Inter-satellite routing method and device for low-Earth orbit constellation networks

Abstract

This invention relates to the field of satellite communication technology, and particularly to an inter-satellite routing method and apparatus for low-Earth orbit (LEO) constellation networks. The method includes: autonomously learning and calculating routes within the constellation network based on the OSPF and / or BGP protocols running in the constellation network, and storing a routing table; the routing table includes at least the north-south vertical hop count and the east-west horizontal hop count from the current satellite node to every other node in the constellation network; in response to a route forwarding service to the destination satellite node, determining the hop count based on the routing table; determining whether a forwarding rectangle can be formed based on the hop count; wherein the current satellite node and the destination satellite node are the two opposite vertices of the forwarding rectangle, and the north-south vertical hop count and the east-west horizontal hop count are the two side lengths of the forwarding rectangle; if a forwarding rectangle can be formed, determining the output interface for route forwarding based on the area of ​​the forwarding rectangle and the routing table. This solution can efficiently and accurately achieve inter-satellite routing in constellation networks.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and in particular to an inter-satellite routing method and apparatus for a low-Earth orbit constellation network. Background Technology

[0002] Low Earth orbit (LEO) satellite constellations, with their wide coverage and all-weather operation, have become the most effective solution to fill the coverage gaps of terrestrial networks and are an important component of the future integrated space-air-ground-sea network. Satellite internet is generally divided into three parts: constellation network, terrestrial network, and satellite terminals. Among them, the constellation network mainly carries inter-satellite interconnection services, realizing an integrated space-air-ground internet network.

[0003] Because low-Earth orbit (LEO) constellations move at high speeds relative to Earth, averaging 7–8 km / s and completing one orbit in approximately 100 minutes, the links between satellites are highly unstable, and the topology is constantly changing. This poses a significant challenge to inter-satellite routing methods. Currently, typical inter-satellite routing methods mainly include the virtual topology method and the virtual node method.

[0004] The core idea of ​​the virtual topology method is to use the constellation's operational patterns (i.e., ephemeris) to divide time slots based on the constellation's topological changes (within a time slot, the constellation's topology remains unchanged). For each time slot, the connection relationships of all satellites can be known based on the ephemeris, so its topology can be obtained in advance. Therefore, the route for each node can be calculated in advance on the ground for each time slot and uploaded to each node. At the beginning of each time slot, each satellite node downloads the pre-calculated routing table and forwards according to this routing table within a time slot.

[0005] The core idea of ​​the virtual node method is to divide a geographical area into several cells, called virtual nodes. Each virtual node is assigned a logical address and establishes a mapping relationship with the satellite it is responsible for covering, sharing the logical address with the satellite. When a satellite no longer covers a cell, the virtual node is mapped to the next covering satellite, which inherits the logical address and network status (including routing tables, channel allocation, etc.) of the previous satellite. Thus, a static virtual network is constructed through the dynamic mapping between virtual nodes and satellites.

[0006] However, for the virtual topology method, pre-calculating the route for each satellite node in the constellation network within each time slice results in extremely high storage requirements when the number of satellite nodes in the constellation network is large. Furthermore, due to topological changes in the constellation network, there is a problem where pre-calculated time-slice routes cannot be forwarded. For the virtual node method, frequent calculations of the coverage relationship between satellites and ground areas are required, and when virtual nodes switch between different orbital planes, the uncertainty of the polar orbit constellation gap positions increases, meaning the virtual network topology is not completely static. Moreover, due to the Earth's rotation, after a long period of mapping establishment, the satellite orbital plane will deviate significantly from the original coverage cell, making it impossible to complete virtual node switching within the orbital plane.

[0007] Given the shortcomings of the two inter-satellite routing methods mentioned above, there is an urgent need to provide a new inter-satellite routing method that can efficiently and accurately realize inter-satellite routing in constellation networks. Summary of the Invention

[0008] This invention provides an inter-satellite routing method and apparatus for low-Earth orbit constellation networks, which can efficiently and accurately realize inter-satellite routing in constellation networks.

[0009] In a first aspect, embodiments of the present invention provide an inter-satellite routing method for a low-Earth orbit (LEO) constellation network, applicable to any satellite node in the LEO constellation network, the method comprising:

[0010] Based on the open shortest path first protocol and / or border gateway protocol running in the constellation network, the system autonomously learns and calculates routes for the constellation network and stores a routing table of the current network topology; the routing table includes at least the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to every other node in the constellation network.

[0011] In response to the routing forwarding service to the destination satellite node, the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to the destination satellite node are determined based on the routing table;

[0012] Based on the target's north-south vertical hop count and the target's east-west horizontal hop count, it is determined whether a forwarding rectangle can be formed in the current network topology; wherein, the current satellite node and the target satellite node are the two opposite vertices of the forwarding rectangle, and the target's north-south vertical hop count and the target's east-west horizontal hop count are the two side lengths of the forwarding rectangle, respectively;

[0013] If the forwarding rectangle can be formed, the output interface for route forwarding is determined based on the area of ​​the forwarding rectangle and the routing table.

