Quantum and classical coexistence routing and spectrum allocation optimization method and related device

Abstract

The invention belongs to the field of quantum key distribution networks, and discloses a quantum and classic coexistence routing and spectrum allocation optimization method and a related device, and the method comprises the steps: dividing service requests into different types, adopting a differential routing strategy, and selecting an optimal path for transmission in combination with a frequency slot resource state; in the transmission process, the protection interval between the quantum signal and the classic signal is dynamically adjusted based on the remaining amount of the key pool, the generation rate and the consumption rate, and frequency slot distribution is optimized through rerouting or interval adjustment when routing fails or keys are insufficient; by adopting the method, spectrum conflicts can be effectively relieved, key supply and demand can be balanced, the resource cooperative scheduling capability can be improved, the security service blocking rate can be obviously reduced, the key utilization efficiency can be improved, and the link resource waste can be reduced, so that the elastic deployment requirement of the large-scale quantum-classical fusion network can be supported.

Description

Technical Field

[0001] This invention belongs to the field of quantum key distribution network technology, and particularly relates to a routing and spectrum allocation optimization method and related apparatus for quantum and classical coexistence. Background Technology

[0002] As optical communication networks continue to evolve towards higher transmission bandwidth and greater security, quantum key distribution (QKD) has become a key technological support for ensuring the security of high-speed core services. Within the QKD technology system, continuous variable quantum key distribution (CV-QKD), with its high compatibility with traditional optical communication in modulation methods, receiver structures, and wavelength multiplexing methods, exhibits superior existing network integration capabilities compared to discrete variable quantum key distribution (DV-QKD). It possesses significant advantages in industrialization and engineering deployment, becoming an important candidate technology for building quantum-classical integrated networks. Currently, the core requirement of optical communication networks focuses on achieving the coordinated operation of efficient classical service transmission and quantum security assurance. The technical characteristics of CV-QKD make it a crucial link between the two, and the optimization and improvement of related technologies are of great significance for promoting the network security upgrade of optical communication networks.

[0003] However, the application and promotion of CV-QKD technology still faces multiple bottlenecks. On the one hand, CV-QKD quantum signals are extremely sensitive to classical optical noise. When transmitted on the same fiber as high-power classical signals, they are easily affected by noise coupling such as spontaneous Raman scattering, four-wave mixing, and adjacent channel crosstalk, leading to quantum signal degradation, a significant reduction in key rate, or even interruption of key generation. At the same time, traditional optical network spectrum scheduling mechanisms only consider the bandwidth requirements and frequency slot continuity of classical services, without considering the noise tolerance and isolation requirements of quantum signals, causing serious spectrum conflict problems. On the other hand, the key pools of existing CV-QKD systems mostly adopt a static configuration mode, which cannot be dynamically adjusted according to service requirements, link status, and quantum signal changes. This leads to a supply-demand imbalance problem where the key pool is quickly exhausted when the link is under high load, and key resources are idle and wasted when the link is under low load. In addition, existing co-fiber and co-network solutions generally lack a collaborative optimization mechanism for spectrum resources and key resources. Routing selection still focuses on distance or link cost as the core consideration, without incorporating key factors such as the remaining key quantity and dynamic adjustment of guard band, resulting in prominent problems such as high security service blocking rate, low key utilization efficiency, and waste of link resources.

[0004] It is evident that existing control optimization methods suffer from problems such as spectrum conflicts, key pool supply and demand imbalances, and lack of resource coordination and scheduling when CV-QKD and classical optical networks share the same fiber and network, making it difficult to meet the deployment requirements of large-scale, flexible quantum-classical fusion networks. Summary of the Invention

[0005] The purpose of this invention is to provide a routing and spectrum allocation optimization method and related apparatus for the coexistence of quantum and classical networks. This method can solve the problems of spectrum conflict, key pool supply and demand imbalance and lack of resource coordination scheduling when CV-QKD and classical optical networks share the same fiber and network in existing control optimization methods, thereby meeting the deployment requirements of large-scale, flexible quantum-classical integrated networks.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A routing and spectrum allocation optimization method for the coexistence of quantum and classical approaches includes: The received service requests are distinguished by service type, and a differentiated routing calculation strategy is adopted for different service types. The optimal path is selected in combination with the frequency slot resource status so as to transmit services according to the optimal path. During service transmission, the protection interval is dynamically adjusted based on the remaining amount of the key pool, the generation rate, and the consumption rate. When the route calculation fails or the remaining amount of the key pool is insufficient, the allocation of frequency slot resources is optimized by re-route calculation or adjustment of the protection interval. After the service request is transmitted, a frequency slot release command is issued based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of the frequency slot resources and the remaining amount of the key pool of each service node.

[0007] Furthermore, before distinguishing the received service requests by service type, adopting differentiated routing calculation strategies for different service types, and selecting the optimal path based on the frequency slot resource status to transmit services according to the optimal path, the process also includes initializing and configuring the frequency slot resources, guard interval, and key pool of the network environment. The specific steps are as follows: The low-frequency band of the optical spectrum is divided into classical signal frequency slot regions, and the high-frequency band is divided into quantum signal frequency slot regions. Fixed frequency slots are reserved in both types of frequency slot regions for continuous signal transmission. A fixed-bandwidth guard interval is set in the intermediate frequency band between the highest frequency gap of the classical signal and the lowest frequency gap of the quantum signal. The guard interval is a dynamically movable vacant frequency gap area, and the position of the guard interval is adjusted in real time according to the key pool status and business load. A key pool is built for the nodes at both ends of the link, a unified initial key quantity and capacity limit are set, a first-in-first-out mechanism is used to manage the keys, and warning thresholds and emergency thresholds are configured for the key pool.

