Disclosure of Invention
The invention provides a method and a system for managing a low-orbit satellite inter-satellite routing topology, which are used for solving the problem of how to manage the low-orbit satellite inter-satellite routing topology so as to adapt to the change of links in a network and perform quick rerouting.
In order to solve the technical problem, the specification provides the following technical scheme:
in a first aspect, the present disclosure provides a method for managing a topology of an inter-satellite route of a low-orbit satellite, including:
the method comprises the steps that a satellite node passing through the top receives a topology version message sent by a 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 aiming at the topology version message, wherein the topology version response message is packaged according to the topology version number;
the over-the-top 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 serial number;
the overhead satellite node compares whether the sequence number of the first message received at this time is continuous with the sequence number of the second message received last time; and
encapsulating a detailed topology response message according to a comparison result and returning the detailed topology response message to the ground network controller, wherein the detailed topology response message is used for indicating whether the ground network controller retransmits the transmitted detailed topology message;
and the over-top satellite node sends detailed topology messages which are successfully received to the neighbor satellite nodes connected with the over-top satellite node through the direct connection port, and the neighbor satellite nodes send detailed topology messages to other satellite nodes connected with the over-top satellite node.
Optionally, packaging the detailed topology response message according to the comparison result, specifically including:
if the first message sequence number is continuous with the second message sequence number, determining that the detailed topology message is successfully received, recording the first sequence number and packaging an error code field successfully received in the detailed topology response message;
If the first message sequence number is discontinuous with the second message sequence number, comparing the sizes of the first message sequence number and the second message sequence number;
and if the first message serial number is larger than the second message serial number, packaging an error code and the second message serial number in the detailed topology response message.
Optionally, 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 aiming at the topology version message, and specifically comprises the following steps:
the overhead satellite node judges whether the topology version message is successfully received according to the first version number and the locally stored second version number; and
and packaging corresponding error code fields in the topology version response message according to the judging result, and returning the topology version response message to the ground network controller, wherein the error code fields are used for representing successful transmission of the topology version message or transmission errors of the topology version message and types of errors when the transmission errors occur.
Optionally, the method further comprises:
receiving a link update message sent by a neighbor satellite node, wherein the link update message carries a link identifier and a third serial number;
Searching a fourth serial number of a corresponding link in a locally stored topology information table according to the link identifier;
comparing the third sequence number with the fourth sequence number, if the third sequence number is larger than the fourth sequence number, updating a local topology information table, returning a link update response message to the neighbor satellite node, forwarding the link update message to other neighbor satellite nodes through other ports except for receiving the link update message, and forwarding the link update message to other satellite nodes by other neighbor satellite nodes;
if the third sequence number is the same as the fourth sequence number, determining that the local link information is updated and returning a link update response message to the neighbor satellite node;
and if the third sequence number is smaller than the fourth sequence number, packaging corresponding link information according to the link identifier and returning a link update response message.
In a second aspect, the present disclosure further provides a method for managing a topology of an inter-satellite route of a low-orbit satellite, including:
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 packaged by the overhead satellite node according to the topology version number;
when the fact that a detailed topology message needs to be sent to the overhead satellite node is determined according to the topology version response message, the detailed topology message is sent to the overhead satellite node according to a locally generated topology information table, and the detailed topology message carries a first message serial number;
receiving a detailed topology response message returned by the overhead satellite node, wherein the detailed topology response message is packaged by the overhead satellite node according to the comparison result of the first message serial number and the locally stored second message serial number;
judging whether the detailed topology message needs to be retransmitted or not according to the detailed topology response message.
Optionally, the detailed topology response message carries an error code field and other serial number fields; and
and when the detailed topology message is sent to the overhead satellite node, the method further comprises the following steps:
adding the detailed topology message into a retransmission queue and starting a retransmission timer; and
judging whether the detailed topology message needs to be retransmitted or not according to the detailed topology response message, wherein the method specifically comprises the following steps:
If the detailed topology message is determined to be successfully transmitted according to the error code field, deleting the detailed topology message from the retransmission queue;
if the detailed topology message transmission errors are determined according to the error code fields, retransmitting the detailed topology message between the second message serial number and the first message serial number according to the second message serial numbers in the other serial number fields;
retransmitting the detailed topology message in the retransmission queue under the condition that the retransmission timer is exceeded; and
if the retransmission times are greater than a preset threshold, determining that the detailed topology message transmission with the retransmission times greater than the preset threshold fails.
