Routing method and device of multi-layer multi-domain optical transport network

Abstract

The invention discloses a routing method and device for a multi-layer multi-domain optical transport network. The method comprises the following steps: receiving a service request initiated by a starting Ethernet NEP in a source control domain network; determining a plurality of intermediate NEPs between the source control domain network and a destination control domain network within the service request; constructing a topological matrix at least according to the plurality of middle NEPs, and determining a target transmission link which meets a preset constraint condition and enables the link cost to be the lowest according to the topological matrix; and routing the service request from the starting Ethernet NEP to a terminating Ethernet NEP in the destination control domain network according to the target transmission link. According to the routing method and the routing device, the technical problems of relatively poor accuracy and relatively low efficiency of the determined routing link when the cross-domain service is routed by adopting a fixed routing strategy or a random routing strategy are solved.

Description

Technical Field

[0001] The present application relates to the field of network communication technology, and in particular to a routing method and device for a multi-layer and multi-domain optical transmission network. Background Art

[0002] With the increase in business volume and geographical expansion, cross-domain services have become a regular business demand. When establishing multi-domain end-to-end services, since the division of "domains" is generally based on different operators, different geographical locations of the same operator's network, or different switching technologies, the transmission networks of multiple domains often use multi-vendor equipment, and each domain adopts a privacy protection strategy and is relatively closed. In order to ensure the accessibility of end-to-end services, it is often necessary to consider the issue of multi-domain routing.

[0003] Traditional processing methods often fix the inter-domain routing forwarding strategy between two domains or randomly select inter-domain routing. However, due to limited inter-domain resources, this processing method easily leads to an increase in link blocking rate. Therefore, there is an urgent need for a routing strategy technology that can quickly provide end-to-end transmission links and ensure the success rate of efficient service establishment in a multi-layer and multi-domain environment.

[0004] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0005] The embodiments of the present application provide a routing method and device for a multi-layer and multi-domain optical transport network, so as to at least solve the technical problem that when a fixed routing strategy or a random routing strategy is used to route cross-domain services, the determined routing links have poor accuracy and low efficiency.

[0006] According to one aspect of an embodiment of the present application, a routing method for a multi-layer and multi-domain optical transport network is provided, comprising: receiving a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; determining a plurality of intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the plurality of intermediate NEPs include: a non-starting Ethernet NEP and a first ODU_NEP in the source control domain network, a second ODU_NEP in the intermediate control domain network between the source control domain network and the destination control domain, a non-terminating Ethernet NEP and a third ODU_NEP in the destination control domain network; constructing a topology matrix based on at least the plurality of intermediate NEPs, and determining a target transmission link that satisfies preset constraints and minimizes link cost based on the topology matrix; and routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link.

[0007] Optionally, a topology matrix is ​​constructed at least based on multiple intermediate NEPs, and a target transmission link that meets preset constraints and has the lowest link cost is determined based on the topology matrix, including: taking the starting Ethernet NEP, multiple intermediate NEPs and the terminating Ethernet NEP as rows and columns, and taking the link costs of sub-links between the NEPs corresponding to each row and each column as matrix elements to construct a first topology matrix; using the Dijkstra algorithm to analyze the first topology matrix to obtain a first transmission link that meets the constraints and has the lowest link cost, and taking the first transmission link as the target transmission link.

[0008] Optionally, a topology matrix is ​​constructed based on at least a plurality of intermediate NEPs, and a target transmission link that satisfies preset constraints and minimizes the link cost is determined based on the topology matrix, including: a non-starting Ethernet NEP or a first ODU_NEP in the source control domain network is used as the starting NEP in the source control domain network, and a non-terminating Ethernet NEP or a third ODU_NEP in the destination control domain network is used as the terminating NEP in the source control domain network, wherein the link cost of a sub-link between the starting NEP and the starting Ethernet NEP and the link cost of a sub-link between the terminating NEP and the terminating Ethernet NEP are both less than a preset threshold value. ; With the starting NEP, the terminating NEP, and the middle NEP between the starting NEP and the terminating NEP as rows and columns, and with the link costs of the sub-links between the NEPs corresponding to each row and each column as matrix elements, a second topology matrix is ​​constructed; the second topology matrix is ​​analyzed using the Dijkstra algorithm to obtain a second transmission link that satisfies the constraint conditions and minimizes the link cost; the third transmission link between the starting Ethernet NEP and the starting NEP and the fourth transmission link between the terminating NEP and the terminating Ethernet NEP are determined, and the target transmission link is composed of the third transmission link, the second transmission link, and the fourth transmission link.

[0009] Optionally, the link cost is a weighted average sum of the values ​​of the sub-links in preset link evaluation dimensions, and the link evaluation dimensions include at least one of the following: link distance, link resource utilization, number of hops, and link status.

[0010] Optionally, the constraint conditions include at least one of the following: the sum of the link distances of each sub-link is less than a preset first threshold, the sum of the link resource utilization rates of each sub-link is less than a preset second threshold, the sum of the hop counts of each sub-link is less than a preset third threshold, and the link status of each sub-link is normal.

[0011] Optionally, routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link includes: determining the control domain network to which each NEP on the target transmission link belongs, and obtaining the transmission sub-links in each control domain network, wherein the types of the control domain networks include: source control domain network, destination control domain network, and intermediate control domain network; adjusting the service request according to the type of the control domain network, and routing the adjusted service request to the terminating Ethernet NEP in the destination control domain network according to the transmission sub-links in each control domain network.