[0008] Furthermore, the step of distinguishing received service requests by service type, employing differentiated routing calculation strategies for different service types, and selecting the optimal path based on the frequency slot resource status to transmit services according to the optimal path includes: Receive service requests, break down the service requests, and distinguish the service types; wherein, the service types include classic services and security services; If the service type is classic service, then extract the source and destination nodes and bandwidth requirement parameters; If the service type is security service, extract the source and destination nodes, bandwidth requirements, and key quantity requirements. Security services also occupy two classic channels simultaneously: one classic channel is the key path used to apply for the end-to-end global key, and the other classic channel is the classic path used to transmit encrypted data. The k-shortest path algorithm combined with the frequency slot resource status is used to select the optimal path for classic services; the k-shortest path algorithm combined with the frequency slot resource status is also used to select the optimal path for security services; differentiated routing calculation strategies are adopted for classic services and security services. Service transmission is performed according to the selected optimal path.

[0009] Furthermore, the step of using the k-shortest path algorithm combined with the frequency slot resource status to select the optimal path for classic services includes: The k-shortest path algorithm is called to calculate multiple candidate paths with hop count as weight. Based on the principle of frequency slot consistency, the path that meets the bandwidth requirements and has the lowest continuous idle frequency band is selected, and routing and frequency slot allocation instructions are issued. If the allocation fails, rerouting is performed or the protection interval is adjusted to optimize the allocation of frequency slot resources.

[0010] Furthermore, the step of using the k-shortest path algorithm combined with the frequency slot resource status to select the optimal path for security services includes: The k-shortest path algorithm is called to calculate multiple candidate paths with hop count as weight. The path with the strongest key supply capability is selected as the key path. Based on the frequency slot consistency principle, the path that meets the bandwidth requirements and has the lowest continuous idle frequency slot is selected as the classic path. If both paths meet the requirements, resources are allocated; otherwise, the service is blocked.

[0011] Furthermore, the dynamic adjustment of the protection interval during service transmission based on the remaining amount of the key pool, the generation rate, and the consumption rate includes: If the remaining key quantity is detected to drop to the warning threshold and the key consumption rate exceeds the generation rate for a preset time, the protection interval will be moved to a lower frequency direction; if it occupies a classic channel that is currently transmitting services, rerouting calculation or adjustment of the protection interval will be performed to optimize the allocation of frequency slot resources. When the remaining key amount drops to the emergency threshold, the protection interval is moved directly. If it occupies the in-transmission classical channel, the signal is cut off and the service is blocked. When the remaining key amount rises back to the warning threshold and the generation rate exceeds the consumption rate for a preset time, the protection interval is reset to the initial state.

[0012] Furthermore, the optimization of frequency slot resource allocation by re-calculating or adjusting the guard interval when routing calculation fails or the remaining key pool is insufficient includes: When the route calculation fails or the key pool is insufficient, the route calculation is restarted from the path with the fewest overlapping links in the alternative paths of the k-shortest path algorithm to find an idle path and frequency slot. If an available frequency slot exists, it is allocated to the current service; otherwise, the service is blocked. When a protection interval is moved, the distance the protection interval moves to a lower frequency is determined by the number of link boundaries. If it conflicts with the frequency slot of the classic service being transmitted, a rerouting calculation is performed. If the rerouting fails, the service is blocked.

[0013] A routing and spectrum allocation optimization system that allows for the coexistence of quantum and classical technologies includes: The routing module is used to distinguish the received service requests by service type, adopt differentiated routing calculation strategies for different service types, and select the optimal path in combination with the frequency slot resource status so as to transmit services according to the optimal path. The dynamic adjustment module is used to dynamically adjust the protection interval based on the remaining amount of the key pool, the generation rate, and the consumption rate during service transmission; when the route calculation fails or the remaining amount of the key pool is insufficient, the allocation of frequency slot resources is optimized by re-route calculation or adjusting the protection interval. The frequency slot release module is used to issue a frequency slot release command after the service request has been transmitted, based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of the frequency slot resources and the remaining amount of the key pool of each service node.

[0014] A routing and spectrum allocation optimization device that allows for the coexistence of quantum and classical technologies, comprising: Memory, used to store computer programs; A processor is used to implement the steps of the above-described routing and spectrum allocation optimization method for quantum and classical coexistence when executing the computer program.

[0015] A computer-readable storage medium storing a computer program, which, when executed by a processor, is used to implement the steps of the above-described routing and spectrum allocation optimization method for quantum and classical coexistence.