In a third aspect, the present disclosure further provides a system for managing a topology of an inter-satellite route of a low-orbit satellite, including a ground network controller and satellite nodes, where the satellite nodes include overhead satellite nodes, the overhead satellite nodes communicate with the ground network controller through feeder links, and each satellite node communicates with each other through an inter-satellite link, where:
the ground network controller is configured to send a topology version message to the overhead satellite node, where the topology version message carries a topology version number; when the fact that a detailed topology message needs to be sent to the overhead satellite node is determined according to the topology version response message, the detailed topology message is sent to the overhead satellite node according to a locally generated topology information table, and the detailed topology message carries a first message serial number; judging whether the detailed topology message needs to be retransmitted or not according to the detailed topology response message;
The overhead satellite node is configured to return a topology version response message to the ground network controller according to the topology version message, where the topology version response message is encapsulated according to the topology version number; comparing whether the sequence number of the message received at this time is continuous with the sequence number of the second message received last time; packaging the detailed topology response message according to the comparison result and returning the detailed topology response message to the ground network controller; and sending detailed topology messages which are successfully received to the neighbor satellite nodes connected with the neighbor satellite nodes through the direct connection ports, and sending the detailed topology messages to other satellite nodes connected with the neighbor satellite nodes through the neighbor satellite nodes.
Optionally, the overhead satellite node is specifically configured to determine that the detailed topology message is successfully received if the first message sequence number is continuous with the second message sequence number, record the first sequence number, and encapsulate an error code field that is successfully received in the detailed topology response message; if the first message sequence number is discontinuous with the second message sequence number, comparing the sizes of the first message sequence number and the second message sequence number; and if the first message serial number is larger than the second message serial number, packaging an error code and the second message serial number in the detailed topology response message.
Optionally, the topology version message carries a first version number; the overhead satellite node is specifically configured to determine whether the topology version message is successfully received according to the first version number and the locally stored second version number; and packaging corresponding error code fields in the topology version response message according to the judging result and returning the topology version response message to the ground network controller, wherein the error code fields are used for representing the successful transmission of the topology version message or the transmission error of the topology version message and the type of the error when the transmission error occurs.
Optionally, the overhead satellite node is further configured to receive a link update packet sent by a neighboring satellite node, where the link update packet carries a link identifier and a third sequence number; searching a fourth serial number of a corresponding link in a locally stored topology information table according to the link identifier; comparing the third sequence number with the fourth sequence number, if the third sequence number is larger than the fourth sequence number, updating a local topology information table, returning a link update response message to the neighbor satellite node, forwarding the link update message to other neighbor satellite nodes through other ports except for receiving the link update message, and forwarding the link update message to other satellite nodes by other neighbor satellite nodes; if the third sequence number is the same as the fourth sequence number, determining that the local link information is updated and returning a link update response message to the neighbor satellite node; and if the third sequence number is smaller than the fourth sequence number, packaging corresponding link information according to the link identifier and returning a link update response message.
Optionally, the detailed topology response message carries an error code field and other serial number fields; the ground network controller is further used for adding the detailed topology message into a retransmission queue and starting a retransmission timer while sending the detailed topology message to the overhead satellite node; if the detailed topology message is determined to be successfully transmitted according to the error code field, deleting the detailed topology message from the retransmission queue; if the detailed topology message transmission errors are determined according to the error code fields, retransmitting the detailed topology message between the second message serial number and the first message serial number according to the second message serial numbers in the other serial number fields; retransmitting the detailed topology message in the retransmission queue under the condition that the retransmission timer is exceeded; and if the retransmission times are greater than a preset threshold, determining that the detailed topology message transmission with the retransmission times greater than the preset threshold fails.