[0012] Optionally, adjusting the service request to be routed according to the type of the control domain network, including: for a transmission sub-link in the source control domain network, in the process of routing the service request from the starting Ethernet NEP to the non-starting Ethernet NEP, adding the second node information of the starting Ethernet NEP and the third node information of the non-starting Ethernet NEP in the service request; in the process of routing the service request from the current first ODU_NEP in the source control domain network to the next first ODU_NEP, adding the third node information of the non-starting Ethernet NEP, the fourth node information of the current first ODU_NEP and the fifth node information of the next first ODU_NEP in the service request; for a transmission sub-link in the intermediate control domain network, in the process of routing the service request from the current first ODU_NEP in the intermediate control domain network to the next first ODU_NEP, adding the third node information of the non-starting Ethernet NEP, the fourth node information of the current first ODU_NEP and the fifth node information of the next first ODU_NEP in the service request; In the process of routing the current second ODU_NEP to the next second ODU_NEP, the sixth node information of the current second ODU_NEP and the seventh node information of the next second ODU_NEP are added in the service request; for the transmission sub-link within the destination control domain network, in the process of routing the service request from the current third ODU_NEP within the destination control domain network to the next third ODU_NEP, the eighth node information of the current third ODU_NEP and the ninth node information of the next third ODU_NEP are added in the service request; in the process of routing the service request from the non-terminating Ethernet NEP to the terminating Ethernet NEP, the first node information of the terminating Ethernet NEP and the tenth node information of the non-terminating Ethernet NEP are added in the service request.

[0013] According to another aspect of an embodiment of the present application, a routing device for a multi-layer and multi-domain optical transport network is also provided, including: a receiving module, used to receive a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; a first determining module, used to determine a plurality of intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the intermediate NEPs include at least one of the following: a non-starting Ethernet NEP and a first ODU NEP in the source control domain network, a second ODU NEP in the intermediate control domain network between the source control domain network and the destination control domain, a non-terminating Ethernet NEP and a third ODU NEP in the destination control domain network; a second determining module, used to construct a topology matrix based on the starting Ethernet NEP, the plurality of intermediate NEPs, and the terminating Ethernet NEP, and determine a target transmission link that satisfies preset constraints and has the lowest link cost based on the topology matrix; a routing module, used to route the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link.

[0014] According to another aspect of an embodiment of the present application, a computer program product is further provided. The computer program product includes a stored computer program, wherein when the computer program is executed by a processor, the routing method of the multi-layer and multi-domain optical transport network is implemented.

[0015] According to another aspect of an embodiment of the present application, an electronic device is also provided, which includes: a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to execute the above-mentioned routing method of the multi-layer and multi-domain optical transmission network through the computer program.

[0016] In an embodiment of the present application, the collaborative controller first receives a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least the first node information of a terminating Ethernet NEP in a destination control domain network; then, a plurality of intermediate NEPs between the source control domain network and the destination control domain network in the service request are determined, wherein the plurality of intermediate NEPs include: a non-starting Ethernet NEP and a first ODU_NEP in the source control domain network, a second ODU_NEP in an intermediate control domain network between the source control domain network and the destination control domain, a non-terminating Ethernet NEP and a third ODU_NEP in the destination control domain network; then, a topology matrix is ​​constructed at least based on the plurality of intermediate NEPs, and a target transmission link that satisfies preset constraints and minimizes the link cost is determined based on the topology matrix, thereby effectively avoiding excessive concentration of resources on some links, achieving balanced allocation of network resources, and maximizing the overall throughput of the network and the success rate of service establishment; finally, the service request is routed from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link, thereby ensuring that the service request can cross multiple layers of networks and multiple control domains to achieve end-to-end service transmission. This solves the technical problem that when a fixed routing strategy or a random routing strategy is used to route cross-domain services, the accuracy and efficiency of the determined routing links are poor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 It is a hardware structure block diagram of a computer terminal (or mobile device) for implementing a routing method of a multi-layer and multi-domain optical transport network according to an optional embodiment of the present application;

[0019] Figure 2 is a flow chart of an optional routing method for a multi-layer and multi-domain optical transport network according to an embodiment of the present application;

[0020] Figure 3 It is a schematic diagram of an optional packet OTN network architecture of the related technology;

[0021] Figure 4 is a topological diagram of an optional multi-domain optical transmission network according to an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of an optional multi-layer multi-domain optical transport network model according to an embodiment of the present application;

[0023] Figure 6is a schematic diagram of the principle of an optional global optimal algorithm according to an embodiment of the present application;

[0024] Figure 7 is a topological diagram of another optional multi-layer multi-domain optical transmission network according to an embodiment of the present application;

[0025] Figure 8 is a schematic diagram of the principle of an optional local optimal algorithm according to an embodiment of the present application;

[0026] Fig. 9 is a schematic diagram of an optional multi-layer multi-domain optical transport network according to an embodiment of the present application;

[0027] Fig.10 It is a schematic diagram of the structure of an optional routing device for a multi-layer and multi-domain network according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] In addition, the relevant information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for display, data for analysis, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. For example, an interface is set up between this system and the relevant user or organization. Before obtaining relevant information, it is necessary to send an acquisition request to the aforementioned user or organization through the interface, and obtain relevant information after receiving the consent information fed back by the aforementioned user or organization.