[0016] Compared with existing technologies, the present invention has the following beneficial effects: This invention provides a routing and spectrum allocation optimization method for quantum and classical coexistence. It distinguishes service requests into different types and employs differentiated routing strategies, selecting the optimal path for transmission based on the frequency slot resource status. During transmission, the protection interval between quantum and classical signals is dynamically adjusted based on the remaining key pool amount, generation rate, and consumption rate. In case of routing failure or insufficient keys, frequency slot allocation is optimized through rerouting or interval adjustment. After service completion, the occupied frequency slot resources are released based on termination information, and the resource status and key pool are updated. The differentiated routing strategy optimizes path selection for the high noise sensitivity of quantum services, reducing interference such as spontaneous Raman scattering. The dynamic protection interval adjustment adaptively isolates noise based on the real-time key pool status, avoiding key supply and demand imbalances caused by static configuration. The rerouting mechanism provides alternative solutions in case of resource conflicts, ensuring service continuity. The resource release and update mechanism collaboratively maintains the efficient circulation of spectrum and key resources. This method effectively alleviates spectrum conflicts, balances key supply and demand, improves resource collaborative scheduling capabilities, significantly reduces the blocking rate of secure services, improves key utilization efficiency, and reduces link resource waste, thereby supporting the elastic deployment requirements of large-scale quantum-classical integrated networks. Attached Figure Description

[0017] Figure 1 A flowchart illustrating the implementation of a routing and spectrum allocation optimization method for quantum and classical coexistence provided in this embodiment of the invention; Figure 2 The following is a schematic diagram of an example of a routing and spectrum allocation optimization method using quantum and classical coexistence provided in an embodiment of the present invention; wherein, (a) is a schematic diagram of a four-node network topology; (b) is a schematic diagram of guard interval adjustment; and (c) is a schematic diagram of the frequency slot occupancy of each link. Figure 3 A flowchart of a routing and spectrum allocation optimization method for quantum and classical coexistence provided by the present invention; Figure 4 This is a schematic diagram of a routing and spectrum allocation optimization system that allows for the coexistence of quantum and classical technologies, as provided by the present invention. Detailed Implementation

[0018] To facilitate a deeper understanding of the technical solution of this invention, the following explanations are provided for the technical terms: QKD: Quantum Key Distribution is a technology that uses the principles of quantum mechanics to achieve secure key distribution. It can generate theoretically unconditionally secure shared keys between communicating parties, providing security guarantees that cannot be eavesdropped on or cracked for encrypted communication.

[0019] CV-QKD: Continuous Variable Quantum Key Distribution. Quantum key distribution, based on the fundamental principles of quantum mechanics, can generate unconditionally secure keys and is a crucial foundational technology for ensuring future communication security. The main implementation schemes are divided into two categories: discrete variable quantum key distribution and continuous variable quantum key distribution. DV-QKD, based on single-photon encoding and detection, relies on expensive single-photon detectors, is highly sensitive to link loss and system noise, and differs significantly from existing optical networks in modulation format, detection method, and power budget. CV-QKD uses coherent states as quantum signal carriers, encodes information through Gaussian modulation of amplitude and phase, and obtains quantum measurement results using local oscillator coherent detection. It can fully reuse components in existing coherent optical communication, thereby reducing hardware barriers and implementation difficulty. Through high-speed modulation and high-bandwidth coherent detectors, CV-QKD can achieve high secure key rates, and with advancements in digital signal processing and efficient error correction technologies, the overall key throughput of CV-QKD is further improved.

[0020] CV-QKD and Classical Optical Network Coexistence Technology: This technology aims to integrate quantum-secure communication with existing telecommunications infrastructure, enabling large-scale deployment of quantum key distribution systems without the need for dedicated optical fibers. By optimizing wavelength allocation, utilizing the natural filtering capabilities of quantum local oscillators, and finely controlling the transmission power of classical signals, interference from noise such as Raman scattering on quantum signals can be effectively suppressed. Recently, a team has achieved stable coexistence of CV-QKD and a fully loaded C-band classical channel on a 120km optical fiber link with minimal additional filters. Furthermore, using Software Defined Network (SDN) technology, the spectral spacing between the quantum and classical channels can be dynamically adjusted, thereby improving system flexibility and key generation rate. This technology not only retains the high throughput of classical networks but also provides a plug-and-play, low-cost, and large-scale deployment reference model for future quantum-secure networks.

[0021] CV-QKD and Resource Cooperative Management Techniques in Classical Optical Networks: CV QKD and classical optical network resource collaborative management technology focuses on the optimization of wavelength, key, and routing. In terms of bandwidth allocation, wavelength selection switches and wavelength-level scheduling are used to integrate quantum channels into the classical wavelength division multiplexing network, and guard bands are rationally divided to reduce noise introduced by classical signals, thereby ensuring the quality of quantum signals. Regarding key resource allocation, a quantum key pool (QKP) is established to store generated keys, and the key pool status is dynamically monitored by an SDN controller, flexibly allocating and updating keys according to service needs and key supply. In terms of routing, routing paths need to be comprehensively considered from multiple perspectives, including remaining bandwidth resources, key resources, and service load, to improve service request success rates and reduce the risk of key shortages or spectrum conflicts. This collaborative mechanism enables the efficient and stable operation of classical data and quantum signals in a coexisting network, while ensuring key utilization efficiency and network service quality.

[0022] As mentioned in the background section, existing technologies have significant shortcomings in achieving coexistence between CV-QKD and classical optical networks: classical optical network solutions prioritize ensuring the quality of service for traditional services, neglecting the extremely high sensitivity of quantum signals to noise, making it difficult to guarantee the performance of quantum channels. Furthermore, CV-QKD-based networking typically employs static spectrum isolation, with guard intervals that cannot be dynamically adjusted, and key pools are prone to depletion or overflow, lacking cross-link key scheduling and load balancing mechanisms. Existing shared fiber and shared network solutions generally fail to achieve coordinated optimization of spectrum and key resources, with routing selection still primarily based on distance or link cost, without considering the dynamic adjustment of remaining key quantity or guard band. This easily leads to problems such as high security service blocking rates, low key utilization efficiency, and poor link resource utilization, making it difficult to meet the requirements of large-scale, flexible deployment of quantum-classical coexistence networks.