[0014] Secondly, embodiments of the present invention also provide an inter-satellite routing device for a low-Earth orbit (LEO) constellation network, applicable to any satellite node in the LEO constellation network, the device comprising:

[0015] The routing calculation unit is used to autonomously learn and calculate routes in the constellation network based on the Open Shortest Path First (OSB) protocol and / or Border Gateway Protocol (BGLP) running in the constellation network, and to store a routing table of the current network topology; the routing table includes at least the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to every other node in the constellation network.

[0016] The hop count determination unit is used to determine the target north-south vertical hop count and the target east-west horizontal hop count from the current satellite node to the target satellite node based on the routing table in response to the routing forwarding service to the target satellite node.

[0017] The forwarding rectangle determination unit is used to determine whether a forwarding rectangle can be formed in the current network topology based on the target's north-south vertical hop count and the target's east-west horizontal hop count; wherein, the current satellite node and the target satellite node are the two opposite vertices of the forwarding rectangle, and the target's north-south vertical hop count and the target's east-west horizontal hop count are the two side lengths of the forwarding rectangle, respectively;

[0018] The output interface determination unit is used to determine the output interface for route forwarding based on the area of ​​the forwarding rectangle and the routing table when the forwarding rectangle can be formed.

[0019] Thirdly, embodiments of the present invention also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.

[0020] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.

[0021] This invention provides an inter-satellite routing method and apparatus for a low-Earth orbit (LEO) constellation network. By running an Open Shortest Path First (OSB) protocol and / or a Border Gateway Protocol (BGP) within the constellation network, communication can be established between satellite nodes. Each satellite node can autonomously learn and calculate routes within the constellation network. Compared to passively receiving pre-calculated routing tables from ground stations, the results obtained through autonomous route learning and calculation are more accurate. Furthermore, by extending the routing table with two parameters—the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction—the optimal routing forwarding path is selected based on these parameters, thus determining the output interface for routing forwarding at the current satellite node. Therefore, this solution not only learns and calculates the constellation network's routing table more accurately but also selects the optimal routing forwarding path, efficiently completing routing forwarding services, thereby realizing inter-satellite routing within the constellation network. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of an inter-satellite routing method for a low-Earth orbit constellation network according to an embodiment of the present invention;

[0024] Figure 2 This is a network topology diagram of a constellation network provided in an embodiment of the present invention;

[0025] Figure 3 This is a network topology diagram of another constellation network provided in one embodiment of the present invention;

[0026] Figure 4 This is a network topology diagram of another constellation network provided in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of a routing and forwarding path provided in an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of another routing and forwarding path provided by an embodiment of the present invention;

[0029] Figure 7 This is a schematic diagram of another routing and forwarding path provided in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of another routing and forwarding path provided in an embodiment of the present invention;

[0031] Figure 9 This is a hardware architecture diagram of an electronic device provided in an embodiment of the present invention;

[0032] Figure 10 This is a structural diagram of an inter-satellite routing device for a low-Earth orbit constellation network provided in an embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] As mentioned earlier, in existing inter-satellite routing methods, the routing tables in satellite nodes are passively received, and routing can be performed simply according to these passively received tables. Furthermore, existing inter-satellite routing methods suffer from problems such as large storage requirements and inaccurate routing due to topology changes.

[0035] The inventive concept of this invention lies in enabling satellite nodes in a constellation network to autonomously learn and calculate routes within the constellation network, thereby improving the accuracy of the learning and calculation results. This autonomous learning and calculation can be achieved based on the Open Shortest Path First (OSPF) protocol and / or the Border Gateway Protocol (BGP). OSPF and / or BGP protocols can discover and obtain relevant information about satellite nodes on the same and different orbits, thus determining the network topology of the constellation network and extending the parameters to include the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction, thereby enabling the selection of the optimal routing path.

[0036] The specific implementation of the above concept is described below.

[0037] Please refer to Figure 1 This invention provides an inter-satellite routing method for a low-Earth orbit (LEO) constellation network, applicable to any satellite node in the LEO constellation network. The method includes:

[0038] Step 100: Based on the Open Shortest Path First (OSB) protocol and / or Border Gateway Protocol (BGLP) running in the constellation network, autonomously perform route learning and calculation for the constellation network, and store a routing table of the current network topology; the routing table includes at least the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to every other node in the constellation network;

[0039] Step 102: In response to the routing forwarding service to the destination satellite node, determine the target north-south vertical hop count and the target east-west horizontal hop count from the current satellite node to the destination satellite node based on the routing table;

[0040] Step 104: Determine whether a forwarding rectangle can be formed in the current network topology based on the target's north-south vertical hop count and the target's east-west horizontal hop count; wherein, the current satellite node and the target satellite node are the two opposite vertices of the forwarding rectangle, and the target's north-south vertical hop count and the target's east-west horizontal hop count are the two side lengths of the forwarding rectangle, respectively;

[0041] Step 106: If the forwarding rectangle can be formed, then determine the output interface for route forwarding based on the area of ​​the forwarding rectangle and the routing table.

