Service function chain arrangement method and device suitable for low earth orbit satellite network

Abstract

The invention provides a service function chain arrangement method and device suitable for a low earth orbit satellite network, relates to the technical field of low earth orbit satellite communication, and is essentially a distributed point-by-point service function chain arrangement scheme. A series of virtual network functions (VNFs) are sequentially embedded into a series of adjacent satellite nodes to orchestrate service function chain (SFC) requests, so that the computing power requirement on the integrated controller is relatively low, and the method is suitable for a large-scale low-orbit satellite network without a stable integrated controller. In the distributed deployment process of the VNF, a selectable satellite node set for deploying the next VNF is firstly determined, and then an actor reviewer network model of an integrated decision converter is used to process the recently deployed C VNF trajectory points so as to select a second satellite node for deploying the next VNF from the selectable satellite node set. That is, the method can determine a more robust VNF deployment decision based on global context information, and avoids a local optimum problem.

Description

Technical Field

[0001] The present invention relates to the technical field of low-orbit satellite communications, and in particular to a service function chain arrangement method and device suitable for a low-orbit satellite network. Background Art

[0002] In recent years, low-orbit satellite networks have attracted widespread attention from academia and industry. Low-orbit satellite networks offer the advantages of wide coverage, large-scale access, fast response, and cost-effective deployment. As a result, their utilization has grown exponentially and significantly. However, with the rapid expansion of low-orbit satellite network applications, it has become increasingly important to meet business differentiation based on user needs. Each application has unique quality of service requirements in terms of data rate, latency, reliability, and coverage.

[0003] Advances in service function chaining have emerged as a key technology to address this challenge. Service function chaining is a networking paradigm concept that groups virtual network functions such as firewalls, load balancers, deep packet inspection, etc. together in a predefined order to apply a set of network services. By orchestrating service function chains, traffic can be directed through the required network functions in a specific order to achieve service-specific quality of service requirements. Orchestrating service function chaining involves managing and coordinating various virtual network functions to achieve the required service functions and ensure seamless operation. However, finding the optimal service function chaining orchestration strategy is a challenging task due to the exponential growth in the possible combinations and permutations of virtual network functions.

[0004] In the prior art, some researchers have proposed modeling the 5G network service function chain orchestration problem as an integer linear programming problem and deploying a rounding-based approximation algorithm on a centralized controller to generate a solution. However, traditional methods rely heavily on a centralized controller to generate the optimal strategy. This algorithm requires high computing power from the controller and is not suitable for large-scale low-orbit satellite networks without a stable centralized controller. Summary of the invention

[0005] The purpose of the present invention is to provide a service function chain orchestration method and device suitable for low-orbit satellite networks, so as to alleviate the technical problems of existing service function chain orchestration methods, namely, high requirements on the computing power of the centralized controller and unsuitability for large-scale low-orbit satellite networks without a stable centralized controller.

[0006] In a first aspect, the present invention provides a service function chain orchestration method suitable for a low-orbit satellite network, including: step S102, receiving a service function chain SFC request and resetting the low-orbit satellite network environment; wherein the SFC request includes: a source base station, a destination base station and a plurality of virtual network functions VNFs orchestrated in a specified order; step S104, calculating an orchestration direction unit vector of the SFC request according to the location coordinates of the source base station and the location coordinates of the destination base station; step S106, randomly selecting a satellite node within the communication range of the source base station, and deploying the first VNF ​​on the satellite node when it is determined that the satellite node meets the deployment conditions of the first VNF ​​in the SFC request; step S108, based on the orchestration direction unit vector, the location coordinates of the first satellite node that currently deploys the last VNF ​​and the neighboring satellite nodes of the first satellite node; The position coordinates of the star node are used to determine the set of optional satellite nodes for deploying the next VNF; step S110, using the actor-critic network model of the integrated decision transformer to process the C VNF trajectory points that have been deployed recently to select the second satellite node for deploying the next VNF ​​from the set of optional satellite nodes; wherein each VNF trajectory point includes: the satellite node number of the deployed VNF, the resource status of the satellite node, and the reward obtained by deploying the VNF; step S112, when it is determined that the second satellite node meets the deployment conditions of the next VNF, the SFC orchestration duration is calculated; step S114, when it is determined that the SFC orchestration duration is less than or equal to the preset duration threshold, and the deployment of all VNFs in the SFC request has not been completed, return to step S108 until the deployment of all VNFs in the SFC request is completed.

[0007] Optionally, based on the unit vector of the orchestration direction, the position coordinates of the first satellite node of the last deployed VNF and the position coordinates of the neighbor satellite nodes of the first satellite node, a set of optional satellite nodes for deploying the next VNF ​​is determined, including: based on the equal division principle and the position coordinates of the first satellite node, the spherical area covered by the communication of the first satellite node is divided into four quadrants to obtain four communication areas, and the center point coordinates of each communication area are determined; based on the center point coordinates of each communication area and the position coordinates of the first satellite node, the unit vector of each communication area is calculated; the dot product of the unit vector of each communication area and the unit vector of the orchestration direction is calculated, and the four communication areas are sorted in descending order based on the dot product result; when it is determined that there is a neighbor satellite node in the target communication area ranked first based on the position coordinates of the neighbor satellite node of the first satellite node, a set of optional satellite nodes is constructed based on all the neighbor satellite nodes in the target communication area; otherwise, the communication areas ranked later are selected in order until the set of optional satellite nodes is determined.

[0008] Optionally, calculate the SFC scheduling duration, including: using the formula Calculate the SFC scheduling duration; where, Indicates SFC request The SFC arrangement time, Indicates the time consumption of the current round of scheduling. Indicates the time consumption of historical round scheduling; , L represents the set of physical network links, Represents a collection of virtual network links. represents the single-hop transmission delay from satellite node u to satellite node v in time slot t, Indicates VNF virtual link Deployed on the physical network link uv, Indicates VNF virtual link Not deployed on the physical network link uv, represents the processing delay of satellite node i, indicates that the kth VNF is deployed at satellite node i, indicates that the kth VNF is not deployed at satellite node i, represents the total number of satellites in the low-orbit satellite network, Represents the set of all VNFs in the SFC request.