[0023] To achieve the above objectives, this embodiment provides a routing and spectrum allocation optimization method for quantum and classical coexistence. This method designs quantum and classical bandwidth configurations, dynamically adjusts guard intervals, and implements routing strategies based on service requirements to achieve coordinated scheduling of quantum and classical services, thereby improving the key supply capacity and classical service transmission stability of the coexisting network. Specifically, the guard interval setting reduces noise crosstalk from classical signals to quantum signals. Differentiated routing strategies are adopted for the different needs of classical and security services to improve the adaptability of routing paths. Dynamic spectrum allocation optimization is implemented based on service load and key pool status. A tiered adjustment method, prioritizing rerouting buffers and addressing congestion-related urgent adjustments, is proposed to address potential service conflicts during bandwidth adjustment. This ensures the continuity of quantum key distribution, reducing service blocking rates while improving the utilization rate of bandwidth and key resources.

[0024] like Figure 3As shown, this embodiment provides a routing and spectrum allocation optimization method for the coexistence of quantum and classical technologies, including: The received service requests are distinguished by service type, and a differentiated routing calculation strategy is adopted for different service types. The optimal path is selected in combination with the frequency slot resource status so as to transmit services according to the optimal path. During service transmission, the protection interval is dynamically adjusted based on the remaining amount of the key pool, the generation rate, and the consumption rate. When the route calculation fails or the remaining amount of the key pool is insufficient, the allocation of frequency slot resources is optimized by re-route calculation or adjustment of the protection interval. After the service request is transmitted, a frequency slot release command is issued based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of frequency slot resources and the remaining key pool amount of each service node. The current channel is then switched to the target channel to achieve optimized routing and spectrum allocation for both quantum and classical computing.

[0025] The routing and spectrum allocation optimization method for quantum and classical coexistence provided in this embodiment will be further explained below with reference to the accompanying drawings: like Figure 1 As shown, this embodiment provides a routing and spectrum allocation optimization method that combines quantum and classical approaches. This method is applied to the entire SDN controller, which is divided into five major modules: resource initialization module, service route calculation module, guard interval adjustment module, frequency slot allocation optimization module, and resource status update module. This module enables the implementation of the routing and spectrum allocation optimization method that combines quantum and classical approaches provided in this embodiment. The specific steps are as follows: Step 1, Resource Initialization Process, based on resource initialization implementation, includes: Resource initialization is the preparatory phase for network operation. By defining the initial configuration rules for frequency slots, guard intervals, and key pools, it lays the foundation for subsequent service transmission and resource scheduling. The specific steps are as follows: Step 1.1: Fixed frequency slot resource configuration: Classic signal frequency band configuration: Divide the minimum frequency band unit according to the classic service requirements, configure the low frequency band of the optical spectrum as the classic signal frequency band area, and reserve some fixed low frequency bands for continuous classic optical signal transmission to avoid obstruction of basic communication requirements; Quantum signal band configuration: The high-frequency band of the optical spectrum is configured as the quantum signal band region. According to the key generation rate requirements of the CV-QKD system, continuous and independent band blocks are allocated, and some fixed high-frequency bands are reserved for continuous quantum signal transmission. After initialization, the quantum channel is activated immediately to continuously distribute keys and store keys in the key pool.

[0026] Step 1.2: Initial configuration of protection interval: The default setting is in the middle frequency band between the highest frequency slot occupied by classical signals and the lowest frequency slot occupied by quantum signals, forming a fixed-bandwidth isolation zone between classical and quantum signals. The guard interval is a dynamically movable vacant frequency slot area, which only serves as an isolation zone to reduce the interference of noise generated during classical optical signal transmission on quantum signals. It is not allocated to any service use, and its position is adjusted in real time by the SDN controller according to the key pool status and service load.

[0027] Step 1.3: Key Pool Initialization: A key pool is constructed for each node pair at both ends of the link, with all key pools having the same initial key quantity and capacity limit. Key pool management employs a first-in, first-out (FIFO) mechanism. If the key quantity in a key pool reaches its capacity limit, older, unused keys are discarded, while newly generated keys are continuously injected to ensure the security of the keys within the pool. A dual threshold is set for the key pool: when the key quantity drops to the warning threshold, it serves as one of the conditions for triggering a protection interval shift, allowing for adjustment during the shift; when the key quantity continues to drop to the emergency threshold, it directly triggers a protection interval shift.

[0028] Step 2, the business routing path calculation process, is implemented based on the business routing path calculation module and includes: The SDN controller receives service requests from the entire network in real time, distinguishes between classic and security service types, and employs differentiated routing calculation strategies. It then combines these with frequency slot resource status to select the optimal path. The specific steps are as follows: Step 2.1: Business Requirements Breakdown: When a service arrives, the SDN controller obtains the service type from the service layer through the northbound interface and breaks down the service requirements. One type is classic services, which refer to data services in ordinary optical networks that do not require key encryption. The controller needs to know key parameters such as source and destination nodes and bandwidth requirements. The other type is secure services, which refer to data services that require key encryption. These services need to occupy two classic channels simultaneously: one for the key path to apply for the end-to-end global key, and the other for the classic path to transmit encrypted data. The controller needs to know key parameters such as source and destination nodes, bandwidth requirements, and key quantity requirements.

