scale OTN network routing calculation method and device, the method comprising: generating an optical channel label according to each first potential optical channel, and putting into a first queue; taking out an optical channel label with the minimum total cost from the first queue as a first label; if there is no other optical channel label with the same destination node and wavelength as the first label and taken out, constructing a target path; if the destination node of the first label is not the destination node of the service, and the target path is successfully constructed, generating an optical channel label according to each second potential optical channel, and putting into the first queue; if the destination node of the first label is not the destination node of the service, and the first queue is not empty, taking out a new first label; if the destination node of the first label is the destination node of the service, and the target path is successfully constructed, connecting the target path corresponding to the first label and all forward labels to obtain an optimal service path. Through the application, the routing calculation efficiency of the large-scale OTN network is significantly improved.

Description

Technical Field

[0001] This application relates to the field of OTN routing calculation technology, specifically to a method and apparatus for large-scale OTN network routing calculation. Background Technology

[0002] In the field of optical transmission networks, with the rapid development of communication technology, network scale continues to expand, and service demands are becoming increasingly complex and diverse. In the early stages of network construction, operators provide the network's node and link layout, as well as a service planning matrix. Design institutes and other entities then allocate network-wide path resources based on this matrix. The service planning matrix only specifies source and destination nodes and optical channel types, such as 100G, 200G, or 400G. Planning work requires determining the resources such as end-to-end paths, wavelengths, relays, and line ports. Facing ultra-large-scale networks (1000 nodes, 3000 links or more), rapid service planning has become a key trend in optical network planning. Simultaneously, as OTN networks continue to expand, fault recovery and capacity expansion of existing networks also urgently require efficient algorithm support.

[0003] In existing technologies, integer linear programming can solve the multi-objective optimization problem of optical transmission network service planning, but its efficiency is extremely low in large-scale network scenarios. Currently, a better approach for large-scale networks is to break it down into three sub-problems: calculating K paths using the K-Shortest Path Algorithm, sequentially assigning relays to these K paths, and then assigning channels to the paths with assigned relays. However, due to the limitations of Dijkstra's algorithm, its search space is a gradually expanding circle; a path can only be found when the radius of the circle includes both source and destination nodes. This means that in large-scale networks, K must be maximized to calculate all services, severely impacting computational efficiency and the timeliness of resource allocation. Therefore, a new, fast algorithm is urgently needed to meet the service planning requirements of large-scale optical transmission networks. Summary of the Invention

[0004] This application provides a method and apparatus for large-scale OTN network routing calculation, which can solve the technical problem of low efficiency in large-scale OTN network routing calculation in the prior art.

[0005] In a first aspect, embodiments of this application provide a method for calculating routes in a large-scale OTN network, the method comprising:

[0006] An optical channel label is generated for each first potential optical channel and placed in the first queue. The source node of the first potential optical channel is the source node of the service. The fields of the optical channel label include the previous label, source node, destination node, wavelength, total cost and OSNR threshold. The total cost is the sum of the actual cost of the constructed path and the estimated cost of the unconstructed path.

[0007] Take the optical channel label with the lowest total cost from the first queue as the first label;

[0008] If there are no destination nodes and other optical channel labels with wavelengths consistent with the first label that have been extracted, then construct a target path, wherein the target path satisfies the source node, destination node, wavelength and OSNR threshold requirements of the first label;

[0009] If the destination node of the first label is not the destination node of the business, and the target path is successfully constructed, then the first label is used as the previous label, and an optical channel label is generated according to each second potential optical channel and placed in the first queue. The source node of the second potential optical channel is the destination node of the first label, and the destination node of the second potential optical channel does not appear in the target path corresponding to the first label and all its forward labels.

[0010] If the destination node of the first label is not the destination node of the business, and the first queue is not empty, then a new first label is retrieved.

[0011] If the destination node of the first label is the destination node of the business, and the target path is successfully constructed, then the target paths corresponding to the first label and all its forward labels are connected to obtain the optimal business path.

[0012] Furthermore, in one embodiment, the step of constructing the target path includes:

[0013] An optical link label is constructed based on the first available link and placed in the second queue. The requirements for the available link include: the destination node does not appear in the target path corresponding to all the forward labels of the first label; the wavelength of the first label is not occupied; the source node of the first available link is the source node of the first label; and the fields of the optical link label include the previous label, the destination node, and the total cost.

[0014] Take the optical link label with the lowest total cost from the second queue as the second label;

[0015] If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node is the same as the second label and has been taken out, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue, wherein the source node of the second available link is the destination node of the second label.