[0031] In order to better understand the embodiments of the present application, the technical terms involved in the embodiments of the present application are explained as follows:

[0032] OTN (Optical Transport Network): is a transmission network based on optical fiber technology, used to achieve the transmission and exchange of optical signals. It uses optical transmission to convert digital signals into optical signals for transmission to achieve high-speed, high-capacity and flexible data transmission. In other words, ONT transmits optical signals from one point to another by using optical transmission equipment and optical transmission protocols to achieve long-distance data communication.

[0033] NE (Network Element) is composed of one or more disks or frames, and can independently complete certain transmission functions. In simple terms, the 5G network is composed of multiple network elements, each of which has its own functions. The network elements in the 5G network include: access and mobility management function AMF network element, session management function SMF network element, user plane function UPF network element, unified data management function UDM network element, policy control function PCF network element, authentication server function AUSF network element, network slice selection NSSF network element.

[0034] Ethernet is a computer local area network technology that specifies the contents including physical layer connections, electronic signals and media access layer protocols.

[0035] ODUk (Optical channel Data Unit) provides signal-independent connectivity and plays a role in connection protection and monitoring. Therefore, its layer is also called the data channel layer. In ODUk, ODU can be translated as optical data unit (professionally called optical channel data unit), and k is the level of ODU, which can be 1, 2, and 3.

[0036] Example 1

[0037] According to an embodiment of the present application, an embodiment of a routing method for a multi-layer and multi-domain network is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Figure 1 The hardware structure block diagram of a computer terminal (or mobile device) for implementing a routing method of a multi-layer multi-domain optical transmission network is shown. Figure 1 As shown, the computer terminal 10 (or mobile device 10) may include one or more (102a, 102b, ..., 102n are used to illustrate) processors 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA), a memory 104 for storing data, and a transmission device 106 for communication functions. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the BUS bus), a network interface, a power supply and / or a camera. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above electronic device. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0039] It should be noted that the one or more processors 102 and / or other data processing circuits described above may generally be referred to herein as "data processing circuits". The data processing circuits may be embodied in whole or in part as software, hardware, firmware, or any other combination thereof. In addition, the data processing circuit may be a single independent processing module, or may be incorporated in whole or in part into any of the other components in the computer terminal 10 (or mobile device). As described in the embodiments of the present application, the data processing circuit acts as a processor control (e.g., selection of a variable resistor terminal path connected to an interface).

[0040] The memory 104 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the routing method of the multi-layer multi-domain optical transmission network in the embodiment of the present application. The processor 102 executes various functional applications and data processing by running the software programs and modules stored in the memory 104, that is, the routing method of the multi-layer multi-domain optical transmission network of the above-mentioned application program is realized. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the computer terminal 10 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0041] The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the computer terminal 10. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0042] The display may be, for example, a touch screen liquid crystal display (LCD) that enables a user to interact with a user interface of the computer terminal 10 (or mobile device).

[0043] In the above operating environment, Figure 2 is a flow chart of an optional routing method for a multi-layer multi-domain optical transport network according to an embodiment of the present application, such as Figure 2 As shown, the method at least includes steps S202-S208, wherein:

[0044] Step S202: receiving a service request initiated by a starting Ethernet point NEP in the source control domain network.

[0045] In the technical solution provided in step S202, when the collaborative controller routes the multi-layer and multi-domain optical transport network (OTN), it can first receive a service request initiated by the starting Ethernet NEP (i.e., the starting point of the service flow) in the source control domain network, wherein the starting Ethernet NEP (Network Element Point) can be a physical or virtual interface on a network device in the Ethernet network in the source control domain network that can initiate, receive or process data, such as a switch port, an Ethernet interface of a router, a network adapter of a server, or an Ethernet port on other network devices that can initiate or receive data transmission. The service request carries at least the first node information of the terminating Ethernet NEP (i.e., the end point of the service flow) in the destination control domain network, wherein the terminating Ethernet NEP (Network Element Point) can also be a physical or virtual interface on a network device in the Ethernet network in the destination control domain network that can initiate, receive or process data, such as a switch port, an Ethernet interface of a router, a network adapter of a server, or an Ethernet port on other network devices that can initiate or receive data transmission. The first node information is used to indicate the destination location of the requested transmission so that the service request can be accurately identified and processed by the network controller. Therefore, the form of the first node information includes but is not limited to: MAC (Media Access Control) address, IP (Internet Protocol) address, port number, device name or ID, VLAN ID (Virtual LAN Identifier), etc.

[0046] Step S204: determine a plurality of intermediate NEPs between the source control domain network and the destination control domain network in the service request.

[0047] Specifically, the packet OTN network serves as a service bearing platform, which can be used in cross-layer services according to Figure 3 The two-layer network structure shown provides a transmission channel for Ethernet. The two-layer network structure includes: Ethernet (ETH) layer network and ODUk (Optical channel Data Unit) layer network. In addition, since the multi-domain optical transport network is composed of multiple control domain networks to form different control domains, these control domains are independent of each other, and each domain is connected and interconnected through inter-domain links. The network equipment in a single domain is provided by different manufacturers and integrated management and control is implemented, such as Figure 4 As shown, the control domain corresponding to each manufacturer includes 4 network elements (NE). For ease of understanding, the above principle can be used to form Figure 5 The multi-layer and multi-domain resource abstraction model shown in the figure, in which a control domain network or several physical nodes are abstracted into a virtual node (Node), which can be recursively included, and the virtual nodes (Node) can be connected through virtual links (Link), and the virtual links (Link) are abstracted from physical links. Each virtual link can also be an abstraction of several physical links.

