WO2023108715A1 - Dedicated protection spectrum allocation method and system for space-division multiplexing optical network of data center - Google Patents

Abstract

The present invention relates to a dedicated protection spectrum allocation method and system for a space-division multiplexing optical network of a data center. In the method in the present invention, firstly, a working path and a dedicated protection path are established for each connection request; secondly, idle spectrum availability values of all fiber cores are calculated according to a spectrum usage condition on each optical fiber link, and the idle spectrum availability values are arranged in descending order, so as to sequentially select the fiber cores; then, under the constraints of spectrum continuity and consistency, an available spectrum block is selected, and a crosstalk value of the spectrum block on each link is calculated; and subsequently, whether the crosstalk value on each link satisfies a crosstalk threshold limitation is determined, and if so, the spectrum block is retained, and spectrum allocation is performed. In this way, the problems of routing calculation, fiber core selection and spectrum allocation based on crosstalk awareness are solved, the spectrum resource efficiency of a space-division multiplexing optical network is improved, and the crosstalk value of each optical fiber link is reduced, such that spectrum resources occupied by a working path and a dedicated protection path, which are established for each connection request, and the crosstalk are optimized.

Description

Method and system for allocating special protection spectrum for space division multiplexing optical network in data center technical field

The invention relates to the technical field of communication networks, in particular to a method and system for allocating dedicated protection spectrums for space division multiplexing optical networks in data centers.

Background technique

Since the bandwidth requirements provided by the traditional wavelength division multiplexing optical network cannot meet the requirements for the rapid growth of optical network bandwidth in recent years, nor can it guarantee the high resource efficiency of the network, and the elastic optical network can flexibly segment and allocate the network according to business needs. Spectrum resources avoid spectrum waste and improve the utilization of spectrum resources. Therefore, elastic optical network has become a research hotspot at present.

The traditional elastic optical network based on single-mode single-core optical fiber is facing the challenge of reaching the limit of physical capacity. In order to solve this problem, the space division multiplexing technology represented by multi-core optical fiber transforms the original single-core optical fiber into multi-fiber Theoretically, the capacity of the optical fiber can be expanded to a multiple of the number of cores, which greatly improves the transmission capacity of the optical fiber. However, in multi-core optical fiber, when the optical signal is transmitted between different cores, power leakage will occur, which will cause crosstalk between different cores and affect the end-to-end optical signal transmission quality, thus limiting the use of multi-core optical fiber. Transmission range and deployment scale. In particular, when services allocate network spectrum resources in a multi-core elastic optical network, if the spectrum slots with the same number in adjacent cores are occupied at the same time, large inter-core crosstalk will occur, and the crosstalk value exceeds a certain The range will interfere with the normal transmission of the optical signal in the optical fiber and affect the transmission quality of the optical signal. Therefore, in the space division multiplexing optical network based on multi-core optical fiber, it is necessary to fully consider the crosstalk between the cores, and control the crosstalk value below the maximum tolerable crosstalk value threshold.

The problem of routing and spectrum allocation is the core problem of elastic optical network, and this problem is extended to the problem of routing, fiber core and spectrum allocation in space division multiplexing optical network. In the single-core elastic optical network, the service uses the first hit or random hit method to find the spectrum resources required for the connection request in the selected working path. The selected spectrum resources only need to meet the two requirements of spectrum continuity and spectrum consistency. This is due to the fact that there is no crosstalk problem between adjacent fiber cores in the traditional elastic optical network, and it is impossible to investigate the influence of the spectral overlap degree of adjacent fiber cores on the crosstalk. However, in the space-division multiplexing optical network, since the space-division multiplexing optical network carries several times more business traffic than the traditional elastic optical network, it is necessary to effectively protect network data services and prevent service losses caused by network failures. Therefore, in the space division multiplexing optical network, the problem of network survivability needs to be considered to ensure the rapid recovery capability of data services and ensure the reliability of data service transmission. Dedicated path protection is one of the most commonly used and most effective protection methods. Usually, the dedicated path protection establishes a protection path with disjoint links for each working path after the working paths are established, and the spectrum resources on the protection paths cannot be shared, but are used as dedicated backup spectrum resources.

Therefore, solving the problems of working path and protection path calculation, fiber core selection and spectrum resource allocation in the space division multiplexing elastic optical network of the data center network is a crucial issue.

Contents of the invention

For this reason, the technical problem to be solved by the present invention is to overcome the problems existing in the prior art, and propose a method and system for allocating special protection spectrum for the space division multiplexing optical network of the data center, which solves the problem of routing calculation based on crosstalk perception, fiber core The problem of selection and spectrum allocation improves the efficiency of spectrum resources in space-division multiplexing optical networks, reduces the crosstalk value of each optical fiber link, and makes the spectrum resources occupied by the working path and dedicated protection path occupied by each connection request and Crosstalk is optimized.