[0009] Optionally, after selecting the second satellite node for deploying the next VNF ​​from the optional satellite node set, the method further includes: step S111, based on the formula Update the network parameters of the actor network in the actor-critic network model; based on the formula Update the network parameters of the critic network; where, represents the network parameters of the actor network, represents the resource status of satellite node i in the current time slot t, Indicates that the VNF is deployed on satellite node i at the current time slot t, Representing the old strategy of the actor network , , The importance weights representing the relative differences between the new and old strategies of the actor network, represents the clipping hyperparameter, A new strategy for representing actor networks, , represents the advantage function calculated by TD error, represents the discount factor, represents the reward obtained by deploying VNF on satellite node m in time slot x, and t-u+1=C, represents the value function of the critic network in the actor-critic network model, represents the network parameters of the critic network.

[0010] Optionally, after selecting a second satellite node for deploying the next VNF ​​from the optional satellite node set, it also includes: step S113, when it is determined that the second satellite node does not meet the deployment conditions of the next VNF, releasing all deployed VNFs in the low-orbit satellite network, returning to step S106, and updating the SFC orchestration duration.

[0011] Optionally, after calculating the SFC scheduling duration, the method further includes: step S115, when it is determined that the SFC scheduling duration is greater than a preset duration threshold, determining that the SFC request scheduling fails.

[0012] In a second aspect, the present invention provides a service function chain orchestration device suitable for a low-orbit satellite network, including: a receiving and resetting module, used to receive a service function chain SFC request and reset the low-orbit satellite network environment; wherein the SFC request includes: a source base station, a destination base station and a plurality of virtual network functions VNFs orchestrated in a specified order; a first calculation module, used to calculate the orchestration direction unit vector of the SFC request according to the location coordinates of the source base station and the location coordinates of the destination base station; a deployment module, used to randomly select a satellite node within the communication range of the source base station, and deploy the first VNF ​​on the satellite node when it is determined that the satellite node meets the deployment conditions of the first VNF ​​in the SFC request; a determination module, used to determine the location coordinates of the first satellite node based on the orchestration direction unit vector, the location coordinates of the first satellite node that currently deployed the last VNF, and the neighbors of the first satellite node. The location coordinates of the satellite node are used to determine the set of optional satellite nodes for deploying the next VNF; a selection module is used to process the C VNF trajectory points that have been deployed recently using the actor-critic network model with an integrated decision transformer to select a second satellite node from the set of optional satellite nodes for deploying the next VNF; wherein each VNF trajectory point includes: the satellite node number of the deployed VNF, the resource status of the satellite node, and the reward obtained by deploying the VNF; a second calculation module is used to calculate the SFC orchestration duration when it is determined that the second satellite node meets the deployment conditions of the next VNF; a return module is used to return to the call determination module when it is determined that the SFC orchestration duration is less than or equal to a preset duration threshold and the deployment of all VNFs in the SFC request has not been completed, until the deployment of all VNFs in the SFC request is completed.

[0013] Optionally, the determination module is specifically used to: divide the spherical area covered by the first satellite node communication into four quadrants based on the equal division principle and the position coordinates of the first satellite node, obtain four communication areas, and determine the center point coordinates of each communication area; calculate the unit vector of each communication area based on the center point coordinates of each communication area and the position coordinates of the first satellite node; calculate the dot product of the unit vector of each communication area and the unit vector of the arrangement direction, and sort the four communication areas in descending order based on the dot product result; when it is determined that there is a neighbor satellite node in the target communication area ranked first based on the position coordinates of the neighbor satellite nodes of the first satellite node, construct a set of optional satellite nodes based on all the neighbor satellite nodes in the target communication area; otherwise, select the communication areas ranked later in order until the set of optional satellite nodes is determined.

[0014] In a third aspect, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, it implements the service function chain orchestration method applicable to a low-orbit satellite network according to any one of the aforementioned implementation modes.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the service function chain orchestration method applicable to a low-orbit satellite network of any one of the aforementioned implementation modes is implemented.

[0016] The present invention provides a service function chain orchestration method suitable for low-orbit satellite networks. The essence of the method is a distributed point-by-point service function chain orchestration scheme, which orchestrates service function chain SFC requests by sequentially embedding a series of virtual network functions VNFs into a series of adjacent satellite nodes. Therefore, the computing power requirements for the centralized controller are relatively low, and it is suitable for large-scale low-orbit satellite networks without stable centralized controllers. In the distributed deployment process of VNF, the set of optional satellite nodes for deploying the next VNF ​​is first determined, and then the actor-critic network model with integrated decision transformer is used to process the most recently deployed C VNF trajectory points to select the second satellite node for deploying the next VNF ​​in the set of optional satellite nodes. That is, the method can determine a more robust VNF ​​deployment decision based on global context information, reducing the local optimal problem that may be caused by relying only on the current state. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a schematic diagram of the service function chain SFC orchestration architecture; Figure 2 A flow chart of a service function chain arrangement method applicable to a low-orbit satellite network provided in an embodiment of the present invention; Figure 3 A schematic diagram of dividing the spherical area covered by the communication of the first satellite node into equal parts provided by an embodiment of the present invention; Figure 4 A framework diagram of the ACDT algorithm provided in an embodiment of the present invention; Figure 5 This is a comparison chart of the total reward value curves of four different algorithms under 13 low-orbit satellites; Figure 6 This is a comparison chart of the total reward value curves of four different algorithms under 15 low-orbit satellites; Figure 7 This is a comparison chart of the total reward value curves of four different algorithms under 17 low-orbit satellites; Figure 8 The following is a comparison chart of the SFC arrangement success rate of four different algorithms under 13 low-orbit satellites; Fig. 9 The following is a comparison chart of the SFC arrangement success rate of four different algorithms under 15 low-orbit satellites; Fig.10 The following is a comparison chart of the SFC arrangement success rate of four different algorithms under 17 low-orbit satellites; Fig.11 A functional module diagram of a service function chain arrangement device applicable to a low-orbit satellite network provided by an embodiment of the present invention; Fig.12 A schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0022] Figure 1 The schematic diagram of the service function chain SFC orchestration architecture is as follows: Figure 1 As shown in Figure 1, the SFC orchestration framework can be divided into four layers: application layer, service layer, virtualization layer, and physical layer. The application layer publishes different applications according to different scenarios, such as environmental monitoring, disaster relief, and intelligent scheduling. The service layer converts these applications into SFC requests, which contain various non-embedded virtual network function requests VNFs orchestrated in a specified order, and each SFC request has a service source point and a service end point. The virtualization layer is responsible for matching network resources with SFC resource requests. The low-orbit satellite network is abstracted as a resource pool, where virtual resources can be dynamically allocated to meet the resource requirements of SFC. Finally, the physical layer corresponds to the low-orbit satellite network environment composed of multiple low-orbit satellite nodes and base stations. As edge nodes, base stations drive the SFC request orchestration process. Some base stations, as source nodes, publish SFC requests to their neighboring low-orbit satellite nodes, while other base stations, as target nodes, receive SFC orchestration information from the last virtual network function embedded node. These four layers are interrelated to form a closed-loop optimization.