The above-mentioned at least one technical scheme that this specification adopted can reach following beneficial effect:
in the embodiment of the invention, when a topology information table changes, a ground network controller firstly transmits a topology version message to a top-passing satellite node, the top-passing satellite node compares version information of a local topology information table through a response, and determines whether the topology version message needs to be retransmitted or not, and returns a response message to the ground network controller.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the present specification more apparent, the technical solutions of the present specification will be clearly and completely described below with reference to specific embodiments of the present specification and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present specification. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the present disclosure.
As described herein, the term "comprising" and its various modifications can be understood as open-ended terms, which mean "including, but not limited to," and the term "one embodiment" can be understood as "at least one embodiment.
The following describes in detail the technical solutions provided by the embodiments of the present specification with reference to the accompanying drawings.
Example 1
Fig. 1 is a schematic structural diagram of a low-orbit satellite inter-satellite routing topology management system according to an embodiment of the present invention. The low-orbit satellite inter-satellite routing topology management system provided by the embodiment of the invention comprises a ground network controller, an overhead satellite node and other satellite nodes, and for convenience of description, the satellite node directly connected with the overhead satellite node is called a neighbor satellite node. The surface network controller is connected with the satellite through a feed link, so that information interaction between the ground and satellite nodes is realized. Each satellite node and inter-satellite links form an inter-satellite network, so that cross-satellite cross-domain data transmission is realized. When the ground network controller sends the topology information table, the topology version message is adopted for forward broadcast detection, and the strategy of reliability transmission of the follow-up topology detailed message is adopted for carrying out loop-free whole-network flooding. When the link changes, the source satellite node generating the link update message sends the message to all the neighbor satellite nodes and the ground network controller, and the neighbor satellite nodes autonomously judge whether to continue flooding or not according to the serial numbers, send back a response message, and complete the whole network diffusion of the message reliably and without a loop.
It should be noted that, the flow of transmitting messages between the ground network controller and the overhead satellite node, between the overhead satellite node and its neighboring satellite node, and between the other satellite nodes is basically the same, and for convenience of description, in the embodiment of the present invention, the flow of transmitting messages between the ground network controller and the overhead satellite node is described as an example.
Optionally, unicast transmission data is arranged between the ground and the overhead satellite, loop prevention is not needed, broadcast transmission data is arranged between the overhead satellite and other satellites, other satellites judge whether follow-up detailed topology messages are needed according to serial numbers of version messages, one satellite can receive the same version of messages from different interfaces, a mechanism of the version of messages has loop prevention function, and the follow-up detailed messages are received by the interfaces received in advance.
Based on the low-orbit satellite inter-satellite routing topology management system shown in fig. 1, the embodiment of the invention provides a low-orbit satellite inter-satellite routing topology management method, and fig. 2 is a schematic flow chart of the low-orbit satellite inter-satellite routing topology management method provided in an embodiment of the present disclosure, where the method is executed by a central control or a processor of an overhead satellite node, referring to fig. 2, and the method specifically may include the following steps:
Step 102, the overhead satellite node receives the topology version message sent by the ground network controller.
In the implementation, after calculating the topology information table of the time slices, the ground network controller defines the topology version number and encapsulates the topology version number into a topology version message to be sent to the overhead satellite node. Specifically, the overhead satellite node comprises a satellite-ground topology information interaction module, a topology version message sent by a ground network controller is received through the satellite-ground topology information interaction module, and the topology version message carries a first version number.
Step 104, the overhead satellite node returns a topology version response message to the ground network controller aiming at the topology version message.
After receiving the topology version message, the overhead satellite node judges whether a subsequent detailed topology message is needed according to the version number carried in the topology version message, and replies a topology version response message to the ground network controller.
Specifically, the overhead satellite node compares a first version number of a topology information table carried in a topology version message with a second version number of a locally stored topology information table, determines that the topology information table is updated if the first version number is greater than the second version number, and encapsulates indication information of a topology version response message requiring detailed topology messages. 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. And the ground network controller judges whether the detailed topology message needs to be continuously transmitted according to the field value of the field.