In order to solve the above-mentioned technical problems, the present invention provides a method for allocating dedicated protection spectrum for a space division multiplexing optical network in a data center, comprising the following steps:

S1: Initialize the space division multiplexing elastic optical network for the data center network;

S2: Generate a connection request, wherein the connection request includes a data center source node and a data center destination node;

S3: Calculate the route of the connection request according to the source node of the data center and the destination node of the data center, and calculate a plurality of working paths from the source node of the data center to the destination node of the data center for the connection request and disjoint paths with the working paths Dedicated protection path, if the path is successfully built, the path with the shortest distance is selected in descending order as the working path and the dedicated protection path, if the path fails to be established, the connection request is judged as blocked;

S4: Calculate the idle spectrum availability value of each fiber core on the working path, and select the fiber core with the largest idle spectrum availability value for transmission;

S5: Find an available spectrum block that satisfies the spectrum consistency and continuity constraints in the link selected from the working path and the fiber core used for transmission, and if an available spectrum block that meets the requirements can be found, calculate the available spectrum block By the crosstalk value of the fiber core, if the available spectrum block that meets the requirements cannot be found, return to S4, and select the next fiber core in descending order according to the free spectrum availability value, until all the fiber cores are traversed, and all the fiber cores are When there is no available spectrum block that meets the requirements, the connection request is judged as blocked;

S6: Judging whether the crosstalk value of the available spectrum block is greater than the maximum allowable crosstalk value of the link, if the judgment result is no, keep the available spectrum block, if the judgment result is yes, delete the available spectrum block, and continue Search until all cores are traversed, and when there is no available spectrum block that meets the crosstalk requirements in all cores, the connection request is judged as blocked;

S7: Calculate the crosstalk values of the available spectrum blocks that meet the crosstalk requirements on all links of the working path in the fiber core used for transmission, and judge whether the crosstalk values on each link meet the threshold requirements. If the judgment result is yes, Then establish a connection request, if the judgment result is no, then the connection request is judged as blocked;

S8: Repeat S4-S7 to complete the inter-core crosstalk calculation and frequency spectrum allocation on the dedicated protection path.

In one embodiment of the present invention, in S1, the data center network-oriented space division multiplexing elastic optical network is initialized, including:

Initialize the topology information, link connection status, number of data centers, number of fiber links, number of cores of each fiber, and number of spectrum slots of each fiber link in the space division multiplexing elastic optical network.

In an embodiment of the present invention, in S4, calculating the free spectrum availability value of each fiber core on the working path includes:

The idle spectrum availability value S _i of each core i on the working path is calculated according to the following formula:

Among them, |L| indicates the number of links on the current working path, |F| indicates the number of spectrum slots of each fiber core, S _k,i indicates that the number of kth free spectrum slots on core i is greater than or equal to FS The spectrum block of , FS represents the number of spectrum slots required by the connection request.

In one embodiment of the present invention, in S5, calculating the crosstalk value of the fiber core that the available spectrum block is subjected to includes:

For available spectrum blocks

According to the following formula, the spectrum slot number j in the available spectrum block is affected by the crosstalk of adjacent cores

Among them, α and β are adjustable factors, n represents the core set adjacent to _ci ,

is a binary variable, taking 1 means that the spectral slot numbered j in the core r adjacent to c _i on the link l has been occupied, and taking 0 means it is not occupied;

Calculate the available spectrum block according to the following formula

crosstalk value

Among them, n is the number of cores adjacent to the selected core c _i , L is the length of the current link l,

is the average growth value of inter-core crosstalk per unit fiber length, k, r, β, and Λ are fiber parameters, which represent the coupling coefficient, bending radius, propagation coefficient and fiber-core spacing, respectively.

In an embodiment of the present invention, S9 is further included, evaluating the performance parameters of the network after all the connection requests have completed the inter-core crosstalk calculation and frequency spectrum allocation on the working path and the dedicated protection path.