[0042] In this embodiment of the invention, by running an Open Shortest Path First (OSF) protocol and / or a Border Gateway Protocol (BGP) within the constellation network, communication can be established between multiple satellite nodes. Each satellite node can autonomously learn and calculate routes within the constellation network. Compared to passively receiving routing tables pre-calculated by ground stations, the results obtained through autonomous route learning and calculation are more accurate. Furthermore, by extending the routing table with two parameters—the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction—the optimal routing forwarding path is selected based on these parameters, thus determining the output interface for routing forwarding at the current satellite node. Therefore, this scheme not only learns and calculates the constellation network's routing table more accurately but also selects the optimal routing forwarding path, efficiently completing routing forwarding services, thereby realizing inter-satellite routing within the constellation network.

[0043] The following description Figure 1 The execution method for each step is shown.

[0044] First, for step 100, based on the Open Shortest Path First (OSB) protocol and / or Border Gateway Protocol (BGLP) running in the constellation network, the system autonomously learns and calculates routes for the constellation network and stores a routing table of the current network topology; the routing table includes at least the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to every other node in the constellation network.

[0045] In this embodiment of the invention, a self-learning and computational approach is used for route learning and computation in the constellation network, which may specifically include the following steps 1000-1004:

[0046] 1000: Identify adjacent satellite nodes that are connected to the current satellite node in the same orbit and across orbits, respectively;

[0047] 1002: Send the current satellite node's route to each neighboring satellite node, and receive the route forwarded by each neighboring satellite node;

[0048] 1004: Calculate the north-south vertical hop count and east-west horizontal hop count for each other satellite node in the constellation network of the current satellite node based on the received route, in order to update the routing table of the current satellite node.

[0049] The protocols running in a constellation network can be OSPF (running across the entire network), BGP (running across the entire network), or OSPF (running on the same orbit) and BGP (running on different orbits). These protocols are used to discover neighboring satellite nodes connected to the current satellite node in the north-south vertical direction within the same orbit and in the east-west direction across different orbits.

[0050] Preferably, the OSPF protocol can run within the same orbit, and the BGP protocol can run between orbits. Hello packets are used to discover neighboring satellite nodes within and across orbits, thereby obtaining the location information (longitude and latitude) of neighboring satellite nodes. By establishing communication links with neighboring satellite nodes, a topology relationship between the current satellite node and its neighbors is formed. This topology relationship needs to be communicated to every satellite node in the constellation network. Therefore, by forwarding the current satellite node's route to every neighboring satellite node, the neighboring satellite nodes, after learning about the topology relationship based on this route, will also forward their updated routes to other satellite nodes. This ensures that every satellite node in the constellation network can know the topology relationship between all satellite nodes in the constellation network, and can then learn and calculate the constellation network's routing table based on these topology relationships.

[0051] In this embodiment of the invention, the following two parameters are defined:

[0052] 1. Number of jumps in the north-south vertical direction (V-hop)

[0053] V-hop represents the number of hops required for the route from the current satellite node to the destination satellite node in the vertical direction (i.e., north-south). The sign of V-hop can be defined to represent the relationship between the routing direction and the satellite's motion direction. In one implementation, V-hop can be defined as positive when the direction from the destination satellite node to the current satellite node is consistent with the satellite's motion direction, and negative otherwise. Please refer to [reference needed]. Figure 2 For target satellite node 2, the V-hop on satellite node 1 is +3, and the V-hop on satellite node 3 is -1.

[0054] 2. Number of jumps in the east-west horizontal direction (H-hop)

[0055] H-hop represents the number of hops required for the relay from the current satellite node to the destination satellite node in the horizontal direction (i.e., east-west direction). Similarly, we can define H-hop as positive if the destination satellite node is east of the current satellite node, and negative otherwise. Continuing with... Figure 2 For example, for the target satellite node 3, the H-hop is +1 on satellite node 1 and -3 on satellite node 2.

[0056] These two parameters carry V-hop information through extended OSPF attributes and H-hop information through extended BGP attributes. When forwarding topology relationships, these two parameters are communicated to other satellite nodes through OSPF and BGP attributes.

[0057] Therefore, when calculating the routing table in each satellite node, the routing table also needs to include the north-south vertical hop count and the east-west horizontal hop count from the current satellite node to every other node in the constellation network. This allows the satellite node to determine the optimal routing path based on these two hop counts.