[0048] In the technical solution provided in step S204, the collaborative controller can regard the network topology of the source control domain network, the destination control domain network and the intermediate control domain network between the source control domain network and the destination control domain as a large node through abstract modeling, and each large node includes multiple network elements, each network element includes multiple ETH_NEPs and multiple ODU_NEPs, and the ETH_NEPs and ODU_NEPs are connected through Transitional Links. Therefore, the multiple intermediate NEPs between the starting Ethernet NEP and the terminating Ethernet NEP include: the non-starting Ethernet NEP and the first ODU_NEP in the source control domain network, the second ODU_NEP in the intermediate control domain network, and the non-terminating Ethernet NEP and the third ODU_NEP in the destination control domain network.

[0049] It should be noted that, since each device is proposed by a different manufacturer, the mapping scheme from ODU_NEP to ETH_NEP can be one-to-one or one-to-many.

[0050] Step S206: construct a topology matrix at least according to the plurality of intermediate NEPs, and determine a target transmission link that satisfies preset constraints and has the lowest link cost according to the topology matrix.

[0051] In the technical solution provided in step S206, when performing service routing, there are two implementation methods: self-allocation by the domain controller or collaborative controller. Among them, self-allocation by the domain controller means that the domain controller with autonomous selection rights can choose to associate with ODU_NEP according to the device resource situation to maximize the optimization of resource allocation; and when the collaborative controller specifies that the ODU_NEP corresponding to ETH_NEP is specified by the collaborative controller when establishing the service, the premise is that the two specified NEPs must be located on the same Transitional Link. At this time, the collaborative controller has the initiative and can establish a service transmission link on demand. The embodiment of this application mainly introduces the establishment of a service transmission link on demand by the collaborative controller.

[0052] Specifically, the collaborative controller can construct a topology matrix based on at least multiple intermediate NEPs, where the topology matrix is ​​used to reflect the connection status of the links between each NEP; then, by analyzing the topology matrix, the optimal intermediate NEP between the source control domain network and the destination control domain network that meets the preset constraints and has the lowest link cost is selected to establish an inter-layer link (i.e., the target transmission link), thereby forming an inter-layer channel and realizing cross-layer routing.

[0053] Step S208: Routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the target control domain network according to the target transmission link.

[0054] In the technical solution provided in step S208, the collaborative controller routes the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination domain network according to the determined optimal transmission link, thereby ensuring that the service request can cross multiple layers of networks and multiple control domains to achieve end-to-end service transmission.

[0055] The above method of this embodiment is further introduced below.

[0056] As an optional implementation, in the technical solution provided in the above step S206, the collaborative controller can use a global optimization algorithm to determine the target transmission link, wherein the global optimization is to calculate the optimal transmission path between the starting Ethernet NEP and the terminating Ethernet NEP for the entire network. This can be specifically achieved by the following steps:

[0057] Step S11 , constructing a first topology matrix with a starting Ethernet NEP, a plurality of intermediate NEPs and a terminating Ethernet NEP as rows and columns, and with link costs of sub-links between NEPs corresponding to each row and each column as matrix elements.

[0058] In the technical solution provided in the above step S11, the above first topological matrix is ​​recorded as M(m×m), where m represents the total number of NEPs. ij represents the link cost of the sub-link between the NEP corresponding to the i-th row and the NEP corresponding to the j-th column. It should be noted that the link cost of the sub-links between the NEPs in the same network element (NE) is zero. ij = 0, and if there is no sublink between the NEP corresponding to the i-th row and the NEP corresponding to the j-th column, then M ij =∞.

[0059] Step S12: Analyze the first topology matrix using the Dijkstra algorithm to obtain a first transmission link that satisfies the constraint conditions and has the lowest link cost, and use the first transmission link as the target transmission link.

[0060] The technical solution provided in the above step S12 can be understood as: first pre-processing the first topology matrix using various constraints to screen out NEPs that meet various constraints, and reconstructing the first topology matrix, and using the Dijkstra algorithm to analyze the reconstructed first topology matrix, and comprehensively considering various factors in the process of path calculation to find the first transmission link with the lowest link cost, and use the first transmission link as the target transmission link to be determined, thereby reducing the business pressure of the link to a certain extent and achieving balanced link load.

[0061] For example, Figure 6 is a schematic diagram of the principle of an optional global optimal algorithm according to an embodiment of the present application, such as Figure 6 For ease of understanding, we can Figure 6 The route shown is converted to Figure 7 The network topology shown in the figure can be expressed as G(V,E,w), where V represents the set of domains, E represents the set of NEPs in the domain, and w represents the link cost between NEPs, that is, {d distance, res remaining resources, ratio resource occupancy rate}. Then, the calculation of the end-to-end routing across domains can be transformed into the calculation of the optimal path between two nodes in the topology graph. The shortest link between node A in domain A and node C in domain C can be obtained through the Dijkstra algorithm.