In addition, the present invention also provides a data center space division multiplexing optical network dedicated protection spectrum allocation system, including:

A network initialization module, the network initialization module is used to initialize the space division multiplexing elastic optical network oriented to the data center network;

A connection request generation module, the connection request generation module is used to generate a connection request, wherein the connection request includes a data center source node and a data center target node;

A route calculation module, the route calculation module is used to calculate the route of the connection request according to the source node of the data center and the destination node of the data center, and calculate a plurality of routes from the source node of the data center to the destination node of the data center for the connection request For the working path and the dedicated protection path that does not intersect with the working path, if the path is successfully established, the path with the shortest distance is selected in descending order as the working path and the dedicated protection path. If the path fails to be established, the connection request is judged as blocked;

An idle spectrum availability selection module, the idle spectrum availability selection module is used to calculate the idle spectrum availability value of each fiber core on the working path, and select the fiber core with the largest idle spectrum availability value for transmission;

A crosstalk constraint module, the crosstalk constraint module is used to search for an available spectrum block that meets the spectrum consistency and continuity constraints in the link selected from the working path and the fiber core used for transmission, if it can be found to meet the requirements available spectrum block, then calculate the crosstalk value of the available spectrum block by the fiber core, and judge whether the crosstalk value of the available spectrum block is greater than the maximum allowable crosstalk value of the link, if the judgment result is no, then reserve the available spectrum block, if the judgment result is yes, delete the available spectrum block, and continue to search until all the cores have been traversed, and when there is no available spectrum block that meets the crosstalk requirements in all the cores, the connection request is judged as blocked ; If the available spectrum blocks that meet the requirements cannot be found, return to S4, and select the next fiber core in descending order according to the free spectrum availability value, until all fiber cores have been traversed, and there is no available spectrum that meets the requirements in all fiber cores block, the connection request is judged as blocked;

Spectrum allocation module, the spectrum allocation module is used to calculate the crosstalk value on all links of the working path of the available spectrum block meeting the crosstalk requirement in the fiber core used for transmission, and judge whether the crosstalk value on each link satisfies Threshold requirements, if the judgment result is yes, then establish a connection request, if the judgment result is no, then the connection request is judged to be blocked; repeat the process of crosstalk calculation and spectrum allocation on the working path, and complete the crosstalk calculation between cores on the dedicated protection path and spectrum allocation.

In one embodiment of the present invention, the free spectrum available selection module includes:

An idle spectrum availability calculation unit, the idle spectrum availability calculation unit is used to calculate the idle spectrum availability value S _i of each fiber core i on the working path according to the following formula:

Among them, |L| indicates the number of links on the current working path, |F| indicates the number of spectrum slots of each fiber core, S _k,i indicates that the number of kth free spectrum slots on core i is greater than or equal to FS The spectrum block of , FS represents the number of spectrum slots required by the connection request.

In one embodiment of the present invention, the free spectrum available selection module includes:

A fiber core selection unit, the fiber core selection unit is configured to arrange the fiber cores in descending order according to the idle spectrum availability value, and select the fiber core with the largest idle spectrum availability value for transmission.

In one embodiment of the present invention, the crosstalk constraint module includes:

A crosstalk calculation module, the crosstalk calculation module is used to calculate the crosstalk value of the available spectrum block subjected to the fiber core, including:

For available spectrum blocks

According to the following formula, the spectrum slot number j in the available spectrum block is affected by the crosstalk of adjacent cores

Among them, α and β are adjustable factors, n represents the core set adjacent to _ci ,

is a binary variable, taking 1 means that the spectral slot numbered j in the core r adjacent to c _i on the link l has been occupied, and taking 0 means it is not occupied;

Calculate the available spectrum block according to the following formula

crosstalk value

Among them, n is the number of cores adjacent to the selected core c _i , L is the length of the current link l,

is the average growth value of inter-core crosstalk per unit fiber length, k, r, β, and Λ are fiber parameters, which represent the coupling coefficient, bending radius, propagation coefficient, and fiber-core spacing, respectively.

In one embodiment of the present invention, also include:

A network performance evaluation module, the network performance evaluation module is used to evaluate the performance parameters of the network after all the connection requests have completed the inter-core crosstalk calculation and frequency spectrum allocation on the working path and the dedicated protection path.

The above technical solution of the present invention has the following advantages compared with the prior art:

The invention solves the problems of routing calculation, fiber core selection and spectrum allocation based on crosstalk perception, improves the spectrum resource efficiency of space division multiplexing optical network, reduces the crosstalk value of each optical fiber link, and makes each connection request The spectrum resource and crosstalk occupied by the established working path and dedicated protection path are optimized.

Description of drawings

In order to make the content of the present invention more clearly understood, the present invention will be further described in detail below according to the specific embodiments of the present invention and in conjunction with the accompanying drawings.

FIG. 1 is a schematic flowchart of a method for allocating dedicated protection spectrum for a space-division multiplexing optical network in a data center according to the present invention.

Fig. 2 is a schematic diagram of the hardware structure of the space division multiplexing optical network dedicated protection spectrum allocation system of the data center of the present invention.

Fig. 3 is the topology diagram of the NSFNET network of the present invention.

Fig. 4 is a schematic diagram of the groove auxiliary structure of the seven-core optical fiber of the present invention.

