A method and system for managing intersatellite routing topology of low-orbit satellites

Abstract

The present invention discloses a method and system for managing intersatellite routing topology of low-orbit satellites, the method comprising: an overhead satellite node receives a topology version message sent by a ground network controller, and returns a topology version response message to the ground network controller; the overhead satellite node receives a detailed topology message sent by the ground network controller, and the detailed topology message carries a message sequence number; the overhead satellite node compares whether the first message sequence number received this time is continuous with the second message sequence number received last time, encapsulates a detailed topology response message according to the comparison result and returns it to the ground network controller; the overhead satellite node sends a successfully received detailed topology message to a neighboring satellite node through a direct-connection port, and the neighboring satellite node sends a detailed topology message to other satellite nodes connected thereto. Thus, the present invention maintains the topology of the entire network through satellite nodes, thereby realizing efficient service transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of low-orbit satellite routing exchange, and in particular to a method and system for managing low-orbit satellite inter-satellite routing topology. Background Art

[0002] Low-orbit satellite constellations have inter-satellite routing and exchange capabilities, and can efficiently transmit data. Due to the short orbital period of low-orbit satellites, their network topology changes rapidly, and there are different types of random failures in the network. However, traditional ground network routing in the prior art cannot be adapted to low-orbit satellite networks. Therefore, how to manage the inter-satellite routing topology of low-orbit satellites to adapt to changes in links in the network and perform fast rerouting has become one of the technical problems that need to be solved in the prior art. Summary of the invention

[0003] The present invention proposes a low-orbit satellite inter-satellite routing topology management method and system to solve the problem of how to manage the low-orbit satellite inter-satellite routing topology to adapt to the changes of links in the network and perform fast rerouting.

[0004] To solve this technical problem, this specification provides the following technical solutions:

[0005] In a first aspect, this specification provides a method for managing inter-satellite routing topology of a low-orbit satellite, including:

[0006] The overhead satellite node receives a topology version message sent by the ground network controller, wherein the topology version message carries a topology version number, and the topology version number is defined by the ground network controller;

[0007] The overhead satellite node returns a topology version response message to the ground network controller in response to the topology version message, where the topology version response message is encapsulated according to the topology version number;

[0008] The overhead satellite node receives a detailed topology message sent by the ground network controller based on the topology version response message, wherein the detailed topology message carries a first message sequence number;

[0009] The overhead satellite node compares whether the first message sequence number received this time is continuous with the second message sequence number received last time; and

[0010] Encapsulating a detailed topology response message according to the comparison result and returning it to the ground network controller, wherein the detailed topology response message is used to instruct the ground network controller whether to retransmit the sent detailed topology message;

[0011] The overhead satellite node sends a successfully received detailed topology message to a neighboring satellite node connected to itself through a direct connection port, and the neighboring satellite node sends a detailed topology message to other satellite nodes connected to it.

[0012] Optionally, a detailed topology response message is encapsulated according to the comparison result, specifically including:

[0013] If the first message sequence number and the second message sequence number are continuous, it is determined that the detailed topology message is received successfully, the first sequence number is recorded, and an error code field indicating successful reception is encapsulated in the detailed topology response message;

[0014] If the first message sequence number and the second message sequence number are not continuous, comparing the first message sequence number and the second message sequence number;

[0015] If the first message sequence number is greater than the second message sequence number, an error code and the second message sequence number are encapsulated in the detailed topology response message.

[0016] Optionally, the topology version message carries a first version number; and

[0017] The overhead satellite node returns a topology version response message to the ground network controller in response to the topology version message, specifically including:

[0018] The overhead satellite node determines whether the topology version message is received successfully according to the first version number and the second version number stored locally; and

[0019] According to the judgment result, the corresponding error code field is encapsulated in the topology version response message and the topology version response message is returned to the ground network controller. The error code field is used to indicate whether the topology version message is transmitted successfully or incorrectly, and the type of error that occurs during transmission.

[0020] Optionally, the method further includes:

[0021] Receiving a link update message sent by a neighbor satellite node, wherein the link update message carries a link identifier and a third sequence number;

[0022] Searching for a fourth sequence number of a corresponding link in a locally stored topology information table according to the link identifier;

[0023] Compare the third sequence number with the fourth sequence number, and if the third sequence number is greater than the fourth sequence number, update the local topology information table, return a link update response message to the neighbor satellite node, and forward the link update message to other neighbor satellite nodes through other ports except for receiving the link update message, and the other neighbor satellite nodes forward the link update message to other satellite nodes;

[0024] If the third sequence number is the same as the fourth sequence number, determining that the local link information has been updated and returning a link update response message to the neighbor satellite node;

[0025] If the third sequence number is smaller than the fourth sequence number, the corresponding link information is encapsulated according to the link identifier and a link update response message is sent back.