[0062] The above constraint conditions include at least one of the following: the sum of the link distances of each sub-link is less than a preset first threshold, the sum of the link resource utilization rates of each sub-link is less than a preset second threshold, the sum of the hop counts of each sub-link is less than a preset third threshold, and the link status of each sub-link is normal. The above link cost is the weighted average sum of the values ​​of the sub-links on the preset link evaluation dimensions, and the link evaluation dimensions include but are not limited to: link distance (i.e., the physical distance between two NEPs), link resource utilization rate (i.e., the ratio of the amount of resources used by the link to the total amount of resources of the link), hop count (i.e., the number of links spanned by the sub-path between two NEPs), link status, etc.

[0063] As another optional implementation, in the technical solution provided in the above step S206, the collaborative controller can also use a local optimization algorithm to determine the target transmission link, wherein the local optimum only needs to be calculated based on the inter-domain link. This can be achieved specifically through the following steps:

[0064] Step S21: a non-initial Ethernet NEP or a first ODU_NEP in the source control domain network is used as the initial NEP in the source control domain network, and a non-termination Ethernet NEP or a third ODU NEP in the destination control domain network is used as the termination NEP in the source control domain network.

[0065] The technical solution provided in the above step S21 can be understood as: a virtual node is abstracted in the center of the source control domain network and the target control domain network as the starting point (starting NEP) and the end point (terminating NEP) of the target link to be solved, wherein the selection criteria are: the link cost of the sublink between the starting NEP and the starting Ethernet NEP, and the link cost of the sublink between the terminating NEP and the terminating Ethernet NEP are both less than the preset threshold value, such as the minimum value ε (ε>0). Therefore, the starting point of the target link to be solved can be a non-starting Ethernet NEP or the first ODU_NEP in the source control domain network, and the end point of the target link to be solved can be a non-terminating Ethernet NEP or the third ODU_NEP in the target control domain network, thereby avoiding the problem of how to select the starting point and the end point from the boundary nodes of the domain.

[0066] Step S22, constructing a second topology matrix with the starting NEP, the ending NEP, and the middle NEP between the starting NEP and the ending NEP as rows and columns, and with the link costs of the sub-links between the NEPs corresponding to each row and each column as matrix elements.

[0067] In the technical solution provided in the above step S22, the above second topology matrix is ​​recorded as N(n×n), where n represents the total number of NEPs between the starting point and the end point of the target link to be solved. Then N ij represents the link cost of the sub-link between the NEP corresponding to the i-th row and the NEP corresponding to the j-th column. It should be noted that the link cost of the sub-link between the NEPs in the same network element (NE) is zero. ij =0.

[0068] Step S23: Analyze the second topology matrix using the Dijkstra algorithm to obtain a second transmission link that satisfies the constraint conditions and minimizes the link cost.

[0069] The technical solution provided by the above step S23 can be understood as first preprocessing the second topology matrix using the above constraints to screen out NEPs that meet the above constraints, and reconstructing the second topology matrix, and using the Dijkstra algorithm to analyze the reconstructed second topology matrix, and comprehensively considering various factors in the process of path calculation to find the second transmission link with the lowest link cost, thereby reducing the business pressure of the link to a certain extent and achieving balanced link load.

[0070] Step S24, determining a third transmission link between the starting Ethernet NEP and the starting NEP and a fourth transmission link between the terminating NEP and the terminating Ethernet NEP, and forming a target transmission link by the third transmission link, the second transmission link and the fourth transmission link.

[0071] For example, Figure 8 is a schematic diagram of an optional multi-layer multi-domain local optimal routing according to an embodiment of the present application, such as Figure 8 As shown in Figure 2, A and Z are the source node and destination node of the actual path calculation, for the sake of convenience, we can directly let A ′ =A,Z ′ = Z, then when constructing the second topology matrix, the collection of NEPs is divided into the following two steps: (1) obtaining all NEPs at both ends of all inter-domain links (i.e., multiple intermediate NEPs); (2) adding source node A and sink node Z, so that the path calculation result is the transmission link that actually needs to be determined. Similarly, Figure 8 The route shown is converted to Figure 7 The network topology diagram shown is convenient for subsequent analysis using the Dijkstra algorithm to quickly find the shortest link between node A in domain A and node C in domain C.

[0072] In addition, in the above steps S11-S12 and steps S22-S24, the above link cost is the weighted average sum of the values ​​of the sub-links in the preset link evaluation dimensions, and the link evaluation dimensions include at least one of the following: link distance, link resource utilization, number of hops, and link status.

[0073] Taking the link evaluation dimensions including link distance dist and link resource utilization rate rsrc = used resources / total resources as an example, the link cost of each sub-link can be expressed as: cost = α*dist + β*rsrc, where α and β represent the proportional factors of link distance dist and link resource utilization rate rsrc, respectively, so α+β = 1. Compared with considering only a single dimension, this can largely avoid excessive concentration of services on a certain path, thereby greatly improving the success rate of service establishment when the service volume is large.

[0074] It should be noted that when using the values ​​of sub-links in multiple link evaluation dimensions to determine the link cost, it is necessary to approximate the values ​​of the sub-links in each link evaluation dimension so that the two values ​​are in the same order of magnitude to avoid the value difference being too large so that one side has no effect.

[0075] As an optional implementation, in the technical solution provided in the above step S208, the collaborative controller may construct a topology matrix by the following method and may route the service request by the following method, including:

[0076] Step S2081, determining the control domain network to which each NEP on the target transmission link belongs, and obtaining the transmission sub-links in each control domain network.

[0077] That is to say, each NEP on the target transmission link is divided into its own control domain network to form a transmission sub-link in each control domain network. The types of control domain networks include: source control domain network, destination control domain network, and intermediate control domain network.