Fig. 5 is a schematic diagram of the numbering and arrangement of the seven-core optical fiber of the present invention.

Fig. 6 is a schematic diagram of the spectrum occupancy state on the working path of the present invention.

Wherein, the reference numerals are described as follows: 10. Network initialization module; 20. Connection request generation module; 30. Routing calculation module; 40. Free spectrum available selection module; 50. Crosstalk constraint module; 60. Spectrum allocation module; 70. Network performance evaluation module; 80. Network status monitoring module; 90. Judgment early warning module.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the examples given are not intended to limit the present invention.

Please refer to FIG. 1, the present embodiment provides a method for allocating dedicated protection spectrum for a space division multiplexing optical network in a data center, including the following steps:

S1: Initialize the space division multiplexing elastic optical network for the data center network;

S2: Generate a connection request, wherein the connection request includes a data center source node and a data center destination node;

S3: Calculate the route of the connection request according to the source node of the data center and the destination node of the data center, and calculate a plurality of working paths from the source node of the data center to the destination node of the data center for the connection request and disjoint paths with the working paths Dedicated protection path, if the path is successfully built, the path with the shortest distance is selected in descending order as the working path and the dedicated protection path, if the path fails to be established, the connection request is judged as blocked;

S4: Calculate the idle spectrum availability value of each fiber core on the working path, and select the fiber core with the largest idle spectrum availability value for transmission;

S5: Find an available spectrum block that satisfies the spectrum consistency and continuity constraints in the link selected from the working path and the fiber core used for transmission, and if an available spectrum block that meets the requirements can be found, calculate the available spectrum block By the crosstalk value of the fiber core, if the available spectrum block that meets the requirements cannot be found, return to S4, and select the next fiber core in descending order according to the free spectrum availability value, until all the fiber cores are traversed, and all the fiber cores are When there is no available spectrum block that meets the requirements, the connection request is judged as blocked;

S6: Judging whether the crosstalk value of the available spectrum block is greater than the maximum allowable crosstalk value of the link, if the judgment result is no, keep the available spectrum block, if the judgment result is yes, delete the available spectrum block, and continue Search until all cores are traversed, and when there is no available spectrum block that meets the crosstalk requirements in all cores, the connection request is judged as blocked;

S7: Calculate the crosstalk values of the available spectrum blocks that meet the crosstalk requirements on all links of the working path in the fiber core used for transmission, and judge whether the crosstalk values on each link meet the threshold requirements. If the judgment result is yes, Then establish a connection request, if the judgment result is no, then the connection request is judged as blocked;

S8: Repeat S4-S7 to complete the inter-core crosstalk calculation and frequency spectrum allocation on the dedicated protection path.

Among them, in S1, the data center network-oriented space division multiplexing elastic optical network is initialized, including:

Initialize the topology information, link connection status, number of data centers, number of fiber links, number of cores of each fiber, and number of spectrum slots of each fiber link in the space division multiplexing elastic optical network.

In a preferred solution, the space division multiplexing elastic optical network is represented by G(E, V, C, F), where E={E ₁ , E ₂ ,...,E _|E| }, V={V ₁ ,V ₂ ,…,V _|V| }, C＝{C ₁ ,C ₂ ,…,C |C _| }, F＝{F ₁ ,F ₂ ,…,F _|F| } respectively represent the data center The collection of optical fiber links, data centers, fiber cores and available spectrum in the space-division multiplexing elastic optical network, |E|, |V|, |C|, |F| represent the space-division multiplexing elastic optical network The number of optical fiber links, the number of data centers, the number of fiber cores and the number of spectral slots of each fiber core, (V _i , V _j )∈E, where V _i , V _j ∈V, means that from the data center V Fiber link from _i to data center _Vj .

Wherein, in S4, the free spectrum availability value of each fiber core on the working path is calculated, including:

Calculate the idle spectrum availability value S _i of each core i on the working path according to formula (1):

Among them, |L| indicates the number of links on the current working path, |F| indicates the number of spectrum slots of each fiber core, S _k,i indicates that the number of kth free spectrum slots on core i is greater than or equal to FS The spectrum block of , FS represents the number of spectrum slots required by the connection request.

After the free spectrum availability value of each fiber core is calculated and obtained, the free spectrum availability value is arranged in descending order, and the fiber core is selected for transmission in descending order.