[0026] In a second aspect, this specification also provides a low-orbit satellite inter-satellite routing topology management method, including:

[0027] The ground network controller sends a topology version message to the overhead satellite node, wherein the topology version message carries a topology version number;

[0028] receiving a topology version response message returned by the overhead satellite node, wherein the topology version response message is encapsulated by the overhead satellite node according to the topology version number;

[0029] When it is determined according to the topology version response message that a detailed topology message needs to be sent to the overhead satellite node, a detailed topology message is sent to the overhead satellite node according to the locally generated topology information table, wherein the detailed topology message carries a first message sequence number;

[0030] receiving a detailed topology response message returned by the overhead satellite node, wherein the detailed topology response message is encapsulated by the overhead satellite node according to a comparison result between the first message sequence number and a second message sequence number stored locally;

[0031] It is determined whether the detailed topology message needs to be retransmitted according to the detailed topology response message.

[0032] Optionally, the detailed topology response message carries an error code field and other sequence number fields; and

[0033] While sending a detailed topology message to the overhead satellite node, it also includes:

[0034] Adding the detailed topology message to a retransmission queue and starting a retransmission timer; and

[0035] Determining whether the detailed topology message needs to be retransmitted according to the detailed topology response message specifically includes:

[0036] If it is determined according to the error code field that the detailed topology message is successfully transmitted, deleting the detailed topology message from the retransmission queue;

[0037] If it is determined according to the error code field that the detailed topology message is transmitted incorrectly, retransmitting the detailed topology message between the second message sequence number and the first message sequence number according to the second message sequence number in the other sequence number field;

[0038] When the retransmission timer expires, retransmitting the detailed topology message in the retransmission queue; and

[0039] If the number of retransmissions is greater than a preset threshold, it is determined that the transmission of the detailed topology message whose number of retransmissions is greater than the preset threshold has failed.

[0040] In a third aspect, the present specification also provides a low-orbit satellite inter-satellite routing topology management system, including a ground network controller and a satellite node, wherein the satellite node includes an overhead satellite node, the overhead satellite node communicates with the ground network controller via a feeder link, and each satellite node communicates with each other via an inter-satellite link, wherein:

[0041] The ground network controller is used to send a topology version message to the overhead satellite node, wherein the topology version message carries a topology version number; when it is determined according to the topology version response message that a detailed topology message needs to be sent to the overhead satellite node, a detailed topology message is sent to the overhead satellite node according to a locally generated topology information table, wherein the detailed topology message carries a first message sequence number; and whether the detailed topology message needs to be retransmitted according to the detailed topology response message;

[0042] The overhead satellite node is used to return a topology version response message to the ground network controller for the topology version message, and the topology version response message is encapsulated according to the topology version number; compare whether the message sequence number received this time is continuous with the second message sequence number received last time; and encapsulate a detailed topology response message based on the comparison result and return it to the ground network controller; send a successfully received detailed topology message to a neighbor satellite node connected to itself through a direct connection port, and the neighbor satellite node sends a detailed topology message to other satellite nodes connected to it.

[0043] Optionally, the overhead satellite node is specifically used to determine that the detailed topology message is successfully received if the first message sequence number and the second message sequence number are continuous, record the first sequence number and encapsulate the error code field of successful reception in the detailed topology response message; if the first message sequence number and the second message sequence number are not continuous, compare the size of the first message sequence number and the second message sequence number; if the first message sequence number is greater than the second message sequence number, encapsulate the error code and the second message sequence number in the detailed topology response message.

[0044] Optionally, the topology version message carries a first version number; and the overhead satellite node is specifically used to determine whether the topology version message is successfully received based on the first version number and a second version number stored locally; and based on the judgment result, encapsulates a corresponding error code field in the topology version response message and returns a topology version response message to the ground network controller, wherein the error code field is used to indicate whether the topology version message is transmitted successfully or the topology version message is transmitted incorrectly and the type of error that occurs during transmission.

[0045] Optionally, the overhead satellite node is also used to receive a link update message sent by a neighboring satellite node, the link update message carrying a link identifier and a third sequence number; search for the fourth sequence number of the corresponding link in the locally stored topology information table according to the link identifier; compare the third sequence number with the fourth sequence number, and if the third sequence number is greater than the fourth sequence number, update the local topology information table, return a link update response message to the neighboring satellite node, and forward the link update message to other neighboring satellite nodes through other ports except for receiving the link update message, and the other neighboring satellite nodes forward the link update message to other satellite nodes; if the third sequence number is the same as the fourth sequence number, determine that the local link information has been updated and return a link update response message to the neighboring satellite node; if the third sequence number is less than the fourth sequence number, encapsulate the corresponding link information according to the link identifier and send back the link update response message.

[0046] Optionally, the detailed topology response message carries an error code field and other sequence number fields; and the ground network controller is also used to add the detailed topology message to a retransmission queue and start a retransmission timer while sending the detailed topology message to the overhead satellite node; if it is determined according to the error code field that the detailed topology message is successfully transmitted, the detailed topology message is deleted from the retransmission queue; if it is determined according to the error code field that the detailed topology message is transmitted incorrectly, the detailed topology message between the second message sequence number and the first message sequence number is retransmitted according to the second message sequence number in the other sequence number fields; when the retransmission timer expires, the detailed topology message in the retransmission queue is retransmitted; and if the number of retransmissions is greater than a preset threshold, it is determined that the transmission of the detailed topology message with a number of retransmissions greater than the preset threshold has failed.