[0078] For example, for Figure 6 As for the target transmission link shown, each node on the target transmission link can be divided into corresponding control domains A, B, and C to obtain transmission sub-links in each control domain network A, B, and C: {A, a1, a2}, {b1, b2}, {c, Z}.

[0079] And for Figure 8 For the target transmission link shown, each node on the target transmission link can be divided into corresponding control domains A, B, and C to obtain transmission sub-links in each control domain network A, B, and C: {A, a}, {b1, b2}, {c, Z}.

[0080] Step S2082: adjust the service request according to the type of the control domain network, and route the adjusted service request to the terminating Ethernet NEP in the destination control domain network according to the transmission sub-links in each control domain network.

[0081] In a multi-layer and multi-domain business scenario, all services flow in from the ETH layer, are transported through the ODU layer, and finally flow out from the ETH layer. Therefore, both the source control domain network and the destination control domain network need to carry ETH services, so two-layer connection requests need to be sent in both the source control domain network and the destination control domain network.

[0082] Therefore, when the collaborative controller performs cross-domain routing on the service request, in order to enable it to obtain all network element information (that is, how to route from the starting Ethernet NEP to the terminating Ethernet NEP) and obtain full control, the service request can be adjusted as follows:

[0083] For the transmission sub-link within the source control domain network, in the process of routing the service request from the starting Ethernet NEP to the non-starting Ethernet NEP, the second node information of the starting Ethernet NEP and the third node information of the non-starting Ethernet NEP are added to the service request; in the process of routing the service request from the current first ODU_NEP within the source control domain network to the next first ODU_NEP, the third node information of the non-starting Ethernet NEP, the fourth node information of the current first ODU_NEP and the fifth node information of the next first ODU_NEP are added to the service request.

[0084] For the transmission sub-link in the intermediate control domain network, in the process of routing the service request from the current second ODU_NEP to the next second ODU_NEP, the sixth node information of the current second ODU_NEP and the seventh node information of the next second ODU_NEP are added to the service request;

[0085] For the transmission sub-link within the destination control domain network, in the process of routing the service request from the current third ODU_NEP within the destination control domain network to the next third ODU_NEP, the eighth node information of the current third ODU_NEP and the ninth node information of the next third ODU_NEP are added to the service request; in the process of routing the service request from the non-termination Ethernet NEP to the termination Ethernet NEP, the first node information of the termination Ethernet NEP and the tenth node information of the non-termination Ethernet NEP are added to the service request.

[0086] by Fig. 9 Taking the multi-layer multi-domain optical transport network shown as an example, ETH_NEP1 in the network element NE1 in the large node responsible for manufacturer A is used as the starting Ethernet NEP in the source control domain network, and ETH_NEP1 in the network element NE4 in the large node responsible for manufacturer C is used as the terminating Ethernet NEP in the destination control domain network.

[0087] Then, when the network element NE1 in the large node that manufacturer A is responsible for carries the ETH service, when the starting Ethernet NEP—ETH_NEP1 in the source control domain network sends the service request to the starting Ethernet NEP—ETH_NEP 2, it is necessary to add the following information to the request message: {NEA1.ETH_NEP1, NEA1.ETH_NEP2}, where ETH_NEP2 represents the identification information of ETH_NEP. When the first ODU_NEP—ODU_NEP1 in the source control domain network sends the service request to the next first ODU_NEP—ODU_NEP2, it is necessary to add the following information to the request message: {NEA1.ETH_NEP2, NEA1.ODU_NEP1, NEA4.ODU_NEP1}. When ODU_NEP2 of network element NE4 in the large node responsible for manufacturer A sends the service request to ODU_NEP1 of network element NE1 in the large node responsible for manufacturer B, identification information {NEA4.ODU_NEP2, NEB1.ODU_NEP1} needs to be added to the request message.

[0088] Based on the scheme defined in the above steps S202 to S208, it can be known that in the embodiment, the collaborative controller constructs a topology matrix based on multiple intermediate NEPs between the starting Ethernet NEP in the source control domain network and the terminating Ethernet NEP in the destination control domain network, and uses a global optimal algorithm or a local optimal algorithm to obtain a target transmission link with optimal (i.e., lowest link cost) performance in multiple link evaluation dimensions based on preset constraints (i.e., satisfying preset link requirements and path calculation conditions), thereby improving resource utilization, reducing link blocking rate, and greatly improving the network's carrying capacity and service establishment success rate. Efficient and balanced management and transmission of cross-domain services in a complex network environment are achieved, significantly improving the utilization efficiency and service quality of network resources, and providing operators and users with a more stable and faster network experience.

[0089] Example 2

[0090] Based on Embodiment 1 of the present application, an embodiment of a routing device for a multi-layer multi-domain optical transmission network is also provided, and when the device is running, the routing method for the multi-layer multi-domain optical transmission network of the above embodiment is executed. Fig.10 is a schematic structural diagram of an optional routing device of a multi-layer multi-domain optical transmission network according to an embodiment of the present application, such as Fig.10 As shown, the routing device of the multi-layer multi-domain optical transport network at least includes: a receiving module 102, a first determining module 104, a second determining module 106 and a routing module 108, wherein:

[0091] The receiving module 102 is used to receive a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network;

[0092] The first determining module 104 is configured to determine a plurality of intermediate NEPs between a source control domain network and a destination control domain network in a service request, wherein the intermediate NEPs include at least one of the following: a non-initial Ethernet NEP and a first ODU NEP in the source control domain network, a second ODU NEP in an intermediate control domain network between the source control domain network and the destination control domain, a non-terminating Ethernet NEP and a third ODU NEP in the destination control domain network;

[0093] A second determination module 106 is used to construct a topology matrix according to the starting Ethernet NEP, the plurality of intermediate NEPs, and the terminating Ethernet NEP, and determine a target transmission link that satisfies a preset constraint condition and has the lowest link cost according to the topology matrix;

[0094] The routing module 108 is used to route the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the target control domain network according to the target transmission link.