[0016] If the destination node of the second label is not the destination node of the first label, and the second queue is not empty, then a new second label is retrieved.

[0017] If the destination node of the second label is the destination node of the first label, then the links corresponding to the second label and all its forward labels are connected to obtain the optimal optical path.

[0018] If the equivalent OSNR value of the optimal optical path is less than the OSNR threshold of the first tag, then the optimal optical path is determined as the target path.

[0019] Furthermore, in one embodiment, the requirement for an available link also includes: the absence of an optical link label that is consistent with the destination node and has been retrieved.

[0020] Furthermore, in one embodiment, the field of the optical link label also includes the equivalent OSNR value of the constructed path;

[0021] If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node matches the second label and have been retrieved, then the step of constructing an optical link label based on each second available link and placing it in the second queue includes:

[0022] If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been extracted, and the equivalent OSNR value of the constructed path of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

[0023] Furthermore, in one embodiment, the field of the optical link label also includes a total OSNR value, which is the sum of the equivalent OSNR value of the constructed path and the estimated OSNR value of the unconstructed path;

[0024] If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node matches the second label and have been retrieved, then the step of constructing an optical link label based on each second available link and placing it in the second queue includes:

[0025] If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been retrieved, and the total OSNR value of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

[0026] Furthermore, in one embodiment, there is no host node and no optical channel tag whose wavelength is consistent with the second potential optical channel and which has been removed.

[0027] Furthermore, in one embodiment, the cost types involved in the optical channel label include wavelength cost, local group cost, relay cost, and link length cost.

[0028] Further, in one embodiment, before the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, and actual relay cost of the label and all its forward labels, the actual link length cost of all forward labels, the estimated link length cost of the label, and the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

[0029] After the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, actual relay cost, and actual link length cost of the label and all its forward labels, as well as the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

[0030] Furthermore, in one embodiment, the step of generating an optical channel tag based on each first potential optical channel and placing it into the first queue further includes:

[0031] The minimum link length between any two nodes is calculated using Dijkstra's algorithm.

[0032] If the minimum link length between any two nodes is less than a preset length threshold, it is determined that there is a potential optical channel between the two nodes. The wavelength of the potential optical channel is the wavelength that the source node can emit and the destination node can receive.

[0033] Secondly, embodiments of this application also provide a large-scale OTN network routing calculation device, the large-scale OTN network routing calculation device comprising:

[0034] The initialization module is used to generate optical channel labels for each first potential optical channel and put them into the first queue. The source node of the first potential optical channel is the source node of the service. The fields of the optical channel label include the previous label, source node, destination node, wavelength, total cost and OSNR threshold. The total cost is the sum of the actual cost of the constructed path and the estimated cost of the unconstructed path.

[0035] The tag extraction module is used to extract the optical channel tag with the lowest total cost from the first queue as the first tag;

[0036] The path construction module is used to construct a target path if there is no destination node and other optical channel labels with wavelengths consistent with the first label that have been extracted. The target path satisfies the source node, destination node, wavelength and OSNR threshold requirements of the first label.

[0037] The tag extension module is used to take the first tag as the previous tag if the destination node of the first tag is not the destination node of the business and the target path is successfully constructed. Then, it generates an optical channel tag according to each second potential optical channel and puts it into the first queue. The source node of the second potential optical channel is the destination node of the first tag, and the destination node of the second potential optical channel does not appear in the target path corresponding to the first tag and all its forward tags.

[0038] The callback module is used to retrieve a new first tag if the destination node of the first tag is not the destination node of the business and the first queue is not empty.

[0039] The result output module is used to connect the target paths corresponding to the first label and all its forward labels to obtain the optimal path for the business if the destination node of the first label is the destination node of the business and the target path is successfully constructed.

[0040] In this application, the path search algorithm is executed in two layers. The first-layer search algorithm expands the path based on the potential optical channel as a whole. Through the management mechanism of optical channel labels and the first queue, the optical channel expands from the source node of the service to the destination node of the service. In the expanded path, different optical channels of the same wavelength will not intersect, and a single path will not form a loop. Only the optimal label taken from the first queue will trigger the second-layer search algorithm. The second layer specifies the node links traversed by the potential optical channel and determines whether the OSNR threshold requirement is met. This application avoids the drawback of Dijkstra's algorithm blindly expanding the search space, significantly reduces the time cost of searching paths, and significantly improves the algorithm efficiency, making it particularly suitable for ultra-large-scale network service planning. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating a large-scale OTN network routing calculation method in one embodiment of this application;

[0042] Figure 2 This is a schematic diagram of the physical topology in one embodiment of this application;

[0043] Figure 3 for Figure 2 A schematic diagram of the potential optical channels corresponding to the physical topology in the illustrated embodiment;

[0044] Figure 4 This is a schematic diagram of the functional modules of a large-scale OTN network routing calculation device in one embodiment of this application. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0046] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0047] Nodes: The nodes in this application are optical add-drop multiplexing nodes, which include local groups and relays.