[0047] At least one of the above technical solutions adopted in this specification can achieve the following beneficial effects:

[0048] The present invention provides a method and system for managing the topology of intersatellite routing of low-orbit satellites. In an embodiment of the present invention, when a topology information table changes, a ground network controller first sends a topology version message to an overhead satellite node. The overhead satellite node compares the version information of the local topology information table through a response. When it is determined that an update is required, the overhead satellite node returns a response message to the ground network controller. The ground network controller sends a detailed topology message to the overhead satellite node based on the received response message. In order to improve the reliability of sending the detailed topology message, in an embodiment of the present invention, a message sequence number is carried in the detailed topology message. In this way, the overhead satellite node compares the message sequence number received last time locally with the message sequence number received this time. The received message sequence number determines whether the detailed topology message is transmitted incorrectly, and notifies the ground network controller in the corresponding response message. The ground network controller determines whether the detailed topology message needs to be retransmitted and the sequence number of the message to be retransmitted based on the received response message. The successfully transmitted detailed topology message is sent by the overhead satellite node to the neighboring satellite node directly connected to it, and the neighboring satellite node then forwards it to other satellite nodes connected to it, thereby realizing reliable update of the topology routing of the entire network. In the above process, the topology of the entire network is updated by the overhead satellite node, which provides a reliable basis for the inter-satellite routing protocol to calculate the routing table, can adapt to network emergencies, and thus realize uninterrupted and efficient business transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0050] Figure 1A schematic diagram of the composition of a low-orbit satellite inter-satellite routing topology management system according to an embodiment of the present invention;

[0051] Figure 2 A schematic diagram of a flow chart of a method for managing inter-satellite routing topology of a low-orbit satellite according to an embodiment of the present invention;

[0052] Figure 3 The figure is a flow chart of another method for managing inter-satellite routing topology of low-orbit satellites according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of this specification more clear, the technical solutions of this specification will be clearly and completely described below in combination with the specific embodiments of this specification and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of this specification, not all of them. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this specification.

[0054] As described herein, the term “including” and various variations thereof may be understood as open-ended terms meaning “including but not limited to,” and the term “one embodiment” may be understood as “at least one embodiment.”

[0055] The technical solutions provided by the embodiments of this specification are described in detail below in conjunction with the accompanying drawings.

[0056] Embodiment 1

[0057] like Figure 1 As shown, it is a schematic diagram of the structure of the low-orbit satellite inter-satellite routing topology management system provided by an embodiment of the present invention. The low-orbit satellite inter-satellite routing topology management system provided by an embodiment of the present invention includes a ground network controller, an overhead satellite node and other satellite nodes. For the convenience of description, the satellite node directly connected to the overhead satellite node is called a neighbor satellite node. Among them, the surface network controller connects the satellite through a feeder link to realize information interaction between the ground and the satellite node. Each satellite node and the inter-satellite link constitutes an inter-satellite network to realize data transmission across satellites and domains. When the ground network controller sends the topology information table, it adopts the strategy of broadcast detection of the topology version message first, and reliability transmission of the subsequent topology detailed message, and performs loop-free full-network flooding. When there is a link change, the source satellite node that generates the link update message sends a message to all neighbor satellite nodes and the ground network controller. The neighbor satellite node autonomously determines whether it needs to continue flooding according to the sequence number, and sends back a response message to complete the reliable and loop-free full-network diffusion of the message.

[0058] It should be noted that the process of transmitting messages between the ground network controller and overhead satellite nodes, between overhead satellite nodes and their neighboring satellite nodes, and other satellite nodes is basically the same. For the sake of ease of description, the message transmission process between the ground network controller and overhead satellite nodes is used as an example in the embodiment of the present invention.

[0059] Optionally, data is transmitted between the ground and overhead satellites by unicast, and no anti-loop is required. Data is transmitted between overhead satellites and other satellites by broadcast. Other satellites determine whether subsequent detailed topology messages are needed based on the sequence number of the version message. A satellite may receive the same version message from different interfaces. The version message mechanism has an anti-loop effect, and subsequent detailed messages are received by the interface that received them first.

[0060] based on Figure 1 The low-orbit satellite inter-satellite routing topology management system shown in the figure, the embodiment of the present invention provides a low-orbit satellite inter-satellite routing topology management method, Figure 2 This is a flow chart of a method for managing inter-satellite routing topology of a low-orbit satellite provided in an embodiment of this specification. The method is executed by a central control or processor of an overhead satellite node. Figure 2 , the method may specifically include the following steps:

[0061] Step 102: The overhead satellite node receives a topology version message sent by the ground network controller.

[0062] In specific implementation, after calculating the topology information table of time slices, the ground network controller defines a topology version number and encapsulates it into a topology version message and sends it to the overhead satellite node. Specifically, the overhead satellite node includes a satellite-to-ground topology information interaction module, which receives the topology version message sent by the ground network controller through the satellite-to-ground topology information interaction module, and the topology version message carries the first version number.