[0058] Furthermore, since traditional OSPF and BGP protocols are applied to terrestrial networks, where the positions of each node are fixed, while for constellation networks, satellite nodes are in motion and the link relationships between satellite nodes can change, in one embodiment of the present invention, to ensure the accuracy of the constellation network topology, it may further include: according to preset route update conditions, when it is determined that the route update conditions are met, the autonomous constellation network route learning and calculation is performed again to update the stored routing table.

[0059] The route update conditions may include: setting a time interval, changes in the link status between satellite nodes and ground stations (e.g., power supply UP, power supply DOWN), and changes in the link status between satellite nodes (e.g., link UP, link DOWN).

[0060] Because low-Earth orbit satellite nodes pass through the two polar regions (North and South Poles) during their orbits around the Earth, the network topology of the constellation network changes when they pass through the poles. Therefore, a hello handshake needs to be performed at set intervals to promptly determine the link changes between satellite nodes. For example, if the set interval is 5 seconds, a hello handshake is performed with the adjacent satellite node every 5 seconds. If no feedback is received from the adjacent satellite node after a set number of hello handshakes (e.g., 3 times), it is determined that the link with that adjacent satellite node has been broken.

[0061] When responding to routing forwarding services, the traffic resolved by the base station needs to be forwarded to the ground station through the landing satellite (the satellite node that establishes a GSL link with the ground station). Therefore, if the landing satellite changes, the routing table needs to be updated to ensure that the routing forwarding service can proceed normally.

[0062] As can be seen, in this embodiment of the invention, by improving traditional dynamic routing protocols (OSPF and BGP), inter-satellite routing in a constellation network is achieved. This allows the routing learning and calculation of the entire constellation network to be performed autonomously by the routing components in the satellite nodes (in traditional schemes, the routing components in the satellite nodes do not participate in calculations but passively receive routing tables). This enables efficient and rapid route updates, ensuring reliable transmission of inter-satellite services. Furthermore, in a giant constellation network, the CPU / memory requirements of this dynamic routing protocol do not increase linearly, avoiding increasing the resource burden on the onboard routing system and avoiding the large storage requirements of the virtual topology method and the complexity requirements of the virtual node method.

[0063] Then, steps 102, 104 and 106 will be explained simultaneously.

[0064] When there is a routing forwarding service to the destination satellite node, it is necessary to be able to respond to the routing forwarding service quickly and efficiently, and the forwarding rules need to meet the requirements of 4-satellite link networking and 3-satellite link networking scenarios.

[0065] For 4-link networking scenarios, please refer to Figure 3 Each satellite node has four links: one north-south link within the same orbit and one east-west link across orbits, ultimately forming a logical grid-like network. The north-south links are evenly distributed, while the east-west links have the longest distance and the greatest latency at the equator. The closer to the poles, the closer the distance and the smaller the latency.

[0066] For 3-link networking scenarios, please refer to Figure 4 Each satellite node has only 3 links: one link in the north-south direction within the same orbit, and only one link in the east-west direction across different orbits. These links are staggered in the east and west directions to ensure a uniform distribution of network links.

[0067] To meet the requirements of the two inter-satellite link networking scenarios mentioned above, this embodiment of the invention proposes the concept of a "forwarding rectangle," where the current satellite node and the target satellite node are the two opposite vertices of the forwarding rectangle, and the target's north-south vertical hop count and east-west horizontal hop count are the two side lengths of the forwarding rectangle, respectively. Please refer to [reference needed]. Figure 3 , Figure 4 The forwarding rectangle area is defined within the given area. The optimal routing forwarding path is selected based on this forwarding rectangle area.

[0068] Therefore, when determining whether a forwarding rectangle can be formed in the current network topology based on the target's north-south vertical hop count and the target's east-west horizontal hop count, the following can be included: if both the target's north-south vertical hop count and the target's east-west horizontal hop count are not equal to 0, then it is determined that a forwarding rectangle can be formed in the current network topology; otherwise, it is determined that a forwarding rectangle cannot be formed in the current network topology.

[0069] In one embodiment of the present invention, routing and forwarding can be performed using at least the following two forwarding rules:

[0070] The first forwarding rule: the shortest path rule;

[0071] The second forwarding rule: load sharing rule.

[0072] The two forwarding rules mentioned above will be explained below.

[0073] For the first forwarding rule, determining the output interface for route forwarding based on the area of ​​the forwarding rectangle and the routing table may include the following steps A1-A2:

[0074] A1: Determine the latitude relationship between the current satellite node and the target satellite node, and determine the order of cross-orbit forwarding and intra-orbit forwarding based on the latitude relationship;

[0075] A2: According to the forwarding direction that comes first in the order, determine whether there is an output interface in the routing table that corresponds to the forwarding direction; if there is, determine the output interface that corresponds to the forwarding direction as the output interface for routing forwarding; if there is not, reverse the order and continue to execute step A2 based on the adjusted order.