[0048] Local group: An optical add-drop multiplexing device used to combine and split optical signals.

[0049] Relay: The starting point of the optical channel. Generally speaking, relays are relatively expensive and are the devices whose costs need to be controlled the most.

[0050] Link: The link in this application is an optical fiber link, which is a physical path connecting two nodes. Its model, length and equivalent OSNR (optical signal-to-noise ratio) value are known.

[0051] Optical path: A logical path used to transmit optical signals in an optical network, passing through a series of optical fiber links. Each optical path has the same wavelength, and the equivalent OSNR value of the optical fiber links it passes through is less than the equivalent OSNR threshold for light energy to pass through.

[0052] Business: A connection request from the source node to the destination node.

[0053] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0054] In a first aspect, embodiments of this application provide a method for calculating routing in a large-scale OTN network.

[0055] Figure 1 A flowchart illustrating a large-scale OTN network routing calculation method according to an embodiment of this application is shown.

[0056] Reference Figure 1 In one embodiment, the large-scale OTN network routing calculation method includes the following steps:

[0057] S1. Generate an optical channel label for each first potential optical channel and place it in the first queue. The source node of the first potential optical channel is the source node of the service. The fields of the optical channel label include the previous label, source node, destination node, wavelength, total cost and OSNR threshold. The total cost is the sum of the actual cost of the constructed path and the estimated cost of the unconstructed path.

[0058] Specifically, a potential optical channel is defined as follows: if the optical signal of a preset wavelength emitted by the first node is estimated to be received by the second node without the use of a relay, then a potential optical channel is considered to exist, with the source node, destination node, and wavelength being the first node, the second node, and the preset wavelength, respectively.

[0059] It should be noted that, in practice, the determination of whether a relay is needed is based on whether the equivalent OSNR value is less than the corresponding OSNR threshold. When judging potential optical channels, a simpler method can be used to estimate the optical propagation between two nodes to reduce the amount of computation.

[0060] The total cost of an optical channel label is the sum of the actual cost of the established paths between the source and destination nodes of the service for that label and all its preceding labels (the previous label, the label before the previous label, etc.) and the estimated cost of the unestablished paths. For the same path, the estimated cost is less than the actual cost and is as close to the actual cost as possible to ensure the correctness and speed of the algorithm.

[0061] Optionally, the calculation method and the types of costs considered can be set as needed. For example, in OTN network routing calculations, wavelength cost, local group cost, relay cost, and link length cost are usually considered.

[0062] Figure 2 A schematic diagram of the physical topology in one embodiment of this application is shown. Figure 3 It shows Figure 2 A schematic diagram of the potential optical channels corresponding to the physical topology in the illustrated embodiment.

[0063] Reference Figure 2 and Figure 3 Example A1: Node 1 is the source node of the service. Considering only one wavelength, the potential optical channels and optical channel labels are simplified to source node number - destination node number. Then the first potential optical channels are 1-2, 1-3 and 1-6, generating three optical channel labels.

[0064] S2. Take the optical channel label with the smallest total cost from the first queue as the first label.

[0065] Optionally, the first queue and the second queue mentioned later can be a Fibonacci heap, a max-heap, a min-heap, or a binomial heap.

[0066] Optionally, when there is more than one smallest optical channel label in the first queue, the optical channel label with the smallest wavelength number is selected as the first label.

[0067] S3. If there are no destination nodes and other optical channel labels with wavelengths consistent with the first label that have been extracted, then construct a target path, wherein the target path satisfies the source node, destination node, wavelength and OSNR threshold requirements of the first label.

[0068] Specifically, the premise for constructing the target path is that there are no destination nodes and other optical channel labels with the same wavelength as the first label that have been extracted, thereby ensuring that different optical channels of the same wavelength will not intersect in the expanded path.