[0063] Step 104: The overhead satellite node returns a topology version response message to the ground network controller in response to the topology version message.

[0064] After receiving the topology version message, the overhead satellite node determines whether a subsequent detailed topology message is needed based on the version number carried in the topology version message, and replies with a topology version response message to the ground network controller.

[0065] Specifically, the overhead satellite node compares the first version number of the topology information table carried in the topology version message with the second version number of the topology information table stored locally. If the first version number is greater than the second version number, it is determined that the topology information table has been updated, and encapsulates the indication information that a detailed topology message is needed in the topology version response message. A field carrying indication information can be set in the topology version response message, and the field value of the field indicates that the ground network controller needs to continue transmitting the detailed topology message. The ground network controller determines whether it needs to continue transmitting the detailed topology message based on the field value of the field.

[0066] In specific implementation, after receiving the topology version message, the overhead satellite node forwards the topology version message to the neighboring satellite node directly connected to it. After the overhead satellite node receives the detailed message, the neighboring satellite node forwards the topology version message to other satellite nodes connected to it. In specific implementation, the topology version message can be propagated between other satellite nodes according to the following process: For the convenience of description in the future, the satellite node that sends the topology version message is referred to as the sender, and the satellite node that receives the topology version message is referred to as the receiver. The sender sends the topology version message received by itself to the receiver. The receiver compares the first version number carried in the received topology version message with the third version number stored locally. If the first version number is greater than the third version number, it is determined that the topology information table has been updated, and the indication information that a detailed topology message is required is encapsulated in the topology version response message returned to the sender. If the first version number is the same as the third version number, it is indicated that the receiving end has received the same topology version message, and the indication information that a detailed topology message is not required is encapsulated in the returned topology version response message. If the first version number is smaller than the third version number, the indication information of the smaller version number is encapsulated in the returned topology version response message, and the receiving end encapsulates the topology summary message and sends it to the sending end, attempting to update the topology information table of the sending end.

[0067] It should be noted that after the interaction between the ground and the satellite is completed, the forwarding between satellites is carried out. The topology version message is sent by broadcast, that is, the overhead satellite node sends the topology version message to all directly connected satellite nodes, and the non-overhead satellite node sends the topology version message from other ports except the receiving port to the directly connected satellite nodes; the topology detailed message is unicast sent by the sender according to the topology version response message returned by the receiver, that is, the sender sends the detailed topology message to the receiver that needs the detailed topology message according to the indication information carried in the topology version response message returned by the receiver.

[0068] In addition, the overhead satellite node can also determine whether the topology version message is received successfully based on the first version number and the locally stored second version number; and encapsulate the corresponding error code field in the topology version response message based on the judgment result and return the topology version response message to the ground network controller, where the error code field is used to indicate whether the topology version message is transmitted successfully or the topology version message is transmitted incorrectly and the type of error that occurred during the transmission error, so that the ground network controller retransmits the topology version message according to the error type.

[0069] Step 106: The overhead satellite node receives a detailed topology message sent by the ground network controller based on the topology version response message.

[0070] In this step, after receiving the topology version response message, if the ground network controller determines that the detailed topology message needs to be transmitted according to the indication information therein, it sends the detailed topology message to the overhead satellite node. In specific implementation, in order to ensure the reliability of information transmission, in the embodiment of the present invention, a sequence number confirmation response mechanism is used to transmit the detailed topology message.

[0071] Specifically, the ground network controller carries a sequence number in the detailed topology message sent, and the sequence numbers of the detailed topology messages sent continuously are continuous. While sending, the ground network controller adds the sent detailed topology message to the locally maintained message retransmission queue.

[0072] Step 108: The overhead satellite node compares the first message sequence number received this time with the second message sequence number received last time to see if they are continuous, encapsulates a detailed topology response message based on the comparison result, and returns it to the ground network controller.

[0073] After receiving the detailed topology message, the overhead satellite node parses the message, determines the processing method and whether it needs to record the sequence number of this message; if the sequence number in the message is continuous with the sequence number received last time, it is considered that the reception is successful and the sequence number is recorded; if the sequence number is discontinuous with the sequence number received last time, the size of the sequence number is determined. If the received sequence number is smaller, it is considered that this message is a retransmitted message, and the data is parsed but the sequence number is not recorded; if the received sequence number is larger, it is considered that part of the message between the two sequence numbers has not been successfully received, and the sequence number received last time is encapsulated into the other sequence number fields of the detailed topology response message, requiring the sender to retransmit the sequence number message that has not been received, and record the sequence number; if the sequence numbers are the same, it is considered that this message has been received and no processing is performed.

[0074] In one embodiment, the overhead satellite node compares whether the first message sequence number received this time is continuous with the second message sequence number received last time, marks the error code and other sequence numbers according to the comparison result, encapsulates the detailed topology response message, and sends the detailed topology response message to the ground network controller.

