WO2020061790A1

WO2020061790A1 - Waveband switching method based on distance adaptation

Info

Publication number: WO2020061790A1
Application number: PCT/CN2018/107495
Authority: WO
Inventors: 陈彬; 英杰
Original assignee: 深圳大学
Priority date: 2018-09-26
Filing date: 2018-09-26
Publication date: 2020-04-02

Abstract

A waveband switching method based on distance adaptation, comprising: S1. constructing a waveband switching elastic optical network; S2. finding the waveband path in the waveband switching elastic optical network that can adapt to the most given requests; S3. selecting a corresponding modulation format for the adapted given request and allocating a corresponding spectrum resource; S4. repeating steps S1-S3 until all the given requests are allocated to corresponding spectrum resources. The implementation of the waveband switching method based on distance adaptation of the present invention can meet the minimum number of established waveband paths for wavelength service requests, so that the number of network ports for optical network service switching is as small as possible.

Description

Wavelength swapping method based on distance adaptation

Technical field

The present invention relates to the field of communication technology, and more particularly, to a method of waveband switching based on distance adaptation.

Background technique

WDM technology is a technology of channel multiplexing on optical fibers. The bandwidth of an optical fiber can reach 25000GHz, and the bandwidth of an optical signal is usually only a few gigahertz. The principle of wavelength division multiplexing is that the entire wavelength band is divided into several wavelength ranges, and each signal occupies a wavelength range for transmission. In essence, it is a variant of frequency division multiplexing used on optical channels, that is, optical frequency division multiplexing, but the technology and equipment used for optical multiplexing are different from electrical multiplexing. The frequency band has a very high bandwidth, so many channels can be divided and multiplexed.

However, in the existing WDM technology, when the channel spacing between different optical paths and the service signal bandwidth cannot be well matched, a large part of the spectrum interval resources cannot be fully utilized. And with the continuous development of various optical technologies, transmission rates close to Shannon's limit have made spectrum resources increasingly scarce.

Summary of the Invention

The technical problem to be solved by the present invention is to address the above-mentioned shortcomings of the prior art by providing a distance-adaptive waveband switching method that can effectively improve the utilization efficiency of network spectrum.

The technical solution adopted by the present invention to solve its technical problem is to construct a distance-based adaptive band exchange method, including:

S1. Construct a band-switched elastic optical network;

S2. Find a waveband path in the waveband switching elastic optical network that can be adapted to a maximum of the given requests;

S3. Select a corresponding modulation format for the adapted given request and allocate a corresponding spectrum resource;

S4. Repeat steps S1-S3 until all the given requests are allocated to corresponding spectrum resources, and calculate the number of switching ports required for all the given requests to successfully allocate spectrum resources.

In the method for waveband exchange based on distance adaptation according to the present invention, the step S1 further includes:

S11. A series-structured hierarchical optical cross-connection is set in each of the multiple network nodes;

S12. Construct the waveband switching elastic optical network based on the serial structure layered optical cross-connection based on the multiple network nodes.

In the distance-adaptive band switching method according to the present invention, the step S2 further includes:

S21. A flag bit that marks a given request for which resources are not successfully allocated is unsuccessfully allocated, and stores it in the first request set and gives the network topology of the band-switched elastic optical network and the spectral capacity of the optical fiber. information;

S22. Find the waveband path that can be adapted to the most of the given request in the waveband switching elastic optical network, and store all the given requests that are adapted to that waveband path to the second request set. in;

S23. For each elastic node of the waveband switching elastic optical network, find a maximum number of the waveband paths of the given request in the first waveband path set, and based on the most waves of the given request The number of hops in the band path and the number of fiber links that pass through it selects the band path;

S33. Delete the used waveband path from the first waveband path set and add it to the second waveband path set.

In the distance-adaptive band switching method according to the present invention, in the step S23, the plurality of given requests are found in the first set of band paths according to the shortest K path algorithm. Wave path.