[0069] When constructing the target path, the optimal path that meets the source node, destination node, and wavelength requirements of the first label is first constructed. Then, it is determined whether the path meets the OSNR threshold requirement of the first label. Only optical channel labels taken from the first queue will have actual node links constructed, thus significantly reducing the computational cost of constructing node links. The OSNR threshold is used to ensure that the prediction of potential optical channels is correct, thereby ensuring that the total cost of optical channel labels is accurate and reliable.

[0070] Since optical channel labels are established based on potential optical channels, the span between two nodes will not be too large, which is equivalent to a small-scale business request. The path construction method can refer to the solutions in related technologies. Optional implementation methods will also be provided later, so they will not be elaborated here.

[0071] Reference Figure 2 and Figure 3 Example A2: Continuing the settings of Example A1, the first optical channel labels retrieved are 1-6, and the target path constructed is "node 1-3-6".

[0072] S4. If the destination node of the first label is not the destination node of the business and the target path is successfully constructed, then the first label is used as the previous label, and an optical channel label is generated according to each second potential optical channel and placed in the first queue. The source node of the second potential optical channel is the destination node of the first label, and the destination node of the second potential optical channel does not appear in the target path corresponding to the first label and all its forward labels.

[0073] Specifically, if the destination node of the first tag is not the destination node of the business, it means that the business path has not yet been completed. If the target path is successfully constructed, it means that this path has value for further expansion. The path is expanded by adding an optical channel tag generated based on the second potential optical channel to the first queue. The expansion is completed when the newly added tag is retrieved and the target path is successfully constructed.

[0074] Specifically, the destination node of the second potential optical channel does not appear in the target path corresponding to the first label and all its forward labels, thus ensuring that a single path does not form a loop.

[0075] Reference Figure 2 and Figure 3 Example A3: Continuing the settings of Example A2, the potential optical channels with node 6 as the source node are 6-1, 6-2, 6-3, 6-4, and 6-7. Nodes 1 and 3 appear in the target path "node 1-3-6" corresponding to the optical channel label 1-6. Therefore, the second potential optical channels corresponding to the optical channel label 1-6 are 6-2, 6-4, and 6-7, generating three optical channel labels.

[0076] S5. If the destination node of the first label is not the destination node of the business, and the first queue is not empty, then retrieve a new first label.

[0077] Correspondingly, if the destination node of the first label is not the destination node of the business, and the first queue is empty, then the optimal path construction for the business is deemed to have failed.

[0078] S6. If the destination node of the first label is the destination node of the business, and the target path is successfully constructed, then connect the target paths corresponding to the first label and all its forward labels to obtain the optimal path of the business.

[0079] Optionally, after calculating the optimal business path, the total cost of the optimal business path can be further verified to determine whether to use the path in the end.

[0080] Therefore, in this embodiment, the path search algorithm is executed in two layers. The first-layer search algorithm expands the path based on the potential optical channel as a whole. Through the management mechanism of optical channel labels and the first queue, the optical channel expands from the source node of the service to the destination node of the service. In the expanded path, different optical channels of the same wavelength will not intersect, and a single path will not form a loop. Only the optimal label taken from the first queue will trigger the second-layer search algorithm. The second layer specifies the node links traversed by the potential optical channel and determines whether the OSNR threshold requirement is met. This embodiment avoids the drawback of Dijkstra's algorithm blindly expanding the search space, significantly reduces the time cost of searching paths, and significantly improves the algorithm efficiency, making it particularly suitable for ultra-large-scale network service planning.

[0081] Furthermore, in one embodiment, there is no host node and no optical channel tag whose wavelength is consistent with the second potential optical channel and which has been removed.

[0082] In this embodiment, considering that if there is a destination node and a wavelength that is consistent with a certain potential optical channel and the optical channel label has been taken out, then after the optical channel label generated according to the potential optical channel is put into the first queue and taken out, the path construction and path expansion operations cannot be performed, resulting in unnecessary computation and time consumption. Therefore, a constraint condition for the second potential optical channel is added to further reduce the computation and improve the routing calculation efficiency.

[0083] Figure 4 It shows Figure 3 A schematic diagram illustrating the generation of optical channel tags in the illustrated embodiment.

[0084] Reference Figure 3 and Figure 4 Example A4: Continuing the setup of Example A3, the second extracted optical channel label is 1-2, and the target path constructed is node 1-2. The potential optical channels with node 2 as the source node are 2-1, 2-4, 2-5, and 2-6. Node 1 appears in the target path "node 1-2" corresponding to optical channel label 1-2. Node 6 is the destination node of the extracted optical channel label 1-6. Therefore, the second potential optical channels corresponding to optical channel label 1-2 are 2-4 and 2-5, generating two optical channel labels.