[0075] Specifically, if the first message sequence number and the second message sequence number are continuous, it is determined that the detailed topology message is received successfully, the first sequence number is recorded and the error code field of successful reception is encapsulated in the detailed topology response message; if the first message sequence number and the second message sequence number are not continuous, the first message sequence number and the second message sequence number are compared; if the first message sequence number is greater than the second message sequence number, the error code and the second message sequence number are encapsulated in the detailed topology response message.

[0076] Step 110: The overhead satellite node sends a successfully received detailed topology message to a neighboring satellite node connected to itself through a direct connection port, and the neighboring satellite node sends a detailed topology message to other satellite nodes connected to it.

[0077] Similar to the process of updating the topology information table between the ground network controller and the overhead satellite node, the overhead satellite node uses the topology version message to broadcast detection first, and determines whether it is necessary to transmit subsequent detailed topology messages to the neighboring satellite nodes according to the version number carried in the topology version message. If subsequent detailed topology messages are required, the sequence number confirmation response mechanism is used to continue to transmit detailed topology messages to the neighboring satellite nodes; and

[0078] The neighboring satellite node uses the topology version message to broadcast detection first, and judges whether it is necessary to send subsequent detailed topology messages to other satellite nodes connected to it according to the version number carried in the topology version message. If subsequent detailed topology messages are needed, the sequence number confirmation response mechanism is used to continue to transmit detailed topology messages to other satellite nodes. In this way, the topology information table between each satellite is updated.

[0079] On this basis, an embodiment of the present invention further provides a method for updating a topology information table due to a change in an inter-satellite link. In specific implementation, when any satellite node detects a change in a link connected to itself, a link update message can be sent to a satellite node directly connected to it, and the satellite node receiving the link update message forwards it to other satellite nodes connected to it, and so on, to finally implement a full network routing update. In the embodiment of the present invention, the process of processing a link update message by an overhead satellite node is taken as an example for description. The overhead satellite node receives a link update message sent by a neighbor satellite node, in which the link update message carries a link identifier and a third sequence number; searches for the fourth sequence number of the corresponding link in the locally stored topology information table according to the link identifier; compares the third sequence number with the fourth sequence number, and if the third sequence number is greater than the fourth sequence number, updates the local topology information table, returns a link update response message to the neighbor satellite node, and forwards the link update message to other neighbor satellite nodes through other ports except for receiving the link update message, and the other neighbor satellite nodes forward the link update message to other satellite nodes; if the third sequence number is the same as the fourth sequence number, determines that the local link information has been updated and returns a link update response message to the neighbor satellite node; if the third sequence number is less than the fourth sequence number, encapsulates the corresponding link information according to the link identifier and sends back the link update response message.

[0080] It should be noted that the process of other satellite nodes processing link update messages is the same as the process of overhead satellite nodes processing link update messages, which will not be repeated here.

[0081] Based on this, in this embodiment, each satellite node and inter-satellite link forms an inter-satellite network to realize cross-satellite and cross-domain data transmission. When there is a link change, the source satellite node that generates a link update message sends the message to all neighboring satellite nodes and the ground network controller. The neighboring satellite node independently determines whether to continue flooding based on the sequence number and sends back a response message to complete reliable and loop-free full-network diffusion of the message.

[0082] Embodiment 2

[0083] Figure 3 A flowchart of a low-orbit satellite inter-satellite routing topology management method provided in Embodiment 2 of this specification, wherein the method may specifically include the following steps:

[0084] Step 202: The ground network controller sends a topology version message to the overhead satellite node.

[0085] The topology version message carries a topology version number.

[0086] It should be noted that one implementation of step 202 may be:

[0087] The ground controller calculates a topology information table divided into time slices, defines a version number and encapsulates it into a topology version message, and sends the topology version message to the overhead satellite node.

[0088] In a specific implementation, while sending a detailed topology message to an overhead satellite node, the detailed topology message is added to a retransmission queue and a retransmission timer is started; if it is determined based on the error code field that the detailed topology message is successfully transmitted, the detailed topology message is deleted from the retransmission queue; if it is determined based on the error code field that a detailed topology message transmission error occurs, the detailed topology message between the second message sequence number and the first message sequence number is retransmitted based on the second message sequence number in other sequence number fields; when the retransmission timer expires, the detailed topology message in the retransmission queue is retransmitted; if the number of retransmissions is greater than a preset threshold, it is determined that the transmission of the detailed topology message with a number of retransmissions greater than the preset threshold has failed.

[0089] Step 204: Receive a topology version response message returned by the overhead satellite node.

[0090] The topology version response message is encapsulated by the overhead satellite node according to the topology version number.

[0091] It should be noted that one implementation of step 204 may be:

[0092] The ground controller receives a topology version response message returned by the overhead satellite node, where the topology version response message is encapsulated and sent according to the topology version number after the overhead satellite node completes version number judgment.

[0093] Step 206: When it is determined according to the topology version response message that a detailed topology message needs to be sent to the overhead satellite node, a detailed topology message is sent to the overhead satellite node according to the locally generated topology information table.

[0094] The detailed topology message carries a first message sequence number.