In the distance-adaptive band switching method according to the present invention, the step S3 further includes:

S31. According to the uniqueness, spectrum continuity and spectrum available resource constraints of the given request being adapted, select a corresponding modulation format for the given request being adapted and allocate corresponding spectrum resources, and determine whether The allocation is successful. If the allocation fails, step S32 is performed; otherwise, step S33 is performed.

S32: Mark the flag bit of the given request as unsuccessfully allocated, and execute step S4;

S33. Mark a flag bit of the given request as successfully allocated, delete the successfully allocated wavelength resource from the first band path set, add it to the second band path set, and The given request is deleted from the first request set and added to the second request set, and step S4 is performed.

In the distance-adaptive band switching method according to the present invention, in step 31, a FIRST-FIT algorithm is used to select a corresponding modulation format for the given request to be adapted and allocate corresponding spectrum resources.

In the distance-adaptive band switching method according to the present invention, in step 31, a path-based distance adaptive modulation format is adopted as the corresponding modulation format.

In the distance-adaptive band switching method according to the present invention, the step S4 further includes:

S41. Repeat steps S1-S3 until all the given requests are allocated to the corresponding spectrum resources, and modify the flag bits of the given requests according to the allocation result;

S42. Calculate the number of switching ports required for all the given requests to successfully allocate spectrum resources.

Another technical solution adopted by the present invention to solve its technical problem is to construct a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the distance-based adaptive band exchange is implemented method.

The implementation of the distance-adaptive-based waveband switching method of the present invention can meet the minimum number of established waveband paths for wavelength service requests, so that the number of network ports for optical network service switching is as small as possible.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below with reference to the accompanying drawings and embodiments. In the drawings:

FIG. 1 is a principle block diagram of a first embodiment of a distance-adaptive band switching method according to the present invention; FIG.

Figure 2 shows a logical schematic diagram of a preferred band-switched elastic optical network;

Figure 3 shows a 6-node network topology;

FIG. 4 shows simulation results using the conventional TD-RSA method and the distance-adaptive band switching method based on the present invention.

detailed description

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

The present invention relates to a distance-adaptive waveband switching method, including: S1, constructing a waveband switching elastic optical network; S2, finding in the waveband switching elastic optical network that it can adapt to a maximum of the given request That band path; S3. Select the corresponding modulation format for the given request that is adapted and allocate the corresponding spectrum resource; S4. Repeat the steps S1-S3 until all the given requests are allocated to Corresponding spectrum resources. The implementation of the distance-adaptive-based waveband switching method of the present invention can meet the minimum number of established waveband paths for wavelength service requests, so that the number of network ports for optical network service switching is as small as possible.

FIG. 1 is a principle block diagram of a first embodiment of a method for optimizing a WDM optical network based on band switching according to the present invention. As shown in FIG. 1, in step S1, a band switching elastic optical network is constructed. In a preferred embodiment of the present invention, the step S1 further includes: S11. Setting up a series-structured hierarchical optical cross-connection in each of a plurality of network nodes; S12. Constructing a series-based hierarchical optical cross-connection based on the multiple network nodes Cross-connected band-switched elastic optical network.

Fig. 2 shows a logical schematic diagram of a layered optical cross-connect of a series structure. As shown in Figure 2, the optical path from the incoming fiber first reaches the 1 × 2WSS. If any service connection arrives at the destination node, it can be stripped from the band optical path and dropped to the local optical receiver. The remaining waveband optical paths will be sent to a Waveband Cross-Connect (WBXC) for band exchange. Finally, in the direction of the output fiber, the new service link on the road needs to be carried through the WSS. This separates the uplink and downlink functions of the service link from the cross-band connection, which is more suitable for band switching. It can be noted that in this preferred band-switching elastic optical network, a single optical channel cannot be switched from one band to another. This means that the connection request can only be routed by selecting one band path. Therefore, if path PA is a sub-path of path PB, all nodes on path PA will be included in path PB. Therefore, choosing the optimal waveband path becomes critical.