[0085] Furthermore, in one embodiment, the cost types involved in the optical channel label include wavelength cost, local group cost, relay cost, and link length cost.

[0086] In this embodiment, by comprehensively considering wavelength cost, local group cost, relay cost and link length cost, and by adjusting the weights of various types of costs when superimposed, the optimal solution to the multi-objective optimization problem can be obtained.

[0087] For example, the cost of adding a new relay at each node is set to 1e8, the cost of the local group on the node is set to 1e8, the coefficient of the link wavelength is 1000, the first wave is 0, and each subsequent wave is the cube of the wavelength number. For example, the cost of using channel number 10 is 1000*10*10*10=1e6.

[0088] Specifically, before the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, and actual relay cost of the label and all its forward labels, the actual link length cost of all forward labels, the estimated link length cost of the label, and the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

[0089] After the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, actual relay cost, and actual link length cost of the label and all its forward labels, as well as the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

[0090] Furthermore, in one embodiment, the field of the optical channel label also includes the actual forward cost. Before the target path corresponding to an optical channel label is constructed, the actual forward cost of the label is the sum of the actual forward cost of the previous label and the actual wavelength cost, actual local group cost, and actual relay cost of the label. The total cost of the label is the sum of the actual forward cost of the label, the estimated link length cost of the label, and the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

[0091] After the target path corresponding to an optical channel label is constructed, the actual forward cost of the label is the sum of the actual forward cost of the previous label and the actual wavelength cost, actual local group cost, actual relay cost, and actual link length cost of the label. The total cost of the label is the sum of the actual forward cost of the label and the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the label's destination node to the service's destination node.

[0092] In this embodiment, by adding a field for actual forward cost to the optical channel label, the actual forward cost of each optical channel label can be calculated by the actual forward cost of the previous label and the newly added actual cost of the label. It is not necessary to find all forward labels for calculation, which facilitates the rapid calculation of the actual forward cost. Then, the estimated cost is added on the actual forward cost to quickly calculate the total cost.

[0093] Furthermore, in one embodiment, the step of generating an optical channel tag based on each first potential optical channel and placing it into the first queue further includes:

[0094] The minimum link length between any two nodes is calculated using Dijkstra's algorithm.

[0095] If the minimum link length between any two nodes is less than a preset length threshold, it is determined that there is a potential optical channel between the two nodes. The wavelength of the potential optical channel is the wavelength that the source node can emit and the destination node can receive.

[0096] In this embodiment, when determining potential optical channels, a threshold judgment is made based on the link length. The link length is positively correlated with the equivalent OSNR value, which facilitates the rapid identification of potential optical channels and ensures a certain degree of accuracy.

[0097] For example, if the minimum link length between node A and node B is less than a preset length threshold, and both node A and node B can transmit and receive wavelengths 1, 2, and 3, then there are three potential optical channels with node A as the source node, node B as the destination node, and wavelengths 1, 2, and 3 respectively, and three potential optical channels with node B as the source node, node A as the destination node, and wavelengths 1, 2, and 3 respectively, for a total of six potential optical channels.

[0098] Furthermore, in one embodiment, the step of constructing the target path includes:

[0099] An optical link label is constructed based on the first available link and placed in the second queue. The requirements for the available link include: the destination node does not appear in the target path corresponding to all the forward labels of the first label; the wavelength of the first label is not occupied; the source node of the first available link is the source node of the first label; and the fields of the optical link label include the previous label, the destination node, and the total cost.

[0100] Take the optical link label with the lowest total cost from the second queue as the second label;

[0101] If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node is the same as the second label and has been taken out, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue, wherein the source node of the second available link is the destination node of the second label.

[0102] If the destination node of the second label is not the destination node of the first label, and the second queue is not empty, then a new second label is retrieved.

[0103] If the destination node of the second label is the destination node of the first label, then the links corresponding to the second label and all its forward labels are connected to obtain the optimal optical path.

[0104] If the equivalent OSNR value of the optimal optical path is less than the OSNR threshold of the first tag, then the optimal optical path is determined as the target path.

[0105] In this embodiment, the management mechanism of the optical link label and the second queue is similar to that of the optical channel label and the first queue, so that the optical link extends from the source node of the first label to the destination node of the first label. In the extended path, different paths will not intersect, and a single path will not form a loop.