[0023] In order to meet the service function chain orchestration requirements of a large-scale low-orbit satellite network without a stable centralized controller, an embodiment of the present invention proposes a distributed point-by-point service function chain orchestration solution, which orchestrates service function chain requests by sequentially embedding (i.e., deploying) a series of virtual network functions (VNFs) into a series of adjacent nodes. The method provided by the embodiment of the present invention is described in detail below.

[0024] Embodiment 1 Figure 2 A flow chart of a service function chain arrangement method applicable to a low-orbit satellite network provided in an embodiment of the present invention is shown in FIG. Figure 2 As shown, the method specifically comprises the following steps: Step S102, receiving a service function chain SFC request and resetting the low-orbit satellite network environment.

[0025] The SFC request includes: a source base station, a destination base station, and multiple virtual network functions VNFs arranged in a specified order.

[0026] Specifically, the low-orbit satellite network environment will be reset after receiving a new SFC request. Resetting can also be understood as initialization, and the parameters such as computing resources, storage space and energy consumption of each low-orbit satellite will be reassigned. It can be expressed as ,in, represents the source base station, Indicates the destination base station, Represents multiple virtual network functions VNFs arranged in a specified order. , represents the kth VNF request, each VNF request has a corresponding resource requirement, Includes memory requirements for all VNF requests, Includes CPU requirements requested by all VNFs, Includes bandwidth requirements requested by all VNFs, Includes the power requirements of all VNF requests, Indicates the maximum scheduling time, that is, the preset duration threshold. If the total scheduling time of SFC exceeds , it is determined that the SFC request has failed to be scheduled due to a scheduling timeout.

[0027] The embodiment of the present invention models the SFC request orchestration process in a distributed point-by-point solution. Starting from the source base station, iteratively searches for adjacent low-orbit satellite nodes to embed each VNF until the SFC request is embedded and the orchestration information of the destination base station is collected.

[0028] Step S104: Calculate the scheduling direction unit vector of the SFC request according to the location coordinates of the source base station and the location coordinates of the destination base station.

[0029] Considering that satellite nodes in low-orbit satellite networks often have high mobility, an embodiment of the present invention proposes to specify the orchestration direction of the SFC request to provide guidance for satellite area selection when deploying adjacent VNFs. After determining the source base station and the destination base station of the SFC request, the unit vector of the orchestration direction of the SFC request can be calculated based on the location coordinates of the source base station and the location coordinates of the destination base station. .

[0030] ,in, Indicates the distance between the source base station and the destination base station, represents the location coordinates of the source base station, Indicates the location coordinates of the destination base station.

[0031] Step S106: randomly select a satellite node within the communication range of the source base station, and deploy the first VNF ​​on the satellite node when it is determined that the satellite node meets the deployment conditions of the first VNF ​​in the SFC request.

[0032] When deploying VNF, first randomly select a low-orbit satellite node within the communication range of the source base station, and determine whether it meets the deployment conditions of the first VNF ​​in the SFC request. In an embodiment of the present invention, the deployment conditions of the VNF are specifically the resource requirements of the VNF. If the remaining resources of the satellite node can meet the requirements of the first VNF, the first VNF ​​can be deployed on the satellite node. Otherwise, randomly select a satellite node within the communication range of the source base station again. If a satellite node that meets the deployment conditions of the first VNF ​​cannot be found after traversing all satellite nodes within the communication range of the source base station, it is determined that the current SFC request orchestration has failed.

[0033] Step S108, determining a set of optional satellite nodes for deploying the next VNF ​​based on the orchestration direction unit vector, the position coordinates of the first satellite node that currently deploys the last VNF, and the position coordinates of the neighboring satellite nodes of the first satellite node.

[0034] It can be seen from the steps above that the unit vector of the orchestration direction of the SFC request can be calculated according to the location of the source base station and the location of the destination base station, that is, the deployment direction of a series of VNFs in the SFC request can be determined. Therefore, after determining the satellite node for deploying the first VNF, the satellite node for deploying the second VNF should not deviate from the above deployment direction in principle. In addition, it should be noted that in the embodiment of the present invention, a satellite node can only deploy one VNF request, and a VNF request can only be deployed on one satellite node.

[0035] At the end of step S106, only the first VNF ​​is successfully deployed. Therefore, when step S108 is executed for the first time, the first satellite node that currently deploys the last VNF ​​is the satellite node that deploys the first VNF. In order to determine the satellite node for deploying the next VNF, the embodiment of the present invention models the SFC orchestration problem as a decentralized partially observable Markov decision process, and proposes a communication area partitioning method to limit its deployable area. Specifically, the communication coverage area of ​​the first satellite node is partitioned, and then an area with the highest similarity to the unit vector of the orchestration direction is selected therefrom. If there is a neighbor satellite node of the first satellite node in the area, the satellite node for deploying the next VNF ​​should be selected in the area, that is, the neighbor satellite nodes (of the first satellite node) located in the area constitute a set of optional satellite nodes.

[0036] Step S110, using the actor-critic network model with integrated decision transformer to process the most recently deployed C VNF trajectory points to select a second satellite node for deploying the next VNF ​​from the set of optional satellite nodes.

[0037] Each VNF trajectory point includes: the satellite node number where the VNF is deployed, the resource status of the satellite node, and the reward obtained by deploying the VNF. The embodiment of the present invention does not specifically limit the calculation method of the reward, and the user can set it according to actual needs, for example, the reward is inversely proportional to the communication delay and resource consumption.