In step S2, a waveband path that can be adapted to a maximum of the given requests is found in the waveband switching elastic optical network. In a preferred embodiment of the present invention, the step S2 further includes: S21. A flag bit that marks a given request for which resources have not been successfully allocated is unsuccessfully allocated, and stores it in the first request set and gives the The network topology of the band-switched elastic optical network and the spectral capacity information of the optical fiber are described; S22. A band-path that can adapt to a maximum of the given requests is found in the band-switched elastic optical network, and the All given requests that match the waveband path are stored in the second request set; S23. For each flexible node of the waveband switching elastic optical network, find the most in the first waveband path set Each of the given requested band paths, and selects the band path based on the number of hops in the given requested band path and the number of fiber links passed; S33, the used band path is The first waveband path set is deleted and added to the second waveband path set. Preferably, in the step S23, according to the K shortest path algorithm, a maximum number of the band paths of the given request are found in the first set of band paths.

For example, specifically, the set Q is used to represent the first set of requests for a static given request that needs to be processed. In this step, the first consideration is the routing resource allocation of the static network. For all given requests, they are stored in the first request set Q. It is assumed that the flags of all given requests are 1, indicating that the given request has not been successfully allocated resources. The network topology and the spectral capacity of the fiber are given.

Secondly, it is considered that the band path between the entire network nodes is adapted to the known given request. Each band path can be adapted with multiple given requests. Set G to mark all given requests that fit into this waveband path. For each network node, according to K shortest path algorithm, each path can be adapted to identify a maximum of a given request path band (s _{_i,} d _i in the first wavelength band path set B, k _i ) If the corresponding hop number hop is the same, the smaller link through the fiber link is selected because it makes the number of ports used under the same conditions as small as possible. The used waveband path is deleted from the first waveband path set B, and the waveband path is added to the second waveband path set B '.

In step S3, a corresponding modulation format is selected for the given request being adapted, and a corresponding spectrum resource is allocated. In a preferred embodiment of the present invention, the step S3 further includes: S31. According to the uniqueness, spectrum continuity, and spectrum available resource constraints of the given request being adapted, Request to select the corresponding modulation format and allocate the corresponding spectrum resources, and determine whether the allocation is successful. If the allocation fails, go to step S32; otherwise, go to step S33; S32, mark the flag bit of the given request as unsuccessful allocation, and execute S4; S33. Mark the flag bit of the given request as successfully allocated, delete the successfully allocated wavelength resource from the first band path set, and add it to the second band path set, And delete the given request from the first request set and add it to the second request set, and execute step S4. Preferably, in step 31, the FIRST-FIT algorithm is used to select a corresponding modulation format for the given request to be adapted and allocate a corresponding spectrum resource. Preferably, in step 31, a path-based distance adaptive modulation format is adopted as the corresponding modulation format.

For example, according to the given request adapted in the second given request set G, under the constraints of uniqueness, spectrum continuity, and available spectrum resources, a First-Fit strategy is used to select a corresponding response for each given request that is adapted. The modulation format of the distance and the corresponding spectrum resource S are allocated, which is recorded as: AM-WBS-RSA-H algorithm. For a single modulation format, the S-WBS-RSA-H algorithm can be used. If the allocation is successful, it is identified that the given request in the adaptation has completed the allocation of spectrum resources, the given request is deleted from the first request set Q, and added to the third request set Q ', if the allocation fails , The given request is currently unable to obtain resources or is stored in the first request set Q, which indicates that it has not been processed and is waiting for the next adaptation of other shortest band paths of other network nodes. Here, for a given request that is adapted, as long as a given request is successfully allocated with the spectrum resource S, the corresponding band path is selected to be deleted from the first band path set B and added to the second wave In the band path set B ', a modulation method of the distance of the optical path of the band path is selected.