[0106] Furthermore, in one embodiment, the requirement for an available link also includes: the absence of an optical link label that is consistent with the destination node and has been retrieved.

[0107] In this embodiment, considering that if there is a destination node that is consistent with a certain link and the optical link label has been retrieved, the optical link label generated based on that link will be placed in the second queue and retrieved, but the path extension operation cannot be performed, resulting in unnecessary computation and time consumption, a new restriction condition for available links is added to further reduce the computation and improve the routing calculation efficiency.

[0108] Furthermore, in one embodiment, the field of the optical link label also includes the equivalent OSNR value of the constructed path;

[0109] If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node matches the second label and have been retrieved, then the step of constructing an optical link label based on each second available link and placing it in the second queue includes:

[0110] If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been extracted, and the equivalent OSNR value of the constructed path of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

[0111] In this embodiment, when determining whether to expand the second label, the equivalent OSNR value of the already constructed path is additionally considered. If the equivalent OSNR value of the already constructed path is greater than or equal to the OSNR threshold of the first label, then this path has no value for further expansion, and the final constructed output path will inevitably fail to meet the threshold requirement. This embodiment allows for the early termination of some path expansions, reducing unnecessary computation and improving the algorithm's correctness.

[0112] Furthermore, in one embodiment, the field of the optical link label also includes a total OSNR value, which is the sum of the equivalent OSNR value of the constructed path and the estimated OSNR value of the unconstructed path;

[0113] If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node matches the second label and have been retrieved, then the step of constructing an optical link label based on each second available link and placing it in the second queue includes:

[0114] If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been retrieved, and the total OSNR value of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

[0115] In this embodiment, when determining whether to expand the second label, the total OSNR value is additionally considered. The total OSNR value is the sum of the equivalent OSNR value of the constructed path and the estimated OSNR value of the unconstructed path. If the total OSNR value is greater than or equal to the OSNR threshold of the first label, the value of continuing to expand this path is very low, and the final constructed path is likely not to meet the threshold requirement. This embodiment can terminate the expansion of some paths in advance, reduce unnecessary computation, and improve the correctness of the algorithm.

[0116] Optionally, the calculation of the equivalent OSNR value of the constructed path can refer to the calculation of the actual forward cost in the optical channel label, and improve the calculation efficiency by iteratively calculating through the previous label.

[0117] For example, the cost types involved in optical channel labels include link length costs.

[0118] Optionally, the field of the optical link label can also include the actual forward cost. The actual forward cost can be quickly calculated by iterative calculation of the previous label, and then the estimated cost can be added on the actual forward cost to quickly calculate the total cost.

[0119] Secondly, embodiments of this application also provide a large-scale OTN network routing calculation device.

[0120] Figure 4 A schematic diagram of the functional modules of a large-scale OTN network routing calculation device in one embodiment of this application is shown.

[0121] Reference Figure 4 In one embodiment, the large-scale OTN network routing calculation device includes:

[0122] The initialization module 10 is used to generate an optical channel label for each first potential optical channel and put it into the first queue. The source node of the first potential optical channel is the source node of the service. The fields of the optical channel label include the previous label, source node, destination node, wavelength, total cost and OSNR threshold. The total cost is the sum of the actual cost of the constructed path and the estimated cost of the unconstructed path.

[0123] The tag extraction module 20 is used to extract the optical channel tag with the smallest total cost from the first queue as the first tag;

[0124] The path construction module 30 is used to construct a target path if there is no destination node and other optical channel labels with wavelengths consistent with the first label that have been extracted. The target path satisfies the source node, destination node, wavelength and OSNR threshold requirements of the first label.

[0125] The tag extension module 40 is used to take the first tag as the previous tag if the destination node of the first tag is not the destination node of the business and the target path is successfully constructed. Then, it generates an optical channel tag according to each second potential optical channel and puts it into the first queue. The source node of the second potential optical channel is the destination node of the first tag, and the destination node of the second potential optical channel does not appear in the target path corresponding to the first tag and all its forward tags.

[0126] Callback module 50 is used to retrieve a new first tag if the destination node of the first tag is not the destination node of the business and the first queue is not empty.

[0127] The result output module 60 is used to connect the target paths corresponding to the first label and all its forward labels to obtain the optimal path for the business if the destination node of the first label is the destination node of the business and the target path is successfully constructed.