[0095] It should be noted that one implementation of step 206 may be:

[0096] The ground network controller determines whether it is necessary to send a detailed topology message to the overhead satellite node based on the topology version response message. If so, a sequence number confirmation response mechanism is used to send a detailed topology message to the overhead satellite node to ensure the reliability of information transmission.

[0097] Step 208: Receive a detailed topology response message returned by the overhead satellite node.

[0098] The detailed topology response message is encapsulated by the overhead satellite node according to a comparison result between the first message sequence number and the second message sequence number stored locally.

[0099] Step 210: Determine whether the detailed topology message needs to be retransmitted according to the detailed topology response message.

[0100] It should be noted that one implementation of step 210 may be:

[0101] The ground network controller deletes the corresponding message in the retransmission queue, determines whether the detailed topology message needs to be retransmitted based on the error code in the detailed topology response message, and determines the message sequence number that needs to be retransmitted based on other sequence number fields in the detailed topology response message.

[0102] Based on this, in this embodiment, the ground network controller connects to the satellite through a feeder link to realize information interaction between the ground and satellite nodes. When the ground network controller sends the topology information table, it uses the topology version message to broadcast detection first, and then broadcasts the topology detailed message according to the reliability transmission strategy to perform loop-free full-network flooding.

[0103] Embodiment 3

[0104] based on Figure 1 In a low-orbit satellite inter-satellite routing topology management system shown:

[0105] The ground network controller is used to send a topology version message to the overhead satellite node, wherein the topology version message carries a topology version number; when it is determined according to the topology version response message that a detailed topology message needs to be sent to the overhead satellite node, a detailed topology message is sent to the overhead satellite node according to a locally generated topology information table, wherein the detailed topology message carries a first message sequence number; and whether the detailed topology message needs to be retransmitted according to the detailed topology response message;

[0106] The overhead satellite node is used to return a topology version response message to the ground network controller for the topology version message, and the topology version response message is encapsulated according to the topology version number; compare whether the message sequence number received this time is continuous with the second message sequence number received last time; and encapsulate a detailed topology response message based on the comparison result and return it to the ground network controller; send a successfully received detailed topology message to a neighbor satellite node connected to itself through a direct connection port, and the neighbor satellite node sends a detailed topology message to other satellite nodes connected to it.

[0107] Embodiment 4

[0108] Embodiment 4 of the present specification provides a method for managing inter-satellite routing topology of low-orbit satellites, and the method may specifically include the following steps:

[0109] Step 1: The ground controller calculates the topology information table divided into time slices, defines the version number and encapsulates it into a topology version message and sends it to the satellite node; the satellite-ground topology information interaction module of the satellite node is responsible for interacting with the topology information table: the satellite-ground topology information interaction module receives the topology version message and replies with the topology version response message; to ensure reliability, a serial number confirmation response mechanism is used to receive detailed topology messages.

[0110] It should be noted that the version number judgment does not appear in step 1 because the satellite topology information is uploaded by the ground network controller, which has the latest version number.

[0111] Step 2: The inter-satellite topology information diffusion module is responsible for spreading the received topology information to the entire network: using the topology version message to broadcast detection first; judging whether subsequent detailed topology messages are required based on the version number carried in the topology version message, and replying with a topology version response message; if necessary, using the sequence number confirmation response mechanism to continue transmitting the detailed topology message, if not necessary, no further processing is performed.

[0112] It should be noted that the serial number confirmation response mechanism in step 1 and step 2 includes:

[0113] When the sender sends a detailed topology message, it carries a sequence number field. The sequence numbers of the messages sent continuously are consecutive integers. The sender adds the messages to the retransmission queue.

[0114] When the receiving end receives the detailed topology message, it determines the processing method and whether it needs to record the sequence number of this message; if the sequence number in the message is continuous with the sequence number received last time, it is considered that the reception is successful and the sequence number is recorded; if the sequence number is discontinuous with the sequence number received last time, the size of the sequence number is determined; if the received sequence number is smaller, it is considered that this message is a retransmitted message and the sequence number is not recorded; if the received sequence number is larger, it is considered that part of the message between the two sequence numbers has not been successfully received, and the sequence number received last time is encapsulated into other sequence number fields of the detailed topology response message, and the sequence number is recorded; if the sequence numbers are the same, it is considered that this message has been received and no processing is performed;

[0115] The receiving end sends a detailed topology response message, which carries the sequence number of the detailed topology message and marks the error code and other sequence numbers according to the judgment result in the previous step;

[0116] The sender receives the detailed topology response message, deletes the corresponding message in the retransmission queue, determines whether to retransmit based on the error code, and determines the message sequence number that needs to be retransmitted based on other sequence number fields;

[0117] If the retransmission timer of the sending end times out, the message that has timed out in the retransmission queue is sent; if the number of retransmissions exceeds 3 times, the sending is considered to have failed.

[0118] Optionally, determine whether subsequent detailed topology messages are needed based on the version number carried in the topology version message, specifically including: comparing the version number carried in the message with the local version number; if the version number in the message is larger, the topology information carried in the message is updated and subsequent detailed topology messages need to be transmitted; if the version numbers are the same, the same message has been received; if the version number in the message is smaller, it is considered that the topology information of the sender is lagging, and the topology version message of the receiving end is encapsulated and sent to the sender to update the topology information of the sender.