[0076] In step A1, since the satellite nodes in the constellation network are evenly distributed along the north-south links, the distances along the north-south links are the same when the number of hops in the north-south vertical direction is the same. However, along the east-west links, the distance gradually decreases from the equator to the poles and gradually increases from the poles to the equator. Therefore, when the number of hops in the east-west horizontal direction is the same, the distance along the east-west links is smaller the closer to the poles. Thus, to ensure that the routing forwarding path is the shortest path, the order of cross-orbit forwarding and intra-orbit forwarding can be determined based on the latitude relationship between the current satellite node and the destination satellite node. Specifically:

[0077] The routing table also includes the latitude of each satellite node. Based on the routing table, the latitude of the current satellite node and the destination satellite node are determined. If the latitude of the current satellite node is greater than the latitude of the destination satellite node, the order is cross-track forwarding first, then same-track forwarding; otherwise, the order is same-track forwarding first, then cross-track forwarding. Furthermore, according to the above setting for the sign of the hop count, if the H-hop is positive, eastward forwarding occurs; otherwise, westward forwarding occurs.

[0078] In step A2, since the constellation network includes both 4-link and 3-link networking scenarios, after determining the order of cross-track forwarding and intra-track forwarding, it is necessary to determine whether the output interface for the preceding forwarding direction exists in the routing table. This is because for a 3-link networking scenario, there may only be one output interface within the forwarding rectangle. If this single output interface (the link corresponding to this output interface is located within the forwarding rectangle) corresponds to the forwarding direction, then this output interface is directly determined as the output interface for routing forwarding; otherwise, after reversing the order, the preceding forwarding direction corresponds to the single output interface, and this single output interface is determined as the output interface for routing forwarding.

[0079] by Figure 5 Taking the routing path shown as an example, when determining the route to the destination satellite node 2 for the current satellite node 1: According to the routing table, V-hop = +2, H-hop = +4. The latitude of the current satellite node 1 is higher than that of the destination satellite node 2, so a cross-orbit forwarding is performed first. After forwarding to the orbit where the destination satellite node 2 is located, it is forwarded on the same orbit, and finally the packet reaches the destination satellite node 2. Figure 5 The path shown; when determining the route to the destination satellite node 3 for the current satellite node 1: according to the routing table, V-hop = +4, H-hop = +4. The latitude of the current satellite node 1 is lower than that of the destination satellite node 3, so it first performs same-track forwarding, forwarding to the orbit where the destination satellite node 3 is located, and then performs cross-track forwarding. Finally, the message reaches the destination satellite node 3. Figure 5 The path shown.

[0080] For the second forwarding rule, the output interface for route forwarding based on the area of ​​the forwarding rectangle and the routing table can include: determining the target output interface in the forwarding path corresponding to the multiple output interfaces of the routing table, where the forwarding path is located within the area of ​​the forwarding rectangle; determining all the target output interfaces as output interfaces for route forwarding; and when there are multiple target output interfaces, performing route forwarding through load balancing.

[0081] In this embodiment of the invention, after the route is forwarded to each satellite node, the current satellite node can form a forwarding rectangle area based on the V-hop and H-hop of the destination satellite node, and there are multiple paths within the forwarding rectangle area, which are all relatively optimal routing forwarding paths.

[0082] In another embodiment of the present invention, before determining the target output interface within the area of ​​the forwarding rectangle in the forwarding paths corresponding to the multiple output interfaces of the routing table, it can be further determined whether the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction of the target are both less than a set hop count threshold. If so, a load-sharing rule is used to determine the output interface for route forwarding. If the ground stations are relatively evenly distributed, the values ​​of V-hop and H-hop will be relatively small, for example, if the set hop count threshold is 4. In this case, selecting a load-sharing rule to determine the route forwarding path can ensure that the difference in forwarding latency between different paths is small.

[0083] Based on this, a load-sharing path can be formed by using all output interfaces within the forwarding rectangle area of ​​each satellite node. This satisfies latency requirements while significantly improving the efficiency of all links. For the underlying principle, please refer to [link to documentation / reference]. Figure 6 Specifically, starting from the current satellite node 1, traffic load balancing is performed in both the east-west and north-south directions. Other satellite nodes within the forwarding rectangle (except those on the same orbit as the destination satellite node 2, and those at the same latitude as the destination satellite node 2) all execute the same forwarding strategy as the current satellite node 1, performing load balancing. Figure 6 Other satellite nodes in China Figure 6 The arrows in the diagram indicate forwarding. Using this second forwarding rule, traffic from the current satellite node 1 to the destination satellite node 2 will be load-balanced across the links within the forwarding rectangle area, ensuring even distribution of traffic across the relevant links and significantly improving link efficiency.