[0038] After the optional satellite node set is determined, the embodiment of the present invention uses the most recently deployed C VNF trajectory points as the input of the actor-critic network model with integrated decision transformer. The action space of the agent in the model is the above optional satellite node set, and the output of the actor-critic network model is the second satellite node used to deploy the next VNF. The embodiment of the present invention does not specifically limit the value of C. The larger the value of C, the larger the calculation amount of the model and the higher the decision quality of the satellite node; the smaller the value of C, the smaller the calculation amount of the model and the lower the decision quality of the satellite node. Therefore, the user can set the value of C according to actual needs. Optionally, C is 4. In the initial stage of SFC deployment, when the number of VNF trajectory points is less than C, it is filled with zero values. After the number of trajectory points increases, it is gradually replaced with real trajectory points, but only the most recently deployed C trajectory points are retained.

[0039] In the traditional model, the state of the agent is its local observation state. If only the observation value (resource state, etc.) of the satellite node is used as the agent state, it is impossible to capture the changes in the low-orbit satellite network in the time dimension, and it is impossible to use past decision and reward information to correct the current decision. Compared with the traditional model, in the embodiment of the present invention, the state of the agent in the actor-critic network model is the C VNF trajectory points that have been deployed recently. The trajectory (that is, C VNF trajectory points) contains historical information of multiple time steps, which can help the system capture the changing trend of node resources and topological states in dynamic networks. For example, if the bandwidth usage of a satellite node has gradually increased in the past few steps, it may indicate that the node is about to run out of resources. The trajectory can help the agent predict this trend and avoid selecting it.

[0040] In addition, trajectories can capture the long-term impact of past decisions and optimize global strategies. For example, if a satellite node has been selected as an embedding node many times in the past and caused high latency, the system can learn to avoid selecting similar nodes, thereby supporting long-term dependency modeling. Through trajectory modeling, the agent can make more robust decisions based on global context information and reduce the local optimality problem that may be caused by relying solely on the current state.

[0041] Step S112, when it is determined that the second satellite node meets the deployment conditions of the next VNF, calculate the SFC orchestration duration.

[0042] It is known that each VNF has corresponding deployment conditions. If the second satellite node selected by the actor-critic network model meets the deployment conditions of the next VNF, it is necessary to further consider whether the SFC orchestration duration up to now meets the requirements. In this embodiment of the present invention, the SFC orchestration duration is the sum of the historical round orchestration time consumption and the current round orchestration time consumption.

[0043] Step S114, when it is determined that the SFC orchestration duration is less than or equal to the preset duration threshold and the deployment of all VNFs in the SFC request has not been completed, return to step S108 until the deployment of all VNFs in the SFC request is completed.

[0044] After the second VNF deployment is completed, the first satellite node of the last deployed VNF is updated from the satellite node for deploying the first VNF ​​to the satellite node for deploying the second VNF. Next, the satellite node for deploying the second VNF is used as the base point to determine the set of optional satellite nodes for deploying the next VNF. By analogy, the above steps S108 to S114 are repeated until all VNFs in the SFC request are deployed, and only when the satellite node for deploying the last VNF ​​in the SFC request can communicate with the destination base station can the SFC request be determined to be deployed successfully.

[0045] The embodiment of the present invention provides a service function chain orchestration method suitable for low-orbit satellite networks. The essence of the method is a distributed point-by-point service function chain orchestration scheme, which orchestrates service function chain SFC requests by sequentially embedding a series of virtual network functions VNFs into a series of adjacent satellite nodes. Therefore, the computing power requirements for the centralized controller are relatively low, and it is suitable for large-scale low-orbit satellite networks without stable centralized controllers. In the distributed deployment process of VNF, the set of optional satellite nodes for deploying the next VNF ​​is first determined, and then the actor-critic network model with integrated decision transformer is used to process the most recently deployed C VNF trajectory points to select the second satellite node for deploying the next VNF ​​in the set of optional satellite nodes. That is, the method can determine a more robust VNF ​​deployment decision based on global context information, reducing the local optimal problem that may be caused by relying only on the current state.

[0046] In an optional implementation, the above step S108, based on the orchestration direction unit vector, the position coordinates of the first satellite node that currently deploys the last VNF, and the position coordinates of the neighboring satellite nodes of the first satellite node, determines the set of optional satellite nodes for deploying the next VNF, and specifically includes the following steps: Step S1081, based on the equal division principle and the position coordinates of the first satellite node, the spherical area covered by the communication of the first satellite node is divided into four quadrants to obtain four communication areas, and the coordinates of the center point of each communication area are determined.

[0047] Step S1082: Calculate the unit vector of each communication area based on the center point coordinates of each communication area and the position coordinates of the first satellite node.

[0048] Step S1083, calculating the dot product of the unit vector of each communication area and the unit vector of the arrangement direction, and sorting the four communication areas in descending order based on the dot product result.

[0049] If it is determined based on the position coordinates of the neighbor satellite nodes of the first satellite node that there is a neighbor satellite node in the target communication area ranked first, the following step S1084 is executed; otherwise, the following step S1085 is executed.

[0050] Step S1084: construct a selectable satellite node set based on all neighbor satellite nodes in the target communication area.

[0051] Step S1085, selecting the communication areas with lower ranking in order until the optional satellite node set is determined.

[0052] From the above description, it can be seen that the communication area division method is used in the embodiment of the present invention to simply calculate the business process direction of the SFC request, thereby limiting the deployable area of ​​the next VNF ​​to be deployed. Specifically, Figure 3 As shown, the spherical area (3D space) covered by the first satellite node communication is first divided into four communication areas The size of the spherical area covered by each satellite node communication is a known quantity. According to the position coordinates of the satellite node, the coordinates of the center point of each communication area can be determined by mathematical methods.

[0053] Next, according to the position coordinates of the first satellite node and the coordinates of the center point of each communication area, the unit vector of each communication area can be calculated by referring to the calculation method of the arrangement direction unit vector. , that is, the position vector difference between the first satellite node and the center point of each area. Then the deployable area ranking result is generated by vector dot product and descending sorting. The first ranked target communication area is represented as .

[0054] if If there are neighbor satellite nodes in All neighbor satellite nodes in constitute the optional satellite node set; if If there is no neighbor satellite node in the target area, the second ranked area is selected as the new target communication area. If the new If there are neighbor satellite nodes in All neighbor satellite nodes in constitute the optional satellite node set; otherwise, the third-ranked area is selected in sequence, and so on, until the optional satellite node set is determined.