In a preferred embodiment of the present invention, the AM-WBS-RSA-H algorithm is as follows:

Constraint (1) indicates that any number of business connection requests use one path.

Constraint (2) indicates that the request (s, d, t) uses the spectrum resources of the k-th path to route these services containing continuous spectrum slots, and selects different modulation formats according to different optical path distance lengths.

Constraint (3) indicates that any number of spectrum resources on any link can only be used by at most one service connection request.

Constraint (4) is the continuity constraint of the spectrum, ensuring that the spectrum resources allocated to the service request are continuous.

Constraint (5) finds an adaptable band for each service request.

Constraint (6) ensures that each band contains a corresponding service connection request.

Constraint (7) is to minimize the number of ports used by the network.

In step S4, the steps S1-S3 are repeatedly performed until all the given requests are allocated to the corresponding spectrum resources. In a preferred embodiment of the present invention, the step S4 further includes: S41. Repeat the steps S1-S3 until all the given requests are allocated to corresponding spectrum resources, and modify the given resources according to the allocation result. Request flag; S42. Calculate the number of switching ports required for all the given requests to successfully allocate spectrum resources.

The following uses the 6-node network topology shown in FIG. 3 and the 11-node network topology shown in FIG. 4 to analyze the simulation results of the WDM optical network optimization method based on the band switching of the present invention. As shown in Figure 3, the 6-node network has 8 connections with an average node degree of 2.67. In the network, the two nodes associated with each connection are called a pair of adjacent nodes. Each pair of adjacent nodes is connected by two links with different transmission directions. Assume that each fiber has W wavelengths, and the bandwidth of each wavelength is 10Gbps. To make the simulation results general, the network traffic matrix is randomly generated. The service matrix generates services in a random manner, and the bandwidth of each service is 10Gbps. The K shortest path algorithm is used to calculate the K shortest paths between each node pair in advance. The smaller K, the lower the computational complexity. It is assumed here that K = 5 for 6 nodes. Regardless of signal reproduction and wavelength conversion. All optical paths have the same bandwidth. The processor used in the simulation is an Intel (r) Xeon (R) CPU E5-2640v3@2.60GHz and an HP personal computer with 64.0GB of RAM. In the VS2010 environment, ILOGCPLEX ^TM 12.6 linear programming software product from IBM was used to solve Algorithm to solve.

Figure 4 shows the simulation results using the traditional TD-RSA method and the distance-based adaptive band switching method of the present invention. The traditional routing spectrum allocation TD-RSA algorithm and the band switching routing based on the ILP algorithm model are analyzed and compared. The relationship between the number of OXCs optical switching ports required for routing all service connection requests between the spectrum allocation single modulation format S-WBS-RSA-ILP algorithm and the distance-based adaptive AM-WBS-RSA-ILP algorithm. It can be obtained by constraint expression (7).

In FIG. 4, the spectrum resource S = 48, when the number of services CRs = 1, the number of OXC switching ports used by the TD-RSA algorithm based on traditional routing spectrum allocation is 62, and the S-WBS-RSA-ILP of a single modulation format The number of OXC optical switching ports required by the algorithm and the distance-adaptive AM-WBS-RSA-ILP algorithm to route all service connection requests is 10 and 10, saving about 84% of the number of ports.

Another embodiment of the present invention provides a machine-readable memory and / or storage medium, and the machine code and / or computer program stored therein includes at least one code segment, which is executed by a machine and / or a computer such that the machine and / or Or the computer executes each step of the distance-based adaptive band switching method described in this application.

Therefore, the present invention can be implemented by hardware, software, or a combination of software and hardware. The invention may be implemented in a centralized manner in at least one computer system or in a decentralized manner by different parts distributed among several interconnected computer systems. Any computer system or other device that can implement the method of the present invention is applicable. The combination of commonly used software and hardware can be a general-purpose computer system with a computer program installed, and the computer system can be controlled to run according to the method of the present invention by installing and executing the program.