[0084] The two forwarding rules mentioned above can be determined through configuration.

[0085] It should be noted that when a forwarding rectangle cannot be formed, if the current satellite node and the destination satellite node are on the same track, then forwarding on the same track will be prioritized based on the two forwarding rules mentioned above. If the current satellite node and the destination satellite node are on different tracks, then forwarding on different tracks will be prioritized based on the two forwarding rules mentioned above.

[0086] Furthermore, regardless of which forwarding rule is used, the traffic status and / or link status of the output interface during the routing forwarding process can be considered to determine whether to re-determine the output interface based on the traffic status and / or link status of the output interface.

[0087] The following explains how to consider traffic status and link status separately.

[0088] 1. Traffic Status

[0089] Constellation networks, limited by physical transmission conditions, lack the massive bandwidth resources of terrestrial fiber optic networks. They typically use microwave or laser transmission, characterized by bandwidth limitations and high cost per bit. Therefore, in certain localized areas, network congestion can easily occur due to bandwidth constraints. In such cases, appropriate mechanisms are needed to avoid congestion and achieve reasonable traffic scheduling.

[0090] Please refer to Figure 7 Within the forwarding rectangle area, there are all selectable routing forwarding paths. Forwarding is first performed based on the delay-first path. When forwarding at each satellite node, the traffic status on the output interface of the forwarding is judged. When traffic congestion occurs, traffic bypass forwarding logic is executed on that satellite node.

[0091] 2. Link Status

[0092] Satellite nodes in a constellation network are in high-speed motion, making the links between them unstable. Furthermore, constellation networks experience regular link interruptions (e.g., solar outages, passing through polar regions). In these situations, constellation networks require rapid service protection and failover capabilities to ensure service quality. Another characteristic of constellation networks is their mesh-like link structure, resulting in a large number of path options. For shortest path solutions, after selecting the optimal path, the next best path forms a protection path. When the optimal path fails, traffic can be quickly switched to the next best path. For load-sharing solutions, multiple paths are used as equivalent paths to forward traffic; if any one path fails, traffic is automatically distributed to other paths.

[0093] Please refer to Figure 8 Within the forwarding rectangle formed by the current satellite node 1 and the destination satellite node 2, all forwarding paths are selectable. Forwarding is first performed according to the delay-priority path. BFD runs on the links that need protection. When a fault occurs in the forwarding direction or a downstream node, BFD will quickly detect it and trigger local protection switching, that is, execute traffic bypass forwarding logic on the satellite node. BFD can quickly detect faults (10ms) and achieve protection switching at the 50ms level.

[0094] In this embodiment of the invention, an extension is made at the protocol level, providing a rectangular forwarding area algorithm based on H-hop and V-hop at the routing and forwarding path algorithm level, breaking through the bottleneck of traditional routing protocols in inter-satellite routing applications. This is mainly reflected in the following aspects:

[0095] 1. Simplicity

[0096] Each satellite node only needs to run 2 OSPF neighbors and 2 BGP neighbors, with the number of routing entries on the order of M+N, where M is the number of orbits and N is the number of satellites in each orbit. Therefore, the consumption of CPU and memory is minimal and will not put any pressure on the satellite routing system.

[0097] 2. Robustness

[0098] Since each satellite node ultimately calculates a rectangular forwarding area with numerous alternative paths, any failure on the current forwarding path can quickly switch services to other backup paths, unless a forwarding island is created due to the failure of all relevant paths. Furthermore, in cases of traffic congestion, traffic can be redirected to other available paths.

[0099] 3. Convergence

[0100] Since the entire constellation network runs the OSPF / BGP protocol, any network topology change can be promptly converged according to the routing protocol. Because each satellite node has very few routing protocol neighbors (maximum 4), the speed of route refresh and convergence is also very fast (seconds). Therefore, the entire algorithm has very fast convergence to changes in network topology.

[0101] 4. Flexibility

[0102] This invention extends the basic OSPF / BGP protocol, thus fully inheriting the characteristics of terrestrial routing networks in terms of flexibility. Regardless of any predictable or unpredictable changes in the network, the routing protocol will update the H-hop and V-hop of the entire network according to the pre-defined rules, thereby ensuring that each node can forward traffic according to the forwarding rectangle algorithm. This makes the spaceborne routing system using this embodiment highly flexible in adapting to various network adjustments and changes.