[0055] In an optional implementation, after selecting a second satellite node for deploying the next VNF ​​from the optional satellite node set, the method of the present invention further includes the following steps: Step S113, when it is determined that the second satellite node does not meet the deployment conditions of the next VNF, release all deployed VNFs in the low-orbit satellite network, return to step S106, and update the SFC orchestration duration.

[0056] Specifically, in an embodiment of the present invention, the SFC request can be re-arranged through multiple rounds. If the second satellite node selected by the actor-critic network model cannot meet the deployment conditions of the next VNF, the SFC arrangement of the current round fails, the current round ends, and a new round begins. At the beginning of the new round, all embedded VNFs on each low-orbit satellite node in the previous round need to be released, and then return to the above step 106, that is, reselect the satellite node for deploying the first VNF ​​within the communication range of the source base station, and execute the subsequent method flow. In addition, the time consumed by the business process that failed to be arranged in the current round needs to be accumulated to the SFC arrangement duration.

[0057] In an optional implementation, in the above step S112, calculating the SFC scheduling duration specifically includes the following contents: Using the formula Calculate the SFC scheduling duration; where, Indicates SFC request The SFC arrangement time, Indicates the time consumption of the current round of scheduling. Indicates the time consumption of historical round scheduling.

[0058] , L represents the set of physical network links, Represents a collection of virtual network links. represents the single-hop transmission delay from satellite node u to satellite node v in time slot t, Indicates VNF virtual link Deployed on the physical network link uv, Indicates VNF virtual link Not deployed on the physical network link uv, represents the processing delay of satellite node i, indicates that the kth VNF is deployed at satellite node i, indicates that the kth VNF is not deployed at satellite node i, represents the total number of satellites in the low-orbit satellite network, Represents the set of all VNFs in the SFC request.

[0059] Based on the above formula, we can see that for the current round, the time consumption mainly includes the transmission delay and the processing delay caused by the multi-hop orchestration process. For any link embedded in any adjacent VNF ​​request , the transmission delay can be expressed as ,in, is the size of the data packet transmitted on the physical network link uv, Indicates the bandwidth of the physical network link uv.

[0060] In the embodiment of the present invention, after calculating the SFC scheduling duration, the method of the present invention further comprises the following steps: Step S115, if it is determined that the SFC scheduling duration is greater than the preset duration threshold, it is determined that the SFC request scheduling fails. That is, if , it is determined that the SFC request scheduling fails.

[0061] In order to generate a stable SFC scheduling strategy in a low-orbit satellite network, an embodiment of the present invention proposes an ACDT (Actor-Critical Decision Transformer) algorithm, which is a distributed multi-agent reinforcement learning algorithm. The decision transformer network is integrated into the actor-critic network to obtain an actor-critic network model with integrated decision transformer. Figure 4 A framework diagram of the ACDT algorithm provided in an embodiment of the present invention.

[0062] The decision transformer is a popular neural network model that can solve sequential decision problems by modeling contextual trajectories. The embodiment of the present invention proposes a simplified decision transformer model for stable SFC orchestration in low-orbit satellite networks. It consists of a position encoding model and an attention-based model. The position encoding model uses a position encoding layer and an embedding layer to encode trajectory sequences at different positions. It consists of two linear transformations connected by a ReLU activation function: ,in and represents the weight, and Indicates deviation.

[0063] The attention-based model is able to capture the contextual time-dependent features of the input trajectory. Mapping to vector combinations For the trajectory Each trajectory point in , the array point attention model converts it into a query vector through three different linear transformations , key vector Sum value vector : .

[0064] , , and d represent the query vector , key vector , value vector and trajectory points Afterwards, the array point attention model combines all the tag-based vectors along the time dimension to generate a complete vector combination : ;in, Representation trajectory The dimension of , on this basis, the attention is calculated through the masking mechanism: ;in, It is used to prevent the softmax function from falling into the gradient minimum solution, and M is the mask matrix.

[0065] When the above neural network model is applied to SFC orchestration in low-orbit satellite networks, for the SFC distributed point-by-point orchestration process, the decision transformer network extracts the C most recently deployed VNF trajectory points according to the chronological order. Each VNF trajectory point includes: the satellite node number where the VNF is deployed, the resource status of the satellite node, and the reward obtained by deploying the VNF, thereby forming a context trajectory. , t represents the current time slot. In the embodiment of the present invention, , t-u+1=C, that is, using C VNF trajectory points, trajectory The overall context length is C-1, where , Indicates that VNF ​​is deployed on satellite node i in time slot u. represents the resource status of satellite node i in time slot u, Indicates that VNF ​​deployed on satellite node i in time slot u is rewarded. The initial trajectory needs to be filled with zero values ​​in the initial stage of model application. , and gradually fill the trajectory with real trajectory points as VNFs are deployed.

[0066] In the actor-critic network, each agent shares the same Actor-Critic network to be trained together in a distributed manner. The temporary local network state features from the sequentially embedded satellite nodes are included to promote the algorithm to converge to the global optimum, that is, the algorithm can form a stable SFC orchestration strategy. In the actor-critic network, the actor network is based on the trajectories of the C most recently deployed VNF trajectory points. The action policy is generated adaptively, while the critic evaluates and guides the action to converge to the global optimum through the output value. ,in, represents the network parameters of the actor network, Representation using action space The probability distribution on the action space That is, all neighbor satellite nodes in Z(i), that is, the set of optional satellite nodes.

[0067] In this embodiment of the present invention, after selecting a second satellite node for deploying the next VNF ​​from the optional satellite node set, the following steps are also included: Step S111, based on the formula Update the network parameters of the actor network in the actor-critic network model; based on the formula Update the network parameters of the critic network.

[0068] in, represents the network parameters of the actor network, represents the resource status of satellite node i in the current time slot t, Indicates that the VNF is deployed on satellite node i at the current time slot t, Representing the old strategy of the actor network , , The importance weights representing the relative differences between the new and old strategies of the actor network, represents the clipping hyperparameter, A new strategy for representing actor networks, , represents the advantage function calculated by TD error, represents the discount factor, represents the reward obtained by deploying VNF on satellite node m in time slot x, and t-u+1=C, represents the value function of the critic network in the actor-critic network model, Represents the network parameters of the critic network. The critic network updates its value function and returns the value to the actor network, guiding the update process of the actor network towards the global optimum.