Wherein, in S5, the calculation of the crosstalk value of the available spectrum block by the fiber core includes:

S5.1: For available spectrum blocks

According to formula (2), calculate the spectrum slot numbered j in the available spectrum block by the crosstalk influence value of the adjacent fiber core

Among them, α and β are adjustable factors, n represents the core set adjacent to _ci ,

is a binary variable, taking 1 means that the spectral slot numbered j in the core r adjacent to c _i on the link l has been occupied, and taking 0 means it is not occupied;

S5.2: Calculate available spectrum blocks according to formula (3)

crosstalk value

Among them, n is the number of cores adjacent to the selected core c _i , L is the length of the current link l,

is the average growth value of inter-core crosstalk per unit fiber length, k, r, β, and Λ are fiber parameters, which represent the coupling coefficient, bending radius, propagation coefficient, and fiber-core spacing, respectively.

The above-mentioned available spectrum blocks are obtained in the calculation

crosstalk value

after that will

The maximum allowable crosstalk value with the current link

compare, if

reserved spectrum block

like

delete spectrum block

Continue to search, if the spectrum block that meets the crosstalk requirements cannot be found after traversing all the cores, the connection request is judged as blocked.

It also includes S9, after all the connection requests have completed the inter-core crosstalk calculation and frequency spectrum allocation on the working path and the dedicated protection path, evaluating the performance parameters of the network.

Please refer to FIG. 2, the present embodiment also provides a data center space division multiplexing optical network dedicated protection spectrum allocation system, including:

A network initialization module 10, the network initialization module 10 is used to initialize the space division multiplexing elastic optical network oriented to the data center network;

A connection request generating module 20, configured to generate a connection request, wherein the connection request includes a data center source node and a data center destination node;

A route calculation module 30, the route calculation module 30 is used to calculate the route of the connection request according to the data center source node and the data center destination node, and calculate a plurality of routes from the data center source node to the data center destination node for the connection request. The working path of the node and the dedicated protection path that does not intersect with the working path. If the path is successfully established, the path with the shortest distance is selected in descending order as the working path and the dedicated protection path. If the path fails to be established, the connection request is judged as blocked;

An idle spectrum availability selection module 40, the idle spectrum availability selection module 40 is used to calculate the idle spectrum availability value of each fiber core on the working path, and select the fiber core with the largest idle spectrum availability value for transmission;

A crosstalk constraint module 50, the crosstalk constraint module 50 is used to search for an available spectrum block that satisfies the spectrum consistency and continuity constraints in the link selected from the working path and the fiber core used for transmission, if it can be found If the available spectrum block meets the requirements, then calculate the crosstalk value of the available spectrum block by the fiber core, and judge whether the crosstalk value of the available spectrum block is greater than the maximum allowable crosstalk value of the link, if the judgment result is no, then keep the available spectrum block, if the judgment result is yes, then delete the available spectrum block, and continue to search until all fiber cores have been traversed, and when there is no available spectrum block that meets the crosstalk requirements in all fiber cores, the connection request is judged If the available spectrum block that meets the requirements cannot be found, return to S4, and select the next fiber core in descending order of the free spectrum availability value until all fiber cores have been traversed, and there is no satisfactory block in all fiber cores. When a spectrum block is available, the connection request is judged as blocked;

Spectrum allocation module 60, the spectrum allocation module 60 is used to calculate the crosstalk value on all links of the working path in the fiber core for transmission of the available spectrum block that meets the crosstalk requirement, and judge whether the crosstalk value on each link All meet the threshold requirements. If the judgment result is yes, the connection request will be established. If the judgment result is no, the connection request will be judged as blocking; repeat the process of crosstalk calculation and spectrum allocation on the working path to complete the inter-core protection on the dedicated protection path. Crosstalk calculation and spectrum allocation.

Wherein, the free spectrum available selection module 40 includes:

An idle spectrum availability calculation unit, the idle spectrum availability calculation unit is used to calculate the idle spectrum availability value S _i of each fiber core i on the working path according to formula (1):

Among them, |L| indicates the number of links on the current working path, |F| indicates the number of spectrum slots of each fiber core, S _k,i indicates that the number of kth free spectrum slots on core i is greater than or equal to FS The spectrum block of , FS represents the number of spectrum slots required by the connection request.

Wherein, the free spectrum available selection module 40 includes:

A fiber core selection unit, the fiber core selection unit is configured to arrange the fiber cores in descending order according to the idle spectrum availability value, and select the fiber core with the largest idle spectrum availability value for transmission.

Wherein, the crosstalk constraint module 50 includes:

A crosstalk calculation module, the crosstalk calculation module is used to calculate the crosstalk value of the available spectrum block subjected to the fiber core, including:

For available spectrum blocks

According to formula (2), calculate the spectrum slot numbered j in the available spectrum block by the crosstalk influence value of the adjacent fiber core

Among them, α and β are adjustable factors, n represents the core set adjacent to _ci ,

is a binary variable, taking 1 means that the spectral slot numbered j in the core r adjacent to c _i on the link l has been occupied, and taking 0 means it is not occupied;

Calculate available spectrum blocks according to formula (3)

crosstalk value

Among them, n is the number of cores adjacent to the selected core c _i , L is the length of the current link l,

is the average growth value of inter-core crosstalk per unit fiber length, k, r, β, and Λ are fiber parameters, which represent the coupling coefficient, bending radius, propagation coefficient and fiber-core spacing, respectively.