[0128] Furthermore, in one embodiment, the path construction module 30 is used for:

[0129] An optical link label is constructed based on the first available link and placed in the second queue. The requirements for the available link include: the destination node does not appear in the target path corresponding to all the forward labels of the first label; the wavelength of the first label is not occupied; the source node of the first available link is the source node of the first label; and the fields of the optical link label include the previous label, the destination node, and the total cost.

[0130] Take the optical link label with the lowest total cost from the second queue as the second label;

[0131] If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node is the same as the second label and has been taken out, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue, wherein the source node of the second available link is the destination node of the second label.

[0132] If the destination node of the second label is not the destination node of the first label, and the second queue is not empty, then a new second label is retrieved.

[0133] If the destination node of the second label is the destination node of the first label, then the links corresponding to the second label and all its forward labels are connected to obtain the optimal optical path.

[0134] If the equivalent OSNR value of the optimal optical path is less than the OSNR threshold of the first tag, then the optimal optical path is determined as the target path.

[0135] Furthermore, in one embodiment, the requirement for an available link also includes: the absence of an optical link label that is consistent with the destination node and has been retrieved.

[0136] Furthermore, in one embodiment, the field of the optical link label also includes the equivalent OSNR value of the constructed path;

[0137] Path building module 30 is used for:

[0138] If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been extracted, and the equivalent OSNR value of the constructed path of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

[0139] Furthermore, in one embodiment, the field of the optical link label also includes a total OSNR value, which is the sum of the equivalent OSNR value of the constructed path and the estimated OSNR value of the unconstructed path.

[0140] Path building module 30 is used for:

[0141] If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been retrieved, and the total OSNR value of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

[0142] Furthermore, in one embodiment, there is no host node and no optical channel tag whose wavelength is consistent with the second potential optical channel and which has been removed.

[0143] Furthermore, in one embodiment, the cost types involved in the optical channel label include wavelength cost, local group cost, relay cost, and link length cost.

[0144] Further, in one embodiment, before the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, and actual relay cost of the label and all its forward labels, the actual link length cost of all forward labels, the estimated link length cost of the label, and the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

[0145] After the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, actual relay cost, and actual link length cost of the label and all its forward labels, as well as the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

[0146] Furthermore, in one embodiment, the large-scale OTN network routing calculation device further includes a channel identification module, used for:

[0147] The minimum link length between any two nodes is calculated using Dijkstra's algorithm.

[0148] If the minimum link length between any two nodes is less than a preset length threshold, it is determined that there is a potential optical channel between the two nodes. The wavelength of the potential optical channel is the wavelength that the source node can emit and the destination node can receive.

[0149] The functions of each module in the above-mentioned large-scale OTN network routing calculation device correspond to the steps in the above-mentioned large-scale OTN network routing calculation method embodiment, and their functions and implementation processes will not be described in detail here.

[0150] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0151] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0152] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0153] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0154] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0155] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0156] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for routing computation in a large OTN network, characterized in that, The large-scale OTN network routing calculation method includes: An optical channel label is generated for each first potential optical channel and placed in the first queue. The source node of the first potential optical channel is the source node of the service. The fields of the optical channel label include the previous label, source node, destination node, wavelength, total cost and OSNR threshold. The total cost is the sum of the actual cost of the constructed path and the estimated cost of the unconstructed path. Take the optical channel label with the lowest total cost from the first queue as the first label; If there are no destination nodes and other optical channel labels with wavelengths consistent with the first label that have been extracted, then construct a target path, wherein the target path satisfies the source node, destination node, wavelength and OSNR threshold requirements of the first label; If the destination node of the first label is not the destination node of the business, and the target path is successfully constructed, then the first label is used as the previous label, and an optical channel label is generated according to each second potential optical channel and placed in the first queue. The source node of the second potential optical channel is the destination node of the first label, and the destination node of the second potential optical channel does not appear in the target path corresponding to the first label and all its forward labels. If the destination node of the first label is not the destination node of the business, and the first queue is not empty, then a new first label is retrieved. If the destination node of the first label is the destination node of the business, and the target path is successfully constructed, then the target paths corresponding to the first label and all its forward labels are connected to obtain the optimal business path.

2. The large-scale OTN network routing calculation method as described in claim 1, characterized in that, The steps for constructing the target path include: An optical link label is constructed based on the first available link and placed in the second queue. The requirements for the available link include: the destination node does not appear in the target path corresponding to all the forward labels of the first label; the wavelength of the first label is not occupied; the source node of the first available link is the source node of the first label; and the fields of the optical link label include the previous label, the destination node, and the total cost. Take the optical link label with the lowest total cost from the second queue as the second label; If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node is the same as the second label and has been taken out, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue, wherein the source node of the second available link is the destination node of the second label. If the destination node of the second label is not the destination node of the first label, and the second queue is not empty, then a new second label is retrieved. If the destination node of the second label is the destination node of the first label, then the links corresponding to the second label and all its forward labels are connected to obtain the optimal optical path. If the equivalent OSNR value of the optimal optical path is less than the OSNR threshold of the first tag, then the optimal optical path is determined as the target path.