[0119] Optionally, the topology version message is sent by broadcast. The overhead satellite node sends the topology version message to all directly connected satellite nodes, and the non-overhead satellite node sends the topology version message to the directly connected satellite nodes from ports other than the receiving port; the topology detail message is sent by unicast based on the received topology version response message.

[0120] Step 3: When an emergency causes an intersatellite link change, the intersatellite link abnormal diffusion module generates and broadcasts a link update message, updates the topology information table of the entire network and feeds back the link change to the ground network controller. The source satellite node that generates the link update message broadcasts the message from all ports.

[0121] The link update message carries a sequence number field for determining whether the link information is new or old.

[0122] Optionally, the intersatellite link anomaly diffusion module compares the sequence number in the message with the sequence number of the same link in the satellite topology information table. If the sequence number in the message is larger, the message is parsed and the local topology information table is updated, and a link update response message is replied, and the link update message is flooded from ports other than the receiving port; if the sequence numbers are the same, a link update response message is replied, and it is considered that it has been received and no further processing is performed; if the sequence number in the message is smaller, the link information is encapsulated and the link update message is sent back to update the topology information table of the other end.

[0123] Optionally, when sending a link update message, the message is added to a retransmission queue until a link update response message sent by a directly connected satellite node is received or a link update message with a larger link sequence number is received, and the message is deleted from the retransmission queue, otherwise, the link update message is resent.

[0124] Step 4: The ground network controller receives the link update message and updates the local topology information table.

[0125] Based on this, this embodiment completes the topology management of low-orbit satellite inter-satellite routing, synchronizes the topology information table of the satellite node and the ground network controller, and realizes a two-level control structure of the ground network controller and the satellite node: on the one hand, the ground network controller can centrally control and manage the service and network according to the topology information table; on the other hand, the satellite node also retains some controller functions, and can quickly converge and reroute when the topology changes, thereby avoiding service interruption and improving data transmission efficiency.

[0126] In summary, in the embodiment of the present invention, the network topology of the low-orbit satellite constellation has periodicity and predictability. In order to ensure the correct transmission of data, the ground network controller calculates and sends the topology information table to the satellite node, and the satellite node autonomously maintains the constellation topology changes and feeds back to the ground controller. The topology management module of the satellite node can maintain the topology information of the entire network, becoming the cornerstone of the routing table calculation in the inter-satellite routing protocol, and can adapt to the changes of the links in the network and perform fast rerouting to achieve efficient transmission of services.

[0127] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for managing inter-satellite routing topology of low-orbit satellites, characterized in that: include: The overhead satellite node receives a topology version message sent by the ground network controller, wherein the topology version message carries a topology version number, and the topology version number is defined by the ground network controller; The overhead satellite node returns a topology version response message to the ground network controller in response to the topology version message, where the topology version response message is encapsulated according to the topology version number; The overhead satellite node receives a detailed topology message sent by the ground network controller based on the topology version response message, wherein the detailed topology message carries a first message sequence number; The overhead satellite node compares whether the first message sequence number received this time is continuous with the second message sequence number received last time; as well as Encapsulating a detailed topology response message according to the comparison result and returning it to the ground network controller, wherein the detailed topology response message is used to instruct the ground network controller whether to retransmit the sent detailed topology message; The overhead satellite node sends a successfully received detailed topology message to a neighboring satellite node connected to itself through a direct connection port, and the neighboring satellite node sends a detailed topology message to other satellite nodes connected to it.

2. The method according to claim 1, characterized in that The detailed topology response message is encapsulated based on the comparison result, including: If the first message sequence number and the second message sequence number are continuous, it is determined that the detailed topology message is received successfully, the first message sequence number is recorded, and an error code field indicating successful reception is encapsulated in the detailed topology response message; If the first message sequence number and the second message sequence number are not continuous, comparing the first message sequence number and the second message sequence number; If the first message sequence number is greater than the second message sequence number, an error code and the second message sequence number are encapsulated in the detailed topology response message.

3. The method according to claim 1, characterized in that The topology version message carries a first version number; and The overhead satellite node returns a topology version response message to the ground network controller in response to the topology version message, specifically including: The overhead satellite node determines whether the topology version message is received successfully according to the first version number and the second version number stored locally; and According to the judgment result, the corresponding error code field is encapsulated in the topology version response message and the topology version response message is returned to the ground network controller. The error code field is used to indicate whether the topology version message is transmitted successfully or incorrectly, and the type of error that occurs during transmission.