The network performance evaluation module 70 is also included, and the network performance evaluation module is used to evaluate the performance parameters of the network after all the connection requests have completed the inter-core crosstalk calculation and spectrum allocation on the working path and the dedicated protection path.

Also includes a network status monitoring module 80, the network status monitoring module 80 mainly completes the data center space division multiplexing elastic optical network parameter initialization, connection request generation, route calculation, idle spectrum availability calculation, fiber core selection, crosstalk Monitoring functions for computing, spectrum resource allocation, and network performance evaluation.

Also includes a judgment early warning module 90, the judgment early warning module 90 is used to execute the coordination function between each module, and whether each module establishes a successful judgment and early warning function, and completes the routing in the space division multiplexing elastic optical network of the data center The purpose of fiber core and spectrum allocation is to improve the performance of the network and reduce the value of crosstalk.

The NSFNET network topology shown in Figure 3 has a total of 14 nodes and 21 bidirectional links. The value on the optical fiber link indicates the length of the link in km. The spectrum bandwidth of each link is set to 200GHz. The bandwidth of the slot is 12.5 GHz, that is, there are 16 spectrum slots in each fiber core, and each fiber link uses a seven-core fiber, and the seven-core fiber adopts the groove auxiliary structure shown in Figure 4. The values are respectively set as: k=3.16×10 ^-5 , r=55(mm), β=4×10 ⁶ , Λ=45(μm), then

Assume that the current connection request arriving at the network is CR ₁ (2,11), K=3, according to the K shortest path algorithm, the working path is (2,5,12,11), and according to previous research, set each link on this path The maximum allowable crosstalk value of the road is

The numbering and arrangement of the seven-core optical fibers are shown in Figure 5. Assuming that when CR ₁ (2,11,2) arrives, the spectrum occupancy state in the fiber core is shown in Fig. 6 , wherein gray indicates that the spectrum slot is already occupied. According to (1), according to the spectrum continuity, the optional spectrum blocks in the core c ₁ on the link l ₁ are SS _1,1 , SS _2,1 and SS _3,1 , and the core c on the link l ₂ The optional spectrum blocks in ₁ are SS _1,1 and SS _2,1 , and the optional spectrum blocks in core c ₁ on link l ₃ are SS _1,1 , SS _2,1 and SS _3,1 . Therefore, the idle spectrum availability value of fiber core c ₁ is S ₁ =8, and by analogy, the idle spectrum availability value of fiber core c ₂ is S ₂ =5, and the idle spectrum availability value of fiber core c _{3 is} is S ₃ =7, the idle spectrum availability value of fiber core c ₄ is S ₄ =6, the idle spectrum availability value of fiber core c ₅ is S ₅ =4, and the idle spectrum availability value of fiber core c ₆ is S ₆ =6, the idle spectrum availability value of the core c ₇ is S ₇ =6. Therefore, the fiber core c ₁ is preferred for transmission. Suppose τ ₀ =0.5, τ ₁ =3, then on the link l ₁ , the length of the optical fiber link is 1300 (km), according to the spectrum consistency constraint and the first hit method, first calculate the spectrum blocks numbered 3 and 4

Influenced by crosstalk from adjacent cores on link l ₁

and inter-core crosstalk

because

So will

delete. Turn to calculate the spectral blocks numbered 4 and 5

On the link l ₁ , it is affected by the crosstalk value of the adjacent core and the crosstalk value between the cores: because

so keep

On the link l ₂ , the link length is 1400(km),

Satisfies crosstalk threshold constraints, reserved. On the link l ₃ , the link length is 300(km),

Satisfy the crosstalk threshold constraint, and finally select the free spectrum blocks numbered 4 and 5

Next, establish dedicated protection paths (2, 1, 7, 9, 11) for CR ₁ that have no overlapping links with the working path, and repeat the above calculation and selection process according to the spectrum occupancy status of each link.

The establishment process of other connection requests is similar to the above.