[0069] In the actor-critic network, the policy refers to the rule or distribution for the agent to select actions at each time step. The old policy is the existing policy of the current network. It represents the reference rule when the network previously generated actions. It is used to measure the improvement of the new policy and ensure that the network update does not deviate from the optimization goal. The new policy is the optimized policy, which represents a better rule generated based on the current context trajectory (state) and reward signal. The new policy can better capture context information and improve the effect of action selection.

[0070] In summary, the embodiment of the present invention proposes a distributed point-by-point service function chain orchestration solution, which orchestrates service function chain requests by sequentially embedding a series of virtual network functions into a series of adjacent satellite nodes to reduce the computing power requirements of the centralized controller; and in the VNF deployment process, the embodiment of the present invention specifically uses the actor-critic network model with integrated decision transformer to generate and globally optimize the service function chain orchestration strategy, because the decision transformer can extract historical local network state features into the context trajectory, so the model can adaptively generate a more robust service function chain orchestration strategy using the trajectory, thereby effectively avoiding the problem of local optimality.

[0071] In order to evaluate the performance of the method provided by the embodiment of the present invention. Figures 5 to 7 The total reward value curves of different algorithms applied to different numbers of low-orbit satellites are shown respectively. Figures 5 to 7It can be seen that as the training progresses, the two artificial intelligence-based SFC orchestration algorithms (deep Q learning algorithm and ACDT algorithm) can obtain higher rewards. In contrast, the rewards of other algorithms fluctuate within a certain range. This shows that reinforcement learning can improve the SFC orchestration performance by interacting with the low-orbit satellite networking environment. Moreover, the results show that the optimal solution algorithm ranks first. This is because it greedily selects a series of optimal nodes to embed VNFs sequentially. The ACDT-based SFC orchestration algorithm proposed in the embodiment of the present invention is better than the other two baseline algorithms and can even approach the theoretical optimal solution. The first adaptation algorithm performs the worst due to its randomness. It is also noted that as the number of satellites increases, the average reward values ​​obtained by the four algorithms also increase. This is because more satellites mean that the network can provide more resources to support SFC orchestration. Moreover, the embedding VNF requests are more dispersed, thereby avoiding the single-point bottleneck problem. In addition, for the ACDT-based algorithm proposed in the embodiment of the present invention, its convergence time is also shortened. In the 13 low-orbit satellite network, it converges after about 4,000 rounds. In the 15 low-orbit satellite network, the time is reduced to about 2,000 rounds. In the 17 low-orbit satellite network, only about 1,200 rounds are needed. The deep Q learning algorithm always converges in about 3,000 rounds. This shows that the algorithm proposed in the embodiment of the present invention can make full use of the local information in the historical context trajectory to accelerate the convergence speed by benefiting from the context relevance capability.

[0072] Figures 8 to 10 The SFC scheduling success rates of different algorithms under different numbers of low-orbit satellites are shown. Figures 8 to 10 It can be seen that, similar to the convergence performance of the total reward value, the orchestration success rate also increases with the increase of the satellite scale. It can also be found that the gap between the optimal solution algorithm and the ACDT-based algorithm proposed in the present invention is gradually narrowing. Specifically, in 17 low-orbit satellite networks, the success rate performance difference between the optimal solution algorithm and the ACDT-based algorithm proposed in the present invention is only about 10%. This further proves that the algorithm proposed by the decision transformer structure can capture the temporal correlation of resources and local topology in the orchestration process, and use them to adaptively select stable nodes with sufficient resources to embed VNF requests.

[0073] Embodiment 2 An embodiment of the present invention also provides a service function chain orchestration device applicable to a low-orbit satellite network. The device is mainly used to execute the service function chain orchestration method applicable to a low-orbit satellite network provided in the above-mentioned embodiment one. The following is a specific introduction to the service function chain orchestration device applicable to a low-orbit satellite network provided in an embodiment of the present invention.

[0074] Fig.11A functional module diagram of a service function chain arrangement device suitable for a low-orbit satellite network provided by an embodiment of the present invention, such as Fig.11 As shown, the device mainly includes: a receiving and resetting module 11, a first calculating module 12, a deployment module 13, a determination module 14, a selection module 15, a second calculating module 16, and a return module 17, wherein: The receiving and resetting module 11 is used to receive a service function chain SFC request and reset the low-orbit satellite network environment; wherein the SFC request includes: a source base station, a destination base station and multiple virtual network functions VNFs arranged in a specified order.

[0075] The first calculation module 12 is used to calculate the scheduling direction unit vector of the SFC request according to the location coordinates of the source base station and the location coordinates of the destination base station.

[0076] The deployment module 13 is used to randomly select a satellite node within the communication range of the source base station, and deploy the first VNF ​​on the satellite node when it is determined that the satellite node meets the deployment conditions of the first VNF ​​in the SFC request.

[0077] The determination module 14 is used to determine a set of optional satellite nodes for deploying the next VNF ​​based on the orchestration direction unit vector, the position coordinates of the first satellite node that currently deploys the last VNF, and the position coordinates of the neighboring satellite nodes of the first satellite node.

[0078] The selection module 15 is used to process the C VNF trajectory points that have been deployed recently using the actor-critic network model of the integrated decision transformer to select a second satellite node for deploying the next VNF ​​from the set of optional satellite nodes; wherein each VNF trajectory point includes: the satellite node number of the deployed VNF, the resource status of the satellite node, and the reward obtained by deploying the VNF.

[0079] The second calculation module 16 is used to calculate the SFC orchestration duration when it is determined that the second satellite node meets the deployment conditions of the next VNF.

[0080] The return module 17 is used to return to the calling determination module when it is determined that the SFC orchestration duration is less than or equal to the preset duration threshold and the deployment of all VNFs in the SFC request has not been completed, until the deployment of all VNFs in the SFC request is completed.