[0103] like Figure 9 , Figure 10 As shown, this embodiment of the invention provides an inter-satellite routing device for a low-Earth orbit constellation network. The device embodiment can be implemented through software, hardware, or a combination of both. From a hardware perspective, as... Figure 9 The diagram shown is a hardware architecture diagram of an electronic device housing an inter-satellite routing device in a low-Earth orbit constellation network according to an embodiment of the present invention. (Except for...) Figure 9 In addition to the processor, memory, network interface, and non-volatile memory shown, the electronic device in the embodiment may also include other hardware, such as a forwarding chip responsible for processing packets. Taking software implementation as an example, such as... Figure 10As shown, a device in a logical sense is formed by the CPU of its host electronic device reading the corresponding computer program from non-volatile memory into memory and running it. This embodiment provides an inter-satellite routing device for a low-Earth orbit (LEO) constellation network, applied to any satellite node in the LEO constellation network. The device includes:

[0104] The routing calculation unit 1000 is used to autonomously learn and calculate routes in the constellation network based on the Open Shortest Path First protocol and / or Border Gateway protocol running in the constellation network, and store a routing table of the current network topology; the routing table includes at least the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to every other node in the constellation network.

[0105] Hop count determination unit 1002 is used to determine the target north-south vertical hop count and the target east-west horizontal hop count from the current satellite node to the target satellite node based on the routing table in response to the routing forwarding service to the target satellite node.

[0106] The forwarding rectangle determination unit 1004 is used to determine whether a forwarding rectangle can be formed in the current network topology based on the target's north-south vertical hop count and the target's east-west horizontal hop count; wherein, the current satellite node and the target satellite node are the two opposite vertices of the forwarding rectangle, and the target's north-south vertical hop count and the target's east-west horizontal hop count are the two side lengths of the forwarding rectangle;

[0107] The output interface determination unit 1006 is used to determine the output interface for route forwarding based on the area of ​​the forwarding rectangle and the routing table when the forwarding rectangle can be formed.

[0108] In one embodiment of the present invention, the routing calculation unit is specifically used to: determine the neighboring satellite nodes connected to the current satellite node in the same orbit and across orbits respectively; send the current satellite node's route to each neighboring satellite node, and receive the route forwarded by each neighboring satellite node; calculate the north-south vertical hop count and east-west horizontal hop count of each other satellite node in the constellation network of the current satellite node based on the received route, so as to update the routing table of the current satellite node.

[0109] In one embodiment of the present invention, the routing calculation unit is further configured to perform the autonomous constellation network routing learning and calculation again when it is determined that the routing update conditions are met, in order to update the stored routing table.

[0110] In one embodiment of the present invention, the forwarding rectangle determination unit is specifically used to: determine that a forwarding rectangle can be formed in the current network topology when both the north-south vertical hop count and the east-west horizontal hop count of the target are not equal to 0.

[0111] In one embodiment of the present invention, the output interface determination unit is specifically used to: determine the latitude relationship between the current satellite node and the destination satellite node, and determine the order of cross-orbit forwarding and intra-orbit forwarding based on the latitude relationship; determine whether there is an output interface corresponding to the forwarding direction in the routing table according to the forwarding direction that comes first in the order; if it exists, determine the output interface corresponding to the forwarding direction as the output interface for routing forwarding; if it does not exist, reverse the order and continue to execute this step based on the adjusted order.

[0112] In one embodiment of the present invention, the output interface determination unit is specifically used to: determine the target output interface in the forwarding path corresponding to the multiple output interfaces of the routing table, wherein the forwarding path is located within the area of ​​the forwarding rectangle, determine all the target output interfaces as output interfaces for routing forwarding, and when there are multiple target output interfaces, perform routing forwarding through load sharing.

[0113] In one embodiment of the present invention, the output interface determination unit is further configured to, after determining the output interface as a route forwarding interface, determine whether to re-determine the output interface based on the traffic status and / or link status of the output interface.

[0114] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on an inter-satellite routing device for a low-Earth orbit constellation network. In other embodiments of the present invention, an inter-satellite routing device for a low-Earth orbit constellation network may include more or fewer components than illustrated, or combine some components, split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0115] The information interaction and execution process between the modules in the above-mentioned device are based on the same concept as the method embodiment of the present invention, and the specific details can be found in the description of the method embodiment of the present invention, and will not be repeated here.

[0116] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements an inter-satellite routing method for a low-Earth orbit constellation network according to any embodiment of this invention.

[0117] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform an inter-satellite routing method for a low-Earth orbit constellation network according to any embodiment of this invention.