When the method is implemented, after receiving the topology version message, the overhead satellite node forwards the topology version message to the neighbor satellite nodes directly connected with the overhead satellite node, and after receiving the detailed message, the overhead satellite node forwards the topology version message to other satellite nodes connected with the overhead satellite node. In specific implementation, topology version messages can be transmitted among other satellite nodes according to the following flow: for convenience in description in future, the satellite node sending the topology version message is called a sending end, the satellite node receiving the topology version message is called a receiving end, the sending end sends the topology version message received by the receiving end to the receiving end, the receiving end 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 is updated, and indication information of the topology message required to be detailed is packaged in a topology version response message returned to the sending end. If the first version number is the same as the third version number, the instruction receiving end has received the same topology version message, and the indication information of the detailed topology message is packaged in the returned topology version response message. If the first version number is smaller than the third version number, the returned topology version response message is packaged with indication information with small version number, the receiving end packages the topology abstract message and sends the topology abstract message to the sending end, and the topology information table of the sending end is tried to be updated.
It should be noted that, after the interaction between the ground and the satellite is completed, the forwarding between satellites is performed, and the transmission mode of the topology version message is broadcast transmission, that is, the overhead satellite node transmits the topology version message to all the direct-connected satellite nodes, and the non-overhead satellite node transmits the topology version message to the direct-connected satellite nodes from other ports except the receiving port; the topology detailed message is unicast sent by the sending end according to the topology version response message returned by the receiving end, that is, the sending end sends the detailed topology message to the receiving end needing the detailed topology message according to the indication information carried in the topology version response message returned by the receiving end.
In addition, the overhead satellite node can also judge whether the topology version message is successfully received according to the first version number and the locally stored second version number; and packaging corresponding error code fields in the topology version response message according to the judging result and returning the topology version response message to the ground network controller, wherein the error code fields are used for representing successful transmission of the topology version message or transmission errors of the topology version message and types of errors when the transmission errors occur, so that the ground network controller retransmits the topology version message according to the types of errors.
And 106, the over-the-top satellite node receives a detailed topology message sent by the ground network controller based on the topology version response message.
In this step, after receiving the topology version response message, the ground network controller sends the detailed topology message to the overhead satellite node if it is determined that the detailed topology message needs to be transmitted according to the indication information therein. In the embodiment of the invention, in order to ensure the reliability of information transmission, a serial number confirmation response mechanism is adopted to transmit a detailed topology message.
Specifically, the ground network controller carries a sequence number in the sent detailed topology message, the sequence numbers of the continuously sent detailed topology messages are continuous, and the ground network controller adds the sent detailed topology message into a message retransmission queue maintained locally while sending the detailed topology message.
And step 108, the overhead satellite node compares whether the sequence number of the first message received at this time is continuous with the sequence number of the second message received at last time, encapsulates the detailed topology response message according to the comparison result and returns the detailed topology response message to the ground network controller.
After receiving the detailed topology message, the overhead satellite node analyzes the message, and judges the processing method and whether the sequence number of the message needs to be recorded; if the sequence number in the message is continuous with the sequence number received last time, the receiving is considered to be successful, and the sequence number is recorded; if the sequence number is discontinuous with the last received sequence number, judging the size of the sequence number. If the received sequence number is smaller, the message is considered as a retransmission message, and the data is analyzed but the sequence number is not recorded; if the received sequence number is larger, the part of the message between the two sequence numbers is considered to be not successfully received, the last received sequence number is packaged into other sequence number fields of the detailed topology response message, the sending end is required to retransmit the sequence number message which is not received, and the sequence number is recorded; if the serial numbers are the same, the message is considered to be received and is not processed.
In one embodiment, the overhead satellite node compares whether the sequence number of the first message received this time is continuous with the sequence number of the second message received last time, encapsulates the detailed topology response message according to the error code of the comparison result mark and other sequence numbers, and sends the detailed topology response message to the ground network controller.