[0081] The embodiment of the present invention provides a service function chain orchestration device suitable for low-orbit satellite networks. The device essentially implements a distributed point-by-point service function chain orchestration solution. It orchestrates service function chain SFC requests by sequentially embedding a series of virtual network functions VNFs into a series of adjacent satellite nodes. Therefore, the computing power requirements for the centralized controller are relatively low, and it is suitable for large-scale low-orbit satellite networks without stable centralized controllers. In the distributed deployment process of VNF, the optional satellite node set for deploying the next VNF ​​is first determined, and then the actor-critic network model with integrated decision transformer is used to process the most recently deployed C VNF trajectory points to select the second satellite node for deploying the next VNF ​​in the optional satellite node set. That is, the device can determine a more robust VNF ​​deployment decision based on global context information, reducing the local optimal problem that may be caused by relying only on the current state.

[0082] Optionally, the determination module 14 is specifically configured to: Based on the equal division principle and the position coordinates of the first satellite node, the spherical area covered by the communication of the first satellite node is divided into four quadrants to obtain four communication areas, and the coordinates of the center point of each communication area are determined.

[0083] Based on the center point coordinates of each communication area and the position coordinates of the first satellite node, a unit vector of each communication area is calculated.

[0084] The dot product of the unit vector of each communication area and the unit vector of the arrangement direction is calculated, and the four communication areas are sorted in descending order based on the dot product result.

[0085] When it is determined based on the position coordinates of the neighbor satellite nodes of the first satellite node that there is a neighbor satellite node in the first ranked target communication area, a selectable satellite node set is constructed based on all the neighbor satellite nodes in the target communication area.

[0086] Otherwise, the communication areas with lower ranking are selected in order until the set of optional satellite nodes is determined.

[0087] Optionally, the second calculation module 16 is specifically configured to: Using the formula Calculate the SFC scheduling duration; where, Indicates SFC request The SFC arrangement time, Indicates the time consumption of the current round of scheduling. Indicates the time consumption of historical round scheduling; , L represents the set of physical network links, Represents a collection of virtual network links. represents the single-hop transmission delay from satellite node u to satellite node v in time slot t, Indicates VNF virtual link Deployed on the physical network link uv, Indicates VNF virtual link Not deployed on the physical network link uv, represents the processing delay of satellite node i, indicates that the kth VNF is deployed at satellite node i, indicates that the kth VNF is not deployed at satellite node i, represents the total number of satellites in the low-orbit satellite network, Represents the set of all VNFs in the SFC request.

[0088] Optionally, after selecting a second satellite node for deploying a next VNF ​​from the set of optional satellite nodes, the device is further configured to: Based on the formula Update the network parameters of the actor network in the actor-critic network model; based on the formula Update the network parameters of the critic network; where, represents the network parameters of the actor network, represents the resource status of satellite node i in the current time slot t, Indicates that the VNF is deployed on satellite node i at the current time slot t, Representing the old strategy of the actor network , , The importance weights representing the relative differences between the new and old strategies of the actor network, represents the clipping hyperparameter, A new strategy for representing actor networks, , represents the advantage function calculated by TD error, represents the discount factor, represents the reward obtained by deploying VNF on satellite node m in time slot x, and t-u+1=C, represents the value function of the critic network in the actor-critic network model, represents the network parameters of the critic network.

[0089] Optionally, after selecting a second satellite node for deploying a next VNF ​​from the set of optional satellite nodes, the device is further configured to: When it is determined that the second satellite node does not meet the deployment conditions of the next VNF, all deployed VNFs in the low-orbit satellite network are released, and the process returns to step S106, and the SFC orchestration duration is updated.

[0090] Optionally, after calculating the SFC scheduling duration, the device is further used to: When it is determined that the SFC scheduling duration is greater than the preset duration threshold, it is determined that the SFC request scheduling fails.

[0091] Embodiment 3 See also Fig.12 An embodiment of the present invention provides an electronic device, which includes: a processor 60, a memory 61, a bus 62 and a communication interface 63, the processor 60, the communication interface 63 and the memory 61 are connected through the bus 62; the processor 60 is used to execute an executable module stored in the memory 61, such as a computer program.

[0092] The memory 61 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 63 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used.

[0093] The bus 62 may be an ISA bus, a PCI bus, or an EISA bus. The bus may be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, Fig.12 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0094] Among them, the memory 61 is used to store programs, and the processor 60 executes the program after receiving the execution instruction. The method executed by the device defined by the process disclosed in any embodiment of the above-mentioned embodiment of the present invention can be applied to the processor 60 or implemented by the processor 60.

[0095] The processor 60 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 60. The above processor 60 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiments of the present invention can be directly embodied as a hardware decoding processor to be executed, or the hardware and software modules in the decoding processor can be executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 61, and the processor 60 reads the information in the memory 61 and completes the steps of the above method in combination with its hardware.

[0096] A computer program product of a service function chain orchestration method and device applicable to a low-orbit satellite network provided in an embodiment of the present invention includes a computer-readable storage medium storing a non-volatile program code executable by a processor. The instructions included in the program code can be used to execute the method in the previous method embodiment. For specific implementation, please refer to the method embodiment, which will not be repeated here.

[0097] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0098] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0099] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0100] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0101] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0102] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A service function chain arrangement method applicable to a low-orbit satellite network, characterized in that: include: Step S102, receiving a service function chain SFC request and resetting the low-orbit satellite network environment; wherein the SFC request includes: a source base station, a destination base station, and a plurality of virtual network functions VNFs arranged in a specified order; Step S104, calculating the arrangement direction unit vector of the SFC request according to the location coordinates of the source base station and the location coordinates of the destination base station; Step S106, randomly selecting a satellite node within the communication range of the source base station, and deploying the first VNF ​​on the satellite node if it is determined that the satellite node meets the deployment condition of the first VNF ​​in the SFC request; Step S108, determining a set of optional satellite nodes for deploying the next VNF ​​based on the orchestration direction unit vector, the position coordinates of the first satellite node that currently deploys the last VNF, and the position coordinates of the neighboring satellite nodes of the first satellite node; Step S110, using the actor-critic network model with integrated decision transformer to process the most recently deployed C VNF trajectory points, so as to select a second satellite node for deploying the next VNF ​​from the optional satellite node set; wherein each of the VNF trajectory points includes: the satellite node number of the deployed VNF, the resource status of the satellite node, and the reward obtained by deploying the VNF; Step S112, when it is determined that the second satellite node meets the deployment condition of the next VNF, calculate the SFC orchestration duration; Step S114, when it is determined that the SFC orchestration duration is less than or equal to the preset duration threshold and the deployment of all VNFs in the SFC request has not been completed, return to step S108 until the deployment of all VNFs in the SFC request is completed.