[0118] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0119] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0120] Examples of storage media used to provide program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0121] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0122] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0123] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0124] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, or optical disk.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An inter-satellite routing method for a low-Earth orbit constellation network, characterized in that, The method, applicable to any satellite node in a low-Earth orbit constellation network, includes: Based on the Open Shortest Path First (OSPF) protocol and / or Border Gateway Protocol (BGP) running in the constellation network, the system autonomously learns and calculates routes within the constellation network and stores a routing table of the current network topology. This routing table includes at least the north-south vertical hop count (V-hop) and the east-west horizontal hop count (H-hop) from the current satellite node to every other node in the constellation network. V-hop represents the number of hops required for forwarding from the current satellite node to the destination satellite node in the north-south direction; the sign of V-hop indicates the relationship between the forwarding direction and the satellite's movement direction. H-hop represents the number of hops required for forwarding from the current satellite node to the destination satellite node in the east-west direction; H-hop is defined as having positive and negative values. V-hop information is carried through extended OSPF attributes, and H-hop information is carried through extended BGP attributes. During topology forwarding, V-hop and H-hop are communicated to other satellite nodes via OSPF and BGP attributes. In response to the routing forwarding service to the destination satellite node, the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to the destination satellite node are determined based on the routing table; Based on the target's north-south vertical hop count and the target's east-west horizontal hop count, it is determined whether a forwarding rectangle can be formed in the current network topology; wherein, the current satellite node and the target satellite node are the two opposite vertices of the forwarding rectangle, and the target's north-south vertical hop count and the target's east-west horizontal hop count are the two side lengths of the forwarding rectangle, respectively; If the forwarding rectangle can be formed, the output interface for route forwarding is determined based on the area of ​​the forwarding rectangle and the routing table. The output interface for route forwarding is located within the area of ​​the forwarding rectangle.

2. The method according to claim 1, characterized in that, The autonomous learning and calculation of routes in the constellation network includes: Identify adjacent satellite nodes that are connected to the current satellite node in the same orbit and across orbits, respectively; Send the current satellite node's route to each neighboring satellite node, and receive the route forwarded by each neighboring satellite node; Based on the received routes, the current satellite node calculates the north-south vertical hop count and the east-west horizontal hop count for each other satellite node in the constellation network to update the routing table of the current satellite node.

3. The method according to claim 1, characterized in that, Also includes: According to the preset route update conditions, when it is determined that the route update conditions are met, the autonomous constellation network route learning and calculation is performed again to update the stored routing table.

4. The method according to claim 1, characterized in that, The step of determining whether a forwarding rectangle can be formed in the current network topology based on the target's north-south vertical hop count and the target's east-west horizontal hop count includes: When both the north-south vertical hop count and the east-west horizontal hop count of the target are not equal to 0, it is determined that a forwarding rectangle can be formed in the current network topology.

5. The method according to claim 4, characterized in that, The output interface for determining route forwarding based on the region of the forwarding rectangle and the routing table includes: Determine the latitude relationship between the current satellite node and the target satellite node, and determine the order of cross-orbit forwarding and intra-orbit forwarding based on the latitude relationship; According to the forwarding direction that comes first in the order, determine whether there is an output interface in the routing table that corresponds to the forwarding direction; if there is, determine the output interface that corresponds to the forwarding direction as the output interface for routing forwarding; if there is no, reverse the order and continue to execute this step based on the adjusted order.

6. The method according to claim 4, characterized in that, The output interface for determining route forwarding based on the region of the forwarding rectangle and the routing table includes: In the forwarding paths corresponding to the multiple output interfaces of the routing table, the target output interfaces located within the area of ​​the forwarding rectangle are determined. All the target output interfaces are determined as output interfaces for routing forwarding. When there are multiple target output interfaces, routing forwarding is performed through load balancing.

7. The method according to claim 5 or 6, characterized in that, After the output interface is determined to be used for routing forwarding, the following is also included: Based on the traffic status and / or link status of the output interface, determine whether to re-determine the output interface.

8. An inter-satellite routing device for a low-Earth orbit constellation network, characterized in that, An apparatus applicable to any satellite node in a low-Earth orbit (LEO) constellation network, used to execute the inter-satellite routing method for any of the LEO constellation networks described in claims 1-7 above, the apparatus comprising: The routing calculation unit is used to autonomously learn and calculate routes in the constellation network based on the Open Shortest Path First (OSB) protocol and / or Border Gateway Protocol (BGLP) running in the constellation network, and to store a routing table of the current network topology; the routing table includes at least the number of hops in the north-south vertical direction and the number of hops in the east-west horizontal direction from the current satellite node to every other node in the constellation network. The hop count determination unit is used to determine the target north-south vertical hop count and the target east-west horizontal hop count from the current satellite node to the target satellite node based on the routing table in response to the routing forwarding service to the target satellite node. The forwarding rectangle determination unit is used to determine whether a forwarding rectangle can be formed in the current network topology based on the target's north-south vertical hop count and the target's east-west horizontal hop count; wherein, the current satellite node and the target satellite node are the two opposite vertices of the forwarding rectangle, and the target's north-south vertical hop count and the target's east-west horizontal hop count are the two side lengths of the forwarding rectangle, respectively; The output interface determination unit is used to determine the output interface for route forwarding based on the area of ​​the forwarding rectangle and the routing table when the forwarding rectangle can be formed.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program, implements the method as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method of any one of claims 1-7.

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