Specifically, if the sequence number of the first message is continuous with the sequence number of the second message, determining that the detailed topology message is successfully received, recording the first sequence number, and encapsulating an error code field successfully received in the detailed topology response message; if the first message sequence number is discontinuous with the second message sequence number, comparing the sizes of the first message sequence number and the second message sequence number; and if the first message sequence number is larger than the second message sequence number, packaging an error code and the second message sequence number in the detailed topology response message.
And 110, the over-top satellite node sends detailed topology messages which are successfully received to the neighbor satellite nodes connected with the over-top satellite node through the direct connection port, and the neighbor satellite nodes send the detailed topology messages to other satellite nodes connected with the over-top satellite node.
Similar to the flow of updating the topology information table between the ground network controller and the overhead satellite node, the overhead satellite node adopts the forward broadcast detection of the topology version message, judges whether the subsequent detailed topology message needs to be transmitted to the neighbor satellite node according to the version number carried in the topology version message, and if the subsequent detailed topology message needs to be transmitted, adopts a serial number confirmation response mechanism to continuously transmit the detailed topology message to the neighbor satellite node; and
And the neighbor satellite nodes adopt the topology version message to carry out broadcast detection, judge whether the follow-up detailed topology message to other satellite nodes connected with the neighbor satellite nodes is needed according to the version number carried in the topology version message, and if the follow-up detailed topology message is needed, continue to transmit the detailed topology message to the other satellite nodes by adopting a serial number confirmation response mechanism. Thus, the update of the topology information table among satellites is realized.
On the basis, the embodiment of the invention also provides a method for updating the topology information table caused by the link change between satellites. When any satellite node detects that the link connected with the satellite node changes, the link updating message can be sent to the satellite node directly connected with the satellite node, the satellite node receiving the link updating message forwards the link updating message to other satellite nodes connected with the satellite node, and the like, so that the whole network route updating is finally realized. In the embodiment of the invention, the flow of processing the link update message by the overhead satellite node is taken as an example for explanation. The over-top satellite node receives a link update message sent by a neighbor satellite node, wherein the link update message carries a link identifier and a third serial number; searching a fourth serial number of a corresponding link in a locally stored topology information table according to the link identification; comparing the third serial number with the fourth serial number, if the third serial number is larger than the fourth serial number, updating the local topology information table, returning a link update response message to the adjacent satellite node, forwarding the link update message to other adjacent satellite nodes through other ports except for receiving the link update message, and forwarding the link update message to other satellite nodes by other adjacent satellite nodes; if the third serial number is the same as the fourth serial number, determining that the local link information is updated and returning a link update response message to the neighbor satellite node; and if the third sequence number is smaller than the fourth sequence number, packaging corresponding link information according to the link identification and returning a link update response message.
It should be noted that, the flow of processing the link update message by other satellite nodes is the same as the flow of processing the link update message by the overhead satellite node, and will not be described here again.
Based on this, in this embodiment, each satellite node and inter-satellite links form an inter-satellite network to implement inter-satellite cross-domain data transmission, and when there is a link change, the source satellite node that generates the link update message sends the message to all neighboring satellite nodes and the ground network controller, and the neighboring satellite nodes autonomously determine whether to continue flooding according to the serial number, send back a response message, and complete the whole network flooding with reliable message and no loop.
Example two
Fig. 3 is a flow chart of a low-orbit satellite inter-satellite routing topology management method according to a second embodiment of the present disclosure, where the method specifically includes the following steps:
step 202, the ground network controller sends a topology version message to the overhead satellite node.
Wherein, the topology version message carries a topology version number.
It should be noted that, one implementation of step 202 may be:
the ground controller calculates a topology information table of the time slices, defines a version number, encapsulates the version number into a topology version message, and sends the topology version message to the overhead satellite node.
When the method is implemented, the detailed topology message is added into a retransmission queue and a retransmission timer is started while the detailed topology message is sent to the overhead satellite node; if the detailed topology message is successfully transmitted according to the error code field, deleting the detailed topology message from the retransmission queue; if the detailed topology message transmission error is determined according to the error code field, retransmitting the detailed topology message between the second message serial number and the first message serial number according to the second message serial numbers in other serial number fields; if the retransmission