2. The service function chain arrangement method applicable to a low-orbit satellite network according to claim 1, characterized in that: Determining a set of optional satellite nodes for deploying a next VNF ​​based on the orchestration direction unit vector, the position coordinates of the first satellite node that currently deploys the last VNF, and the position coordinates of the neighboring satellite nodes of the first satellite node, including: Based on the equal division principle and the position coordinates of the first satellite node, the spherical area covered by the communication of the first satellite node is divided into four quadrants to obtain four communication areas, and the coordinates of the center point of each of the communication areas are determined; Calculate the unit vector of each communication area based on the center point coordinates of each communication area and the position coordinates of the first satellite node; Calculating the dot product of the unit vector of each communication area and the arrangement direction unit vector, and sorting the four communication areas in descending order based on the dot product result; In a case where it is determined based on the position coordinates of the neighbor satellite nodes of the first satellite node that there is a neighbor satellite node in the first-ranked target communication area, constructing the selectable satellite node set based on all the neighbor satellite nodes in the target communication area; Otherwise, the communication areas ranked later are selected in order until the selectable satellite node set is determined.

3. The service function chain arrangement method applicable to a low-orbit satellite network according to claim 1, characterized in that: Calculate the SFC scheduling time, including: Using the formula Calculate the SFC scheduling duration; wherein, Indicates SFC request The SFC arrangement time, Indicates the time consumption of the current round of scheduling. Indicates the time consumption of historical round scheduling; , L represents the set of physical network links, Represents a collection of virtual network links. represents the single-hop transmission delay from satellite node u to satellite node v in time slot t, Indicates VNF virtual link Deployed on the physical network link uv, Indicates VNF virtual link Not deployed on the physical network link uv, represents the processing delay of satellite node i, indicates that the kth VNF is deployed at satellite node i, indicates that the kth VNF is not deployed at satellite node i, represents the total number of satellites in the low-orbit satellite network, Represents the set of all VNFs in the SFC request.

4. The service function chain arrangement method applicable to a low-orbit satellite network according to claim 1, characterized in that: After selecting a second satellite node for deploying the next VNF ​​from the set of optional satellite nodes, the method further includes: Step S111, based on the formula Update the network parameters of the actor network in the actor-critic network model; based on the formula Updating network parameters of the critic network; in, represents the network parameters of the actor network, represents the resource status of satellite node i in the current time slot t, Indicates that the VNF is deployed on satellite node i at the current time slot t, Represents the old policy of the actor network , , The importance weights representing the relative differences between the new and old strategies of the actor network, represents the clipping hyperparameter, A new strategy for representing actor networks, , represents the advantage function calculated by TD error, represents the discount factor, represents the reward obtained by deploying VNF on satellite node m in time slot x, and t-u+1=C, represents the value function of the critic network in the actor-critic network model, represents the network parameters of the critic network.

5. The service function chain arrangement method applicable to a low-orbit satellite network according to claim 1, characterized in that: After selecting a second satellite node for deploying the next VNF ​​from the set of optional satellite nodes, the method further includes: Step S113, when it is determined that the second satellite node does not meet the deployment conditions of the next VNF, release all deployed VNFs in the low-orbit satellite network, return to step S106, and update the SFC orchestration duration.

6. The service function chain arrangement method applicable to a low-orbit satellite network according to claim 1, characterized in that: After calculating the SFC scheduling duration, it also includes: Step S115: When it is determined that the SFC scheduling duration is greater than the preset duration threshold, it is determined that the SFC scheduling request fails.

7. A service function chain arrangement device suitable for a low-orbit satellite network, characterized in that: include: A receiving and resetting module, configured to receive a service function chain (SFC) request and reset a low-orbit satellite network environment; wherein the SFC request includes: a source base station, a destination base station, and a plurality of virtual network functions (VNFs) arranged in a specified order; A first calculation module, configured to calculate an arrangement direction unit vector of the SFC request according to the location coordinates of the source base station and the location coordinates of the destination base station; A deployment module, configured to randomly select a satellite node within the communication range of the source base station, and deploy the first VNF ​​on the satellite node if it is determined that the satellite node meets the deployment condition of the first VNF ​​in the SFC request; A determination module, configured to determine a set of optional satellite nodes for deploying a next VNF ​​based on the orchestration direction unit vector, the position coordinates of the first satellite node that currently deploys the last VNF, and the position coordinates of the neighboring satellite nodes of the first satellite node; A selection module is used to process the C most recently deployed VNF trajectory points using an actor-critic network model with an integrated decision transformer to select a second satellite node for deploying the next VNF ​​from the set of optional satellite nodes; wherein each of the VNF trajectory points includes: a satellite node number for deploying the VNF, a resource status of the satellite node, and a reward obtained by deploying the VNF; A second calculation module is used to calculate the SFC orchestration duration when it is determined that the second satellite node meets the deployment condition of the next VNF; The return module is used to return to the calling determination module when it is determined that the SFC orchestration duration is less than or equal to a preset duration threshold and the deployment of all VNFs in the SFC request has not been completed, until the deployment of all VNFs in the SFC request is completed.

8. The service function chain arrangement device applicable to a low-orbit satellite network according to claim 7, characterized in that: The determination module is specifically used for: Based on the equal division principle and the position coordinates of the first satellite node, the spherical area covered by the communication of the first satellite node is divided into four quadrants to obtain four communication areas, and the coordinates of the center point of each of the communication areas are determined; Calculate the unit vector of each communication area based on the center point coordinates of each communication area and the position coordinates of the first satellite node; Calculating the dot product of the unit vector of each communication area and the arrangement direction unit vector, and sorting the four communication areas in descending order based on the dot product result; In a case where it is determined based on the position coordinates of the neighbor satellite nodes of the first satellite node that there is a neighbor satellite node in the first-ranked target communication area, constructing the selectable satellite node set based on all the neighbor satellite nodes in the target communication area; Otherwise, the communication areas ranked later are selected in order until the selectable satellite node set is determined.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, wherein: When the processor executes the computer program, the service function chain orchestration method applicable to a low-orbit satellite network described in any one of claims 1 to 6 is implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by the processor, the service function chain orchestration method applicable to a low-orbit satellite network as described in any one of claims 1 to 6 is implemented.

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