3. The large-scale OTN network routing calculation method as described in claim 2, characterized in that, The requirements for an available link also include: there is no optical link label that is consistent with the destination node and has already been retrieved.

4. The large-scale OTN network routing calculation method as described in claim 2, characterized in that, The optical link label also includes the equivalent OSNR value of the constructed path; If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node matches the second label and have been retrieved, then the step of constructing an optical link label based on each second available link and placing it in the second queue includes: If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been extracted, and the equivalent OSNR value of the constructed path of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

5. The large-scale OTN network routing calculation method as described in claim 2, characterized in that, The optical link label also includes a field for the total OSNR value, which is the sum of the equivalent OSNR value of the constructed path and the estimated OSNR value of the unconstructed path. If the destination node of the second label is not the destination node of the first label, and there are no other optical link labels whose destination node matches the second label and have been retrieved, then the step of constructing an optical link label based on each second available link and placing it in the second queue includes: If the destination node of the second label is not the destination node of the first label, there are no other optical link labels whose destination node is the same as the second label and have been retrieved, and the total OSNR value of the second label is less than the OSNR threshold of the first label, then the second label is used as the previous label, and an optical link label is constructed according to each second available link and placed in the second queue.

6. The large-scale OTN network routing calculation method as described in any one of claims 1 to 5, characterized in that, There is no host node and no optical channel tag whose wavelength matches that of the second potential optical channel and which has already been removed.

7. The large-scale OTN network routing calculation method as described in any one of claims 1 to 5, characterized in that, The cost types involved in optical channel labeling include wavelength cost, local group cost, relay cost, and link length cost.

8. The large-scale OTN network routing calculation method as described in claim 7, characterized in that, Before the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, and actual relay cost of the label and all its forward labels, the actual link length cost of all forward labels, the estimated link length cost of the label, and the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service. After the target path corresponding to an optical channel label is constructed, the total cost of the label includes: the actual wavelength cost, actual local group cost, actual relay cost, and actual link length cost of the label and all its forward labels, as well as the estimated wavelength cost, estimated local group cost, estimated relay cost, and estimated link length cost from the destination node of the label to the destination node of the service.

9. The large-scale OTN network routing calculation method as described in any one of claims 1 to 5, characterized in that, The method further includes the following steps before generating optical channel tags for each first potential optical channel and placing them into the first queue: The minimum link length between any two nodes is calculated using Dijkstra's algorithm. If the minimum link length between any two nodes is less than a preset length threshold, it is determined that there is a potential optical channel between the two nodes. The wavelength of the potential optical channel is the wavelength that the source node can emit and the destination node can receive.

10. A large-scale OTN network routing calculation device, characterized in that, The large-scale OTN network routing calculation device includes: The initialization module is used to generate optical channel labels for each first potential optical channel and put them into the first queue. The source node of the first potential optical channel is the source node of the service. The fields of the optical channel label include the previous label, source node, destination node, wavelength, total cost and OSNR threshold. The total cost is the sum of the actual cost of the constructed path and the estimated cost of the unconstructed path. The tag extraction module is used to extract the optical channel tag with the lowest total cost from the first queue as the first tag; The path construction module is used to construct a target path if there is no destination node and other optical channel labels with wavelengths consistent with the first label that have been extracted. The target path satisfies the source node, destination node, wavelength and OSNR threshold requirements of the first label. The tag extension module is used to take the first tag as the previous tag if the destination node of the first tag is not the destination node of the business and the target path is successfully constructed. Then, it generates an optical channel tag according to each second potential optical channel and puts it into the first queue. The source node of the second potential optical channel is the destination node of the first tag, and the destination node of the second potential optical channel does not appear in the target path corresponding to the first tag and all its forward tags. The callback module is used to retrieve a new first tag if the destination node of the first tag is not the destination node of the business and the first queue is not empty. The result output module is used to connect the target paths corresponding to the first label and all its forward labels to obtain the optimal path for the business if the destination node of the first label is the destination node of the business and the target path is successfully constructed.

Images