[0095] It should be noted that the various modules in the routing device of the above-mentioned multi-layer and multi-domain optical transmission network can be program modules (for example, a set of program instructions to implement a certain specific function) or hardware modules. For the latter, it can be expressed in the following forms, but is not limited to this: the expression form of each of the above-mentioned modules is a processor, or the functions of each of the above-mentioned modules are implemented by a processor.

[0096] Example 3

[0097] According to an embodiment of the present application, a non-volatile storage medium is also provided, in which a program is stored, wherein when the program is running, the device where the non-volatile storage medium is located is controlled to execute the routing method of the multi-layer and multi-domain optical transmission network in Example 1.

[0098] Optionally, the device where the non-volatile storage medium is located implements the following steps by running the program: receiving a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; determining multiple intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the multiple intermediate NEPs include: a non-starting Ethernet NEP and a first ODU_NEP in the source control domain network, a second ODU_NEP in the intermediate control domain network between the source control domain network and the destination control domain, and a non-terminating Ethernet NEP and a third ODU_NEP in the destination control domain network; constructing a topology matrix based on at least multiple intermediate NEPs, and determining a target transmission link that meets preset constraints and has the lowest link cost based on the topology matrix; and routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link.

[0099] According to an embodiment of the present application, a computer program product is also provided, which includes a stored computer program, wherein when the computer program is executed by a processor, the routing method of the multi-layer multi-domain optical transmission network in Example 1 is implemented.

[0100] Optionally, the computer program executes the following steps: receiving a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; determining multiple intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the multiple intermediate NEPs include: a non-starting Ethernet NEP and a first ODU_NEP in the source control domain network, a second ODU_NEP in an intermediate control domain network between the source control domain network and the destination control domain, and a non-terminating Ethernet NEP and a third ODU_NEP in the destination control domain network; constructing a topology matrix based on at least the multiple intermediate NEPs, and determining a target transmission link that meets preset constraints and has the lowest link cost based on the topology matrix; and routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link.

[0101] According to an embodiment of the present application, a processor is further provided, which is used to run a program, wherein the routing method of the multi-layer and multi-domain optical transmission network in Example 1 is executed when the program is run.

[0102] Optionally, when the program is running, the following steps are executed: receiving a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; determining multiple intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the multiple intermediate NEPs include: a non-starting Ethernet NEP and a first ODU_NEP in the source control domain network, a second ODU_NEP in an intermediate control domain network between the source control domain network and the destination control domain, and a non-terminating Ethernet NEP and a third ODU_NEP in the destination control domain network; constructing a topology matrix based on at least multiple intermediate NEPs, and determining a target transmission link that satisfies preset constraints and minimizes link costs based on the topology matrix; and routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link.

[0103] According to an embodiment of the present application, an electronic device is also provided, wherein the electronic device includes one or more processors; a memory for storing one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors are implemented to run the programs, wherein the program is configured to execute the routing method of the multi-layer and multi-domain optical transmission network in the above-mentioned embodiment 1 when running.

[0104] Optionally, the processor is configured to execute the following steps through a computer program: receiving a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; determining multiple intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the multiple intermediate NEPs include: a non-starting Ethernet NEP and a first ODU_NEP in the source control domain network, a second ODU_NEP in an intermediate control domain network between the source control domain network and the destination control domain, and a non-terminating Ethernet NEP and a third ODU_NEP in the destination control domain network; constructing a topology matrix based on at least the multiple intermediate NEPs, and determining a target transmission link that meets preset constraints and has the lowest link cost based on the topology matrix; and routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link.

[0105] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0106] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0107] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0108] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0109] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0110] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the relevant technology or all or part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of each embodiment method of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, RandomAccess Memory), mobile hard disk, disk or optical disk, etc. Various media that can store program codes.

[0111] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A routing method for a multi-layer multi-domain optical transport network, characterized in that: include: Receiving a service request initiated by a starting Ethernet network element node NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; Determine a plurality of intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the plurality of intermediate NEPs include: a non-initial Ethernet NEP and a first optical path data unit ODU_NEP in the source control domain network, a second ODU_NEP in the intermediate control domain network between the source control domain network and the destination control domain, and a non-terminating Ethernet NEP and a third ODU_NEP in the destination control domain network; At least construct a topology matrix based on the multiple intermediate NEPs, and determine a target transmission link that satisfies preset constraints and has the lowest link cost based on the topology matrix; The service request is routed from the starting Ethernet NEP to a terminating Ethernet NEP in the destination control domain network according to the target transmission link.