4. The method according to claim 1, characterized in that Also includes: Receiving a link update message sent by a neighbor satellite node, wherein the link update message carries a link identifier and a third sequence number; Searching for a fourth sequence number of a corresponding link in a locally stored topology information table according to the link identifier; Compare the third sequence number with the fourth sequence number, and if the third sequence number is greater than the fourth sequence number, update the local topology information table, return a link update response message to the neighbor satellite node, and forward the link update message to other neighbor satellite nodes through other ports except for receiving the link update message, and the other neighbor satellite nodes forward the link update message to other satellite nodes; If the third sequence number is the same as the fourth sequence number, determining that the local link information has been updated and returning a link update response message to the neighbor satellite node; If the third sequence number is smaller than the fourth sequence number, the corresponding link information is encapsulated according to the link identifier and a link update response message is sent back.

5. A method for managing inter-satellite routing topology of low-orbit satellites, characterized in that: include: The ground network controller sends a topology version message to the overhead satellite node, wherein the topology version message carries a topology version number; receiving a topology version response message returned by the overhead satellite node, wherein the topology version response message is encapsulated by the overhead satellite node according to the topology version number; When it is determined according to the topology version response message that a detailed topology message needs to be sent to the overhead satellite node, a detailed topology message is sent to the overhead satellite node according to the locally generated topology information table, wherein the detailed topology message carries a first message sequence number; receiving a detailed topology response message returned by the overhead satellite node, wherein the detailed topology response message is encapsulated by the overhead satellite node according to a comparison result between the first message sequence number and a second message sequence number stored locally; It is determined whether the detailed topology message needs to be retransmitted according to the detailed topology response message.

6. The method according to claim 5, characterized in that The detailed topology response message carries an error code field and other sequence number fields; as well as While sending a detailed topology message to the overhead satellite node, it also includes: Adding the detailed topology message to a retransmission queue and starting a retransmission timer; and Determining whether the detailed topology message needs to be retransmitted according to the detailed topology response message specifically includes: If it is determined according to the error code field that the detailed topology message is successfully transmitted, deleting the detailed topology message from the retransmission queue; If it is determined according to the error code field that the detailed topology message is transmitted incorrectly, retransmitting the detailed topology message between the second message sequence number and the first message sequence number according to the second message sequence number in the other sequence number field; When the retransmission timer times out, retransmitting the detailed topology message in the retransmission queue; and If the number of retransmissions is greater than a preset threshold, it is determined that the transmission of the detailed topology message whose number of retransmissions is greater than the preset threshold has failed.

7. A low-orbit satellite inter-satellite routing topology management system, characterized in that: It includes a ground network controller and satellite nodes, wherein the satellite nodes include overhead satellite nodes, the overhead satellite nodes communicate with the ground network controller via a feeder link, and the satellite nodes communicate with each other via inter-satellite links, wherein: The ground network controller is used to send a topology version message to the overhead satellite node, wherein the topology version message carries a topology version number; when it is determined according to the topology version response message that a detailed topology message needs to be sent to the overhead satellite node, a detailed topology message is sent to the overhead satellite node according to a locally generated topology information table, wherein the detailed topology message carries a first message sequence number; and whether the detailed topology message needs to be retransmitted according to the detailed topology response message; The overhead satellite node is used to return a topology version response message to the ground network controller for the topology version message, and the topology version response message is encapsulated according to the topology version number; compare whether the message sequence number received this time is continuous with the second message sequence number received last time; and encapsulate a detailed topology response message based on the comparison result and return it to the ground network controller; send a successfully received detailed topology message to a neighbor satellite node connected to itself through a direct connection port, and the neighbor satellite node sends a detailed topology message to other satellite nodes connected to it.

8. The system according to claim 7, characterized in that The overhead satellite node is specifically used to determine that the detailed topology message is successfully received if the first message sequence number and the second message sequence number are continuous, record the first message sequence number and encapsulate the error code field of successful reception in the detailed topology response message; If the first message sequence number and the second message sequence number are not continuous, comparing the first message sequence number and the second message sequence number; If the first message sequence number is greater than the second message sequence number, an error code and the second message sequence number are encapsulated in the detailed topology response message.

9. The system according to claim 7, characterized in that The topology version message carries a first version number; and The overhead satellite node is specifically used to determine whether the topology version message is received successfully according to the first version number and the second version number stored locally; And based on the judgment result, the corresponding error code field is encapsulated in the topology version response message and the topology version response message is returned to the ground network controller, and the error code field is used to indicate whether the topology version message is transmitted successfully or incorrectly, and the type of error that occurs during the transmission error.

10. The system according to claim 7, characterized in that The overhead satellite node is also used to receive a link update message sent by a neighbor satellite node, wherein the link update message carries a link identifier and a third sequence number; search for a fourth sequence number of a corresponding link in a locally stored topology information table according to the link identifier; compare the third sequence number with the fourth sequence number, and if the third sequence number is greater than the fourth sequence number, update the local topology information table, return a link update response message to the neighbor satellite node, and forward the link update message to other neighbor satellite nodes through other ports except for receiving the link update message, and the other neighbor satellite nodes forward the link update message to other satellite nodes; If the third sequence number is the same as the fourth sequence number, determining that the local link information has been updated and returning a link update response message to the neighbor satellite node; If the third sequence number is smaller than the fourth sequence number, the corresponding link information is encapsulated according to the link identifier and a link update response message is sent back.

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