[0029] Step 2.2: Classic Service Route Calculation: The k-Shortest Paths (KSP) algorithm is invoked to calculate multiple candidate paths using hop count as weights, while simultaneously obtaining the frequency slot occupancy status of each link on each path. Based on the frequency slot consistency principle, the path that meets the service bandwidth requirements and has the lowest consecutive idle frequency slot frequency is prioritized, and routing and frequency slot allocation commands are issued via the southbound interface. If frequency slot allocation fails, the process proceeds to step three, the frequency slot allocation optimization process.

[0030] Step 2.3: Calculation of secure service routes: The KSP algorithm is invoked to calculate multiple candidate paths, weighted by hop count. The path with the strongest key supply capacity is selected as the key path, provided the key quantity requirement is met without frequency slot requirements. If the minimum remaining key pool amount on all candidate paths falls below the emergency threshold, or if there are no available consecutive frequency slots, the security service will be directly blocked. Classic paths only require frequency slot consistency, and their selection method is the same as in step 2. When both paths meet the service requirements, key and frequency slot resources are allocated respectively, and routing begins.

[0031] Step 3, the protection interval adjustment process, is implemented based on the protection interval adjustment module and includes: The SDN controller dynamically adjusts the protection interval based on the remaining amount of the key pool and the generation and consumption rates to stabilize the continuous supply capacity of the key pool and reduce interruptions to classic services. The specific steps are as follows: Step 3.1: Pre-adjustment of protection interval: The SDN controller extracts keys from the key pool as needed based on key requests, updates key resources periodically, and monitors the key generation and consumption rates in real time. When the remaining key quantity in the key pool drops to the warning threshold and the key consumption rate exceeds the key generation rate for a period of time, the protection interval is moved to a lower frequency direction. If the protection interval will occupy the classic channel where service transmission is in progress, frequency slot allocation optimization will be triggered, and the process will jump to step 4.2.

[0032] Step 3.2: Guard Interval Movement: When the key quantity drops further to the emergency threshold, the protection interval will be moved directly. If there is a classic signal being transmitted on the low-frequency channel to which it will be moved, the signal will be cut off and the corresponding service will be blocked. When the key quantity rises to the warning threshold and the key generation rate exceeds the key consumption rate for a period of time, the protection interval of this link will be moved back to the initial state.

[0033] Step 4, the frequency slot allocation optimization process, is implemented based on the frequency slot allocation optimization module and includes: Frequency slot allocation optimization is a dynamic adjustment mechanism to address routing failures or insufficient key resources. It achieves efficient resource utilization through rerouting and guard interval shifting. The specific steps are as follows: Step 4.1: Route Selection Optimization: Among the alternative paths calculated by KSP, starting from the path with the fewest overlapping links, rerouting calculation is performed on the original path with overlapping links to find idle paths and frequency slots. If available frequency slots are available, the original path will be rerouted, and the coordinated frequency slots will be allocated to the current service. If the rerouting calculation fails, the current service will be blocked.

[0034] Step 4.2: Optimization of the protection interval shifting phase: If the guard interval shift condition is triggered, i.e., the available frequency slots for classical signals are reduced, the guard interval will shift to a lower frequency and the available frequency slots for quantum signals will be increased. The distance the guard interval shifts will be determined by the number of boundaries of that link segment. If the shifted guard interval conflicts with the frequency slots of classical services still in operation, a rerouting calculation will be performed for the classical service path. If rerouting is not possible, the service will be directly blocked.

[0035] Step 5, Resource Status Update Process, based on the resource status update module, includes: Once the transmission of classic or secure services is completed, the node corresponding to the service immediately reports the service termination information to the SDN controller. After receiving the information, the SDN controller issues a frequency slot release command to release all frequency slot resources occupied by the service and synchronously updates the idle status of frequency slot resources across the entire network and the remaining amount of key pools in each node.

[0036] The following section provides further explanation of this routing and spectrum allocation optimization method using specific application examples: like Figure 2 As shown, specifically in Figure 2 In Figure (a), each node is equipped with sufficient quantum and classical devices to meet the physical conditions for the implementation of the scheme. Figure 2 As shown in the left figure of Figure (c), quantum and classical transmissions on each link are carried out together in the C-band (1530-1565nm). The bandwidth of the smallest frequency slot unit is 25GHz, numbered 1-20 from low frequency to high frequency. The routing and spectrum allocation optimization method for quantum and classical coexistence is adopted for specific implementation, and the steps are as follows: Step 1: Resource Initialization Step 1.1: Fixed frequency slot resource configuration: Classical signal bandgap configuration: Bandgap numbers 1-4 are allocated to classical signals as fixed classical signal transmission channels; Quantum signal bandgap configuration: Bandgap numbers 17-20 are allocated to quantum signals as fixed quantum signal transmission channels, with an initial key rate of 2kbps for each link segment.

[0037] Step 1.2: Initial configuration of protection interval: The frequency gaps numbered 15-16 are allocated to the guard interval, and the high-frequency portion of the guard interval is allocated to the quantum signal to continuously perform quantum key distribution.

[0038] Step 1.3: Key Pool Initialization: In this embodiment, a symmetric key pool is configured for each pair of nodes, with an initial key quantity of 1000 and a maximum capacity of 10000. The global key update cycle is 10 seconds. A dual threshold is set for the key pool, including an early warning threshold. Emergency threshold 。

[0039] Step 2. Business routing path calculation: The SDN controller obtains the frequency slot occupancy of each link as Figure 2 shown in Figure (c) in the middle, and the key resources of each link are shown in Table 1.

[0040] Step 2.1: Business requirement breakdown: At time t1, a service arrives. The SDN controller reads the key requirement k = 10, determines it as a secure service, with the source and destination nodes being A and D respectively, and the bandwidth requirement being 25 GHz. Then, 1 frequency slot needs to be allocated to the classical path among them.

[0041] Step 2.2: Data transmission routing calculation: Call the KSP algorithm to calculate 3 alternative paths with the minimum number of hops: A-D (L5), A-B-D (L1-L4), and A-C-D (L2-L3). Among them, there is no idle frequency slot available for allocation for L5 corresponding to A-D, the lowest continuous frequency slot available for A-B-D is the 5th frequency slot, and the lowest continuous frequency slot available for A-C-D is the 1st frequency slot. Therefore, select L2-L3 as the data transmission path for this secure service.

[0042] Step 2.3: Key relay routing calculation: Among the 3 alternative paths, the remaining key amount of L5 corresponding to A-D is 100, the remaining key amount of L1 in A-B-D is 400, and the remaining key amount of L3 in A-C-D is 500. Therefore, select L2-L3 as the key relay path for this secure service.

[0043] The requirements of the service have been met, and the allocation of routing and key resources begins.

[0044] Table 1 shows the key resources of each link at time t1

[0045] 4.2.3 Protection interval adjustment As Figure 2 shown in Figure (b) in the middle, at time t2, the remaining key amount of L5 drops to the warning threshold of 50, and RSKR < RCON continues until t3. The pre-adjustment of the protection interval begins, and it is necessary to move the 15th and 16th frequency slots of the original protection interval of L5 to the 5th and 6th frequency slots. As Figure 2 shown in Figure (c) in the middle, the classical service (A-D) occupying the 5th and 6th frequency slots has not left yet. Therefore, it is necessary to perform re-routing calculation on it.

[0046] Step 4. Frequency slot allocation optimization: Step 4.1: Re-routing calculation: There are two alternative rerouting paths for the classic services in progress on L5: A - B - D (L1 - L4) and A - C - D (L2 - L3). The lowest consecutive idle frequency gaps on L1 - L4 are numbers 5 and 6, and the lowest consecutive idle frequency gaps on L2 - L3 are numbers 6 and 7. Therefore, the original A - D path is migrated to frequency gaps 5 and 6 on L1 - L4.

[0047] Step 4.2: Protection interval movement: Move frequency gaps 15 and 16 of the protection interval of L5 to frequency gaps 5 and 6. Allocate frequency gaps 7 - 20 to quantum signals for quantum key distribution to quickly replenish the key pool. At time t4, the remaining amount of L5 keys grows to 50, and RSKR < RCON continues until t5. Then, directly move the protection interval back to its position in the initialization phase, that is, frequency gaps 15 and 16.

[0048] Step Five: Resource status update: Service At the moment of leaving, the SDN controller issues an instruction to release frequency gap 1 on L2 - L3, and synchronously updates the remaining amount of keys in the key pools of each node, the key generation rate and consumption rate of each link, and the occupancy of frequency gaps.

[0049] As Figure 4 shown, this embodiment also provides a routing and spectrum allocation optimization system for coexistence of quantum and classic services, including: a routing selection module, which is used to distinguish the service types of received service requests, adopt a differential routing calculation strategy for different service types, and select the optimal path in combination with the status of frequency gap resources for service transmission according to the optimal path; a dynamic adjustment module, which is used to dynamically adjust the protection interval during service transmission according to the remaining amount, generation rate and consumption rate of the key pool; when the routing calculation fails or the remaining amount of the key pool is insufficient, achieve the allocation optimization of frequency gap resources through rerouting calculation or adjustment of the protection interval; a frequency gap release module, which is used to issue a frequency gap release instruction according to the service termination information reported by the service node after the service request completes transmission, so as to release all the frequency gap resources occupied by the current service according to the frequency gap release instruction, and update the idle status of frequency gap resources and the remaining amount of the key pool of each service node.

[0050] The present invention also provides a routing and spectrum allocation optimization device for coexistence of quantum and classic services, including: a memory for storing a computer program; a processor for implementing the steps of the routing and spectrum allocation optimization method for coexistence of quantum and classic services when executing the computer program.

[0051] When the processor executes the computer program, it implements the above-mentioned steps for optimizing routing and spectrum allocation in the coexistence of quantum and classical technologies. For example, it distinguishes the received service requests by service type, adopts differentiated routing calculation strategies for different service types, and selects the optimal path based on the frequency slot resource status so as to transmit services according to the optimal path. During service transmission, the protection interval is dynamically adjusted based on the remaining amount of the key pool, the generation rate, and the consumption rate. When the route calculation fails or the remaining amount of the key pool is insufficient, the allocation of frequency slot resources is optimized by re-route calculation or adjustment of the protection interval. After the service request is transmitted, a frequency slot release command is issued based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of the frequency slot resources and the remaining amount of the key pool of each service node.

[0052] Alternatively, when the processor executes the computer program, it implements the functions of each module in the above system, such as: a routing module, which distinguishes the received service requests by service type, adopts a differentiated routing calculation strategy for different service types, and selects the optimal path in combination with the frequency slot resource status, so as to transmit services according to the optimal path; The dynamic adjustment module is used to dynamically adjust the protection interval based on the remaining amount of the key pool, the generation rate, and the consumption rate during service transmission; when the route calculation fails or the remaining amount of the key pool is insufficient, the allocation of frequency slot resources is optimized by re-route calculation or adjusting the protection interval. The frequency slot release module is used to issue a frequency slot release command after the service request has been transmitted, based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of the frequency slot resources and the remaining amount of the key pool of each service node.

[0053] For example, the computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing preset functions. These instruction segments describe the execution process of the computer program in the quantum and classical coexistence routing and spectrum allocation optimization device. For example, the computer program can be divided into a routing selection module, a dynamic adjustment module, and a frequency slot release module; the specific functions of each module are as follows: The routing selection module is used to distinguish the received service requests by service type, adopt differentiated routing calculation strategies for different service types, and select the optimal path based on the frequency slot resource status, so as to transmit services according to the optimal path; The dynamic adjustment module is used to dynamically adjust the protection interval based on the remaining amount of the key pool, the generation rate, and the consumption rate during service transmission; when the route calculation fails or the remaining amount of the key pool is insufficient, the allocation of frequency slot resources is optimized by re-route calculation or adjusting the protection interval. The frequency slot release module is used to issue a frequency slot release command after the service request has been transmitted, based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of the frequency slot resources and the remaining amount of the key pool of each service node.

[0054] The quantum-classical coexistence routing and spectrum allocation optimization device can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. This device may include, but is not limited to, processors and memory. Those skilled in the art will understand that the above are examples of quantum-classical coexistence routing and spectrum allocation optimization devices and do not constitute a limitation on such devices. They may include more components than described above, or combine certain components, or use different components. For example, the quantum-classical coexistence routing and spectrum allocation optimization device may also include input / output devices, network access devices, buses, etc.

[0055] The processor referred to can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or any conventional processor. This processor is the control center for the quantum-classical coexistence routing and spectrum allocation optimization, connecting various parts of the entire quantum-classical coexistence routing and spectrum allocation optimization device through various interfaces and lines.

[0056] The memory can be used to store the computer program and / or modules. The processor implements various functions of the quantum and classical coexistence routing and spectrum allocation optimization device by running or executing the computer program and / or modules stored in the memory and calling the data stored in the memory.

[0057] The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function (such as sound playback, image playback, etc.). The data storage area may store data created based on the use of the mobile phone (such as audio data, phonebook, etc.). Furthermore, the memory may include high-speed random access memory and non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital cards (SD cards), flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0058] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the described method for optimizing routing and spectrum allocation in a quantum-classical coexistence framework.

[0059] If the module / unit of the quantum and classical coexistence routing and spectrum allocation optimization system is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0060] Based on this understanding, the present invention can implement all or part of the processes in the above-mentioned routing and spectrum allocation optimization method for quantum and classical coexistence, or it can be accomplished by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the above-mentioned routing and spectrum allocation optimization method for quantum and classical coexistence. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or a preset intermediate form, etc.

[0061] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0062] It should be noted that the content contained in the computer-readable storage medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0063] Therefore, this invention provides a routing and spectrum allocation optimization method that allows for the coexistence of quantum and classical approaches, which has the following advantages compared to existing optimization methods: This method achieves unified management and dynamic scheduling of frequency slots and key resources in coexisting networks, overcoming the problems of low key rates and high service blocking rates when CV-QKD and classical optical networks coexist. By monitoring the frequency slots and key resources of each link in real time through an SDN controller, resources can be allocated on demand when services arrive, achieving collaborative resource management. Combined with spectrum optimization and differentiated routing strategies, classical and security services can coexist efficiently in the same network. Dual threshold settings for the key pool further ensure the stability of key supply, reducing exhaustion or overflow, and the key pool is flexibly replenished by dynamically adjusting the protection interval. Furthermore, this invention comprehensively considers the remaining key quantity, idle frequency slots, and link topology during routing calculations, improving the success rate and resource utilization of both security and classical services. This method enhances the network's controllability, scalability, and security, providing reliable technical support for the large-scale collaborative deployment of quantum-classical optical networks.

[0064] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A routing and spectrum allocation optimization method for the coexistence of quantum and classical approaches, characterized in that, include: The received service requests are distinguished by service type, and a differentiated routing calculation strategy is adopted for different service types. The optimal path is selected in combination with the frequency slot resource status so as to transmit services according to the optimal path. During business transmission, the protection interval is dynamically adjusted based on the remaining amount of the key pool, the generation rate, and the consumption rate. When routing calculation fails or the key pool is insufficient, the allocation of frequency slot resources is optimized by re-routing or adjusting the protection interval. After the service request is transmitted, a frequency slot release command is issued based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of the frequency slot resources and the remaining amount of the key pool of each service node.

2. The routing and spectrum allocation optimization method for quantum and classical coexistence according to claim 1, characterized in that, Before classifying received service requests by service type, employing differentiated routing calculation strategies for different service types, and selecting the optimal path based on the frequency slot resource status to transmit services according to the optimal path, the process also includes initializing and configuring the network environment's frequency slot resources, guard interval, and key pool. The specific steps are as follows: The low-frequency band of the optical spectrum is divided into classical signal frequency slot regions, and the high-frequency band is divided into quantum signal frequency slot regions. Fixed frequency slots are reserved in both types of frequency slot regions for continuous signal transmission. A fixed-bandwidth guard interval is set in the intermediate frequency band between the highest frequency gap of the classical signal and the lowest frequency gap of the quantum signal. The guard interval is a dynamically movable vacant frequency gap area, and the position of the guard interval is adjusted in real time according to the key pool status and business load. A key pool is built for the nodes at both ends of the link, a unified initial key quantity and capacity limit are set, a first-in-first-out mechanism is used to manage the keys, and warning thresholds and emergency thresholds are configured for the key pool.

3. The routing and spectrum allocation optimization method for quantum and classical coexistence according to claim 1, characterized in that, The process of distinguishing received service requests by service type, employing differentiated routing calculation strategies for different service types, and selecting the optimal path based on frequency slot resource status to transmit services according to the optimal path includes: Receive service requests, break down the service requests, and distinguish the service types; wherein, the service types include classic services and security services; If the service type is classic service, then extract the source and destination nodes and bandwidth requirement parameters; If the service type is security service, extract the source and destination nodes, bandwidth requirements, and key quantity requirements. Security services also occupy two classic channels simultaneously: one classic channel is the key path used to apply for the end-to-end global key, and the other classic channel is the classic path used to transmit encrypted data. The k-shortest path algorithm combined with the frequency slot resource status is used to select the optimal path for classic services; the k-shortest path algorithm combined with the frequency slot resource status is also used to select the optimal path for security services; differentiated routing calculation strategies are adopted for classic services and security services. Service transmission is performed according to the selected optimal path.

4. The routing and spectrum allocation optimization method for quantum and classical coexistence according to claim 3, characterized in that, The method of using the k-shortest path algorithm combined with the frequency slot resource status to select the optimal path for classic services includes: The k-shortest path algorithm is called to calculate multiple candidate paths with hop count as weight. Based on the principle of frequency slot consistency, the path that meets the bandwidth requirements and has the lowest continuous idle frequency band is selected, and routing and frequency slot allocation instructions are issued. If the allocation fails, rerouting is performed or the protection interval is adjusted to optimize the allocation of frequency slot resources.

5. The routing and spectrum allocation optimization method for quantum and classical coexistence according to claim 3, characterized in that, The method of using the k-shortest path algorithm combined with the frequency slot resource status to select the optimal path for security services includes: The k-shortest path algorithm is called to calculate multiple candidate paths with hop count as weight. The path with the strongest key supply capability is selected as the key path. Based on the frequency slot consistency principle, the path that meets the bandwidth requirements and has the lowest continuous idle frequency slot is selected as the classic path. If both paths meet the requirements, resources are allocated; otherwise, the service is blocked.

6. The routing and spectrum allocation optimization method for quantum and classical coexistence according to claim 1, characterized in that, The method of dynamically adjusting the protection interval based on the remaining amount of the key pool, the generation rate, and the consumption rate during service transmission includes: If the remaining key quantity is detected to drop to the warning threshold and the key consumption rate exceeds the generation rate for a preset time, the protection interval will be moved to a lower frequency direction; if it occupies a classic channel that is currently transmitting services, rerouting calculation or adjustment of the protection interval will be performed to optimize the allocation of frequency slot resources. When the remaining key amount drops to the emergency threshold, the protection interval is moved directly. If it occupies the in-transmission classical channel, the signal is cut off and the service is blocked. When the remaining key amount rises back to the warning threshold and the generation rate exceeds the consumption rate for a preset time, the protection interval is reset to the initial state.

7. The routing and spectrum allocation optimization method for quantum and classical coexistence according to claim 1, characterized in that, When routing calculation fails or the key pool has insufficient remaining funds, the allocation optimization of frequency slot resources is achieved through re-routing calculation or adjustment of the guard interval, including: When the route calculation fails or the key pool is insufficient, the route calculation is restarted from the path with the fewest overlapping links in the alternative paths of the k-shortest path algorithm to find an idle path and frequency slot. If an available frequency slot exists, it is allocated to the current service; otherwise, the service is blocked. When a protection interval is moved, the distance the protection interval moves to a lower frequency is determined by the number of link boundaries. If it conflicts with the frequency slot of the classic service being transmitted, a rerouting calculation is performed. If the rerouting fails, the service is blocked.

8. A routing and spectrum allocation optimization system that allows for the coexistence of quantum and classical technologies, characterized in that... include: The routing module is used to distinguish the received service requests by service type, adopt differentiated routing calculation strategies for different service types, and select the optimal path in combination with the frequency slot resource status so as to transmit services according to the optimal path. The dynamic adjustment module is used to dynamically adjust the protection interval based on the remaining amount of the key pool, the generation rate, and the consumption rate during service transmission. When routing calculation fails or the key pool is insufficient, the allocation of frequency slot resources is optimized by re-routing or adjusting the protection interval. The frequency slot release module is used to issue a frequency slot release command after the service request has been transmitted, based on the service termination information reported by the service node. This command releases all frequency slot resources currently occupied by the service and updates the idle status of the frequency slot resources and the remaining amount of the key pool of each service node.

9. A routing and spectrum allocation optimization device for the coexistence of quantum and classical technologies, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the routing and spectrum allocation optimization method for quantum and classical coexistence as described in any one of claims 1-7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it is used to implement the steps of the routing and spectrum allocation optimization method for quantum and classical coexistence as described in any one of claims 1-7.

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