The present invention first establishes a working path and a dedicated protection path for each connection request to ensure the survivability of the space-division multiplexing optical network in the data center; secondly, in order to reduce the generation of spectrum fragments, calculate The free spectrum availability values of all cores are arranged in descending order, and the cores are selected in turn; then, under the constraints of spectrum continuity and consistency, select an available spectrum block and calculate the crosstalk value of the spectrum block on each link; Then, judge whether the crosstalk value on each link satisfies the limit of the crosstalk threshold, if so, reserve the spectrum block, and carry out spectrum allocation, thus solving the problem of routing calculation, fiber core selection and spectrum allocation based on crosstalk perception , improve the spectrum resource efficiency of the space division multiplexing optical network, reduce the crosstalk value of each optical fiber link, and optimize the spectrum resources and crosstalk occupied by the working path and the dedicated protection path established by each connection request.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

Apparently, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in various forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (10)

1. A data center space division multiplexing optical network dedicated protection spectrum allocation method, characterized in that it comprises the following steps:

   S1: Initialize the space division multiplexing elastic optical network for the data center network;

   S2: Generate a connection request, wherein the connection request includes a data center source node and a data center destination node;

   S3: Calculate the route of the connection request according to the source node of the data center and the destination node of the data center, and calculate a plurality of working paths from the source node of the data center to the destination node of the data center for the connection request and disjoint paths with the working paths Dedicated protection path, if the path is successfully built, the path with the shortest distance is selected in descending order as the working path and the dedicated protection path, if the path fails to be established, the connection request is judged as blocked;

   S4: Calculate the idle spectrum availability value of each fiber core on the working path, and select the fiber core with the largest idle spectrum availability value for transmission;

   S5: Find an available spectrum block that satisfies the spectrum consistency and continuity constraints in the link selected from the working path and the fiber core used for transmission, and if an available spectrum block that meets the requirements can be found, calculate the available spectrum block By the crosstalk value of the fiber core, if the available spectrum block that meets the requirements cannot be found, return to S4, and select the next fiber core in descending order according to the free spectrum availability value, until all the fiber cores are traversed, and all the fiber cores are When there is no available spectrum block that meets the requirements, the connection request is judged as blocked;

   S6: Judging whether the crosstalk value of the available spectrum block is greater than the maximum allowable crosstalk value of the link, if the judgment result is no, keep the available spectrum block, if the judgment result is yes, delete the available spectrum block, and continue Search until all cores are traversed, and when there is no available spectrum block that meets the crosstalk requirements in all cores, the connection request is judged as blocked;

   S7: Calculate the crosstalk values of the available spectrum blocks that meet the crosstalk requirements on all links of the working path in the fiber core used for transmission, and judge whether the crosstalk values on each link meet the threshold requirements. If the judgment result is yes, Then establish a connection request, if the judgment result is no, then the connection request is judged as blocked;

   S8: Repeat S4-S7 to complete the inter-core crosstalk calculation and frequency spectrum allocation on the dedicated protection path.
2. The method for allocating protection spectrum dedicated to the space division multiplexing optical network of the data center according to claim 1, wherein in S1, initializing the space division multiplexing elastic optical network oriented to the data center network includes:

   Initialize the topology information, link connection status, number of data centers, number of fiber links, number of cores of each fiber, and number of spectrum slots of each fiber link in the space division multiplexing elastic optical network.
3. The dedicated protection spectrum allocation method for the space division multiplexing optical network of the data center according to claim 1, wherein, in S4, calculating the idle spectrum availability value of each fiber core on the working path includes:

   The idle spectrum availability value S _i of each core i on the working path is calculated according to the following formula:

   

   Among them, |L| indicates the number of links on the current working path, |F| indicates the number of spectrum slots of each fiber core, S _k,i indicates that the number of kth free spectrum slots on core i is greater than or equal to FS The spectrum block of , FS represents the number of spectrum slots required by the connection request.
4. The space division multiplexing optical network dedicated protection spectrum allocation method of the data center according to claim 1, wherein, in S5, calculating the crosstalk value of the fiber core for the available spectrum block includes:

   For available spectrum blocks

   

   According to the following formula, the spectrum slot number j in the available spectrum block is affected by the crosstalk of adjacent cores

   

   

   Among them, α and β are adjustable factors, n represents the core set adjacent to _ci ,

   

   is a binary variable, taking 1 means that the spectral slot numbered j in the core r adjacent to c _i on the link l has been occupied, and taking 0 means it is not occupied;

   Calculate the available spectrum block according to the following formula

   

   crosstalk value

   

   

   Among them, n is the number of cores adjacent to the selected core c _i , L is the length of the current link l,

   

   is the average growth value of inter-core crosstalk per unit fiber length, k, r, β, and Λ are fiber parameters, which represent the coupling coefficient, bending radius, propagation coefficient and fiber-core spacing, respectively.
5. The space division multiplexing optical network dedicated protection spectrum allocation method of the data center according to claim 1 is characterized in that it also includes S9, when all connection requests have completed the inter-core crosstalk calculation and calculation of the working path and the dedicated protection path After spectrum allocation, the performance parameters of the network are evaluated.
6. A data center space division multiplexing optical network dedicated protection spectrum allocation system, characterized in that it includes:

   A network initialization module, the network initialization module is used to initialize the space division multiplexing elastic optical network oriented to the data center network;

   A connection request generation module, the connection request generation module is used to generate a connection request, wherein the connection request includes a data center source node and a data center target node;

   A route calculation module, the route calculation module is used to calculate the route of the connection request according to the source node of the data center and the destination node of the data center, and calculate a plurality of routes from the source node of the data center to the destination node of the data center for the connection request For the working path and the dedicated protection path that does not intersect with the working path, if the path is successfully established, the path with the shortest distance is selected in descending order as the working path and the dedicated protection path. If the path fails to be established, the connection request is judged as blocked;

   An idle spectrum availability selection module, the idle spectrum availability selection module is used to calculate the idle spectrum availability value of each fiber core on the working path, and select the fiber core with the largest idle spectrum availability value for transmission;

   A crosstalk constraint module, the crosstalk constraint module is used to search for an available spectrum block that meets the spectrum consistency and continuity constraints in the link selected from the working path and the fiber core used for transmission, if it can be found to meet the requirements available spectrum block, then calculate the crosstalk value of the available spectrum block by the fiber core, and judge whether the crosstalk value of the available spectrum block is greater than the maximum allowable crosstalk value of the link, if the judgment result is no, then reserve the available spectrum block, if the judgment result is yes, delete the available spectrum block, and continue to search until all the cores have been traversed, and when there is no available spectrum block that meets the crosstalk requirements in all the cores, the connection request is judged as blocked ; If the available spectrum blocks that meet the requirements cannot be found, return to S4, and select the next fiber core in descending order according to the free spectrum availability value, until all fiber cores have been traversed, and there is no available spectrum that meets the requirements in all fiber cores block, the connection request is judged as blocked;

   Spectrum allocation module, the spectrum allocation module is used to calculate the crosstalk value on all links of the working path of the available spectrum block meeting the crosstalk requirement in the fiber core used for transmission, and judge whether the crosstalk value on each link satisfies Threshold requirements, if the judgment result is yes, then establish a connection request, if the judgment result is no, then the connection request is judged to be blocked; repeat the process of crosstalk calculation and spectrum allocation on the working path, and complete the crosstalk calculation between cores on the dedicated protection path and spectrum allocation.
7. According to claim 6, the space-division multiplexing optical network dedicated protection spectrum allocation system of the data center is characterized in that, the available selection module of the idle spectrum comprises:

   An idle spectrum availability calculation unit, the idle spectrum availability calculation unit is used to calculate the idle spectrum availability value S _i of each fiber core i on the working path according to the following formula:

   

   Among them, |L| indicates the number of links on the current working path, |F| indicates the number of spectrum slots of each fiber core, S _k,i indicates that the number of kth free spectrum slots on core i is greater than or equal to FS The spectrum block of , FS represents the number of spectrum slots required by the connection request.
8. According to claim 6 or 7, the space division multiplexing optical network dedicated protection spectrum allocation system of the data center is characterized in that, the available selection module of the idle spectrum comprises:

   A fiber core selection unit, the fiber core selection unit is configured to arrange the fiber cores in descending order according to the idle spectrum availability value, and select the fiber core with the largest idle spectrum availability value for transmission.
9. The special protection spectrum allocation system for the space division multiplexing optical network of the data center according to claim 6, wherein the crosstalk constraint module includes:

   A crosstalk calculation module, the crosstalk calculation module is used to calculate the crosstalk value of the available spectrum block subjected to the fiber core, including:

   For available spectrum blocks

   

   According to the following formula, the spectrum slot number j in the available spectrum block is affected by the crosstalk of adjacent cores

   

   

   Among them, α and β are adjustable factors, n represents the core set adjacent to _ci ,

   

   is a binary variable, taking 1 means that the spectral slot numbered j in the core r adjacent to ci on the link _l has been occupied, and taking 0 means it is not occupied;

   Calculate the available spectrum block according to the following formula

   

   crosstalk value

   

   

   Among them, n is the number of cores adjacent to the selected core c _i , L is the length of the current link l,

   

   is the average growth value of inter-core crosstalk per unit fiber length, k, r, β, and Λ are fiber parameters, which represent the coupling coefficient, bending radius, propagation coefficient and fiber-core spacing, respectively.
10. The space division multiplexing optical network dedicated protection spectrum allocation system for data centers according to claim 6, further comprising:

    A network performance evaluation module, the network performance evaluation module is used to evaluate the performance parameters of the network after all the connection requests have completed the inter-core crosstalk calculation and frequency spectrum allocation on the working path and the dedicated protection path.

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