The present invention can also be implemented by a computer program product. The program includes all the features capable of implementing the method of the present invention. When installed in a computer system, the method of the present invention can be implemented. The computer program in this document refers to: any expression that can use a set of instructions written in any programming language, code, or symbol, which enables the system to have information processing capabilities to directly implement specific functions, or to perform A specific function is achieved after describing one or two steps: a) conversion to other languages, codes or symbols; b) reproduction in different formats.

Although the present invention is described through specific embodiments, those skilled in the art should understand that various changes and equivalent substitutions can be made to the present invention without departing from the scope of the present invention. In addition, for the specific situation or material, various modifications can be made to the invention without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all implementations falling within the scope of the claims of the present invention.

Claims

A method of waveband exchange based on distance adaptation, which is characterized by:

S1. Construct a band-switched elastic optical network;

S2. Find a waveband path in the waveband switching elastic optical network that can be adapted to a maximum of the given requests;

S3. Select a corresponding modulation format for the adapted given request and allocate a corresponding spectrum resource;

S4. Repeat steps S1-S3 until all the given requests are allocated to corresponding spectrum resources.
The method of claim 1, wherein the step S1 further comprises:

S11. A series-structured hierarchical optical cross-connection is set in each of the multiple network nodes;

S12. Construct the waveband switching elastic optical network based on the serial structure layered optical cross-connection based on the multiple network nodes.
The method of claim 1, wherein the step S2 further comprises:

S21. A flag bit that marks a given request for which resources are not successfully allocated is unsuccessfully allocated, and stores it in the first request set and gives the network topology of the band-switched elastic optical network and the spectral capacity of the optical fiber. information;

S22. Find the waveband path that can be adapted to the most of the given request in the waveband switching elastic optical network, and store all the given requests that are adapted to that waveband path to the second request set. in;

S23. For each elastic node of the waveband switching elastic optical network, find a maximum number of the waveband paths of the given request in the first waveband path set, and based on the most waves of the given request The number of hops in the band path and the number of fiber links that pass through it selects the band path;

S33. Delete the used waveband path from the first waveband path set and add it to the second waveband path set.
The method according to claim 2, wherein in step S23, a maximum number of locations in the first set of waveband paths are found according to the K-path shortest algorithm. Describe the band path for a given request.
The method of claim 1, wherein the step S3 further comprises:

S31. According to the uniqueness, spectrum continuity, and available spectrum resource constraints of the given request being adapted, select a corresponding modulation format for the given request being adapted and allocate corresponding spectrum resources, and determine whether The allocation is successful. If the allocation fails, step S32 is performed; otherwise, step S33 is performed.

S32: Mark the flag bit of the given request as unsuccessfully allocated, and execute step S4;

S33. Mark a flag bit of the given request as successfully allocated, delete the successfully allocated wavelength resource from the first band path set, add it to the second band path set, and The given request is deleted from the first request set and added to the second request set, and step S4 is performed.
The method for optimizing a WDM optical network based on band switching according to claim 4, characterized in that in step 31, a FIRST-FIT algorithm is used to select a corresponding modulation format for the given request to be adapted and assign the corresponding modulation format. Of spectrum resources.
The method for optimizing a WDM optical network based on band switching according to claim 5, characterized in that, in step 31, a path-based distance adaptive modulation format is adopted as the corresponding modulation format.
The method for optimizing a WDM optical network based on band switching according to claim 1, wherein the step S4 further comprises:

S41. Repeat steps S1-S3 until all the given requests are allocated to the corresponding spectrum resources, and modify the flag bits of the given requests according to the allocation result;

S42. Calculate the number of switching ports required for all the given requests to successfully allocate spectrum resources.
A computer-readable storage medium having stored thereon a computer program, characterized in that when the program is executed by a processor, the waveband based on distance adaptation according to any one of claims 1-7 is realized Exchange method.