2. The method according to claim 1, characterized in that At least building a topology matrix based on the plurality of intermediate NEPs, and determining a target transmission link that satisfies a preset constraint and minimizes the link cost based on the topology matrix, including: Constructing a first topology matrix by taking the starting Ethernet NEP, the multiple intermediate NEPs and the terminating Ethernet NEP as rows and columns, and taking the link costs of sub-links between the NEPs corresponding to each row and each column as matrix elements; The first topology matrix is ​​analyzed by using the Dijkstra algorithm to obtain a first transmission link that satisfies the constraint condition and minimizes the link cost, and the first transmission link is used as the target transmission link.

3. The method according to claim 1, characterized in that At least building a topology matrix based on the plurality of intermediate NEPs, and determining a target transmission link that satisfies a preset constraint and minimizes the link cost based on the topology matrix, including: A non-starting Ethernet NEP or a first ODU_NEP in the source control domain network is used as a starting NEP in the source control domain network, and a non-terminating Ethernet NEP or a third ODU_NEP in the destination control domain network is used as a terminating NEP in the source control domain network, wherein a link cost of a sublink between the starting NEP and the starting Ethernet NEP and a link cost of a sublink between the terminating NEP and the terminating Ethernet NEP are both less than a preset threshold value; Constructing a second topology matrix by taking the starting NEP, the ending NEP, and the intermediate NEP between the starting NEP and the ending NEP as rows and columns, and taking the link costs of the sub-links between the NEPs corresponding to each row and each column as matrix elements; Analyzing the second topology matrix by using Dijkstra algorithm to obtain a second transmission link that satisfies the constraint condition and minimizes the link cost; A third transmission link between the starting Ethernet NEP and the starting NEP and a fourth transmission link between the terminating NEP and the terminating Ethernet NEP are determined, and the target transmission link is composed of the third transmission link, the second transmission link and the fourth transmission link.

4. The method according to any one of claims 2 or 3, characterized in that The link cost is the weighted average sum of the values ​​of the sub-links in preset link evaluation dimensions, and the link evaluation dimensions include at least one of the following: link distance, link resource utilization, number of hops, and link status.

5. The method according to any one of claims 2 or 3, characterized in that: The constraint conditions include at least one of the following: the sum of the link distances of the sub-links is less than a preset first threshold, the sum of the link resource utilization rates of the sub-links is less than a preset second threshold, the sum of the hop counts of the sub-links is less than a preset third threshold, and the link status of the sub-links is normal.

6. The method according to claim 1, characterized in that Routing the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link includes: Determine the control domain network to which each NEP on the target transmission link belongs, and obtain the transmission sub-links in each of the control domain networks, wherein the types of the control domain networks include: the source control domain network, the destination control domain network, and the intermediate control domain network; The service request is adjusted according to the type of the control domain network, and the adjusted service request is routed to a terminating Ethernet NEP in the destination control domain network according to the transmission sub-links in each of the control domain networks.

7. The method according to claim 6, characterized in that Adjusting the service request to be routed according to the type of the control domain network includes: For the transmission sub-link in the source control domain network, in the process of routing the service request from the starting Ethernet NEP to the non-starting Ethernet NEP, the second node information of the starting Ethernet NEP and the third node information of the non-starting Ethernet NEP are added to the service request; in the process of routing the service request from the current first ODU_NEP in the source control domain network to the next first ODU_NEP, the third node information of the non-starting Ethernet NEP, the fourth node information of the current first ODU_NEP and the fifth node information of the next first ODU_NEP are added to the service request; For the transmission sub-link in the intermediate control domain network, in the process of routing the service request from the current second ODU_NEP in the intermediate control domain network to the next second ODU_NEP, adding the sixth node information of the current second ODU_NEP and the seventh node information of the next second ODU_NEP in the service request; For the transmission sub-link within the destination control domain network, in the process of routing the service request from the current third ODU_NEP within the destination control domain network to the next third ODU_NEP, the eighth node information of the current third ODU_NEP and the ninth node information of the next third ODU_NEP are added to the service request; in the process of routing the service request from the non-termination Ethernet NEP to the termination Ethernet NEP, the first node information of the termination Ethernet NEP and the tenth node information of the non-termination Ethernet NEP are added to the service request.

8. A routing device for a multi-layer multi-domain optical transport network, characterized in that: include: A receiving module, configured to receive a service request initiated by a starting Ethernet NEP in a source control domain network, wherein the service request carries at least first node information of a terminating Ethernet NEP in a destination control domain network; A first determining module is configured to determine a plurality of intermediate NEPs between the source control domain network and the destination control domain network in the service request, wherein the intermediate NEPs include at least one of the following: a non-initial Ethernet NEP and a first ODU NEP in the source control domain network, a second ODU NEP in the intermediate control domain network between the source control domain network and the destination control domain, and a non-terminating Ethernet NEP and a third ODU NEP in the destination control domain network; A second determination module is used to construct a topology matrix according to a starting Ethernet NEP, a plurality of intermediate NEPs, and a terminating Ethernet NEP, and determine a target transmission link that satisfies a preset constraint condition and has the lowest link cost according to the topology matrix; A routing module is used to route the service request from the starting Ethernet NEP to the terminating Ethernet NEP in the destination control domain network according to the target transmission link.

9. A computer program product, characterized in that include: A computer program, wherein when the computer program is executed by a processor, the routing method of the multi-layer and multi-domain optical transmission network according to any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that: include: A memory and a processor, wherein the processor is used to run a program stored in the memory, wherein the program, when running, executes the routing method for a multi-layer and multi-domain optical transmission network as claimed in any one of claims 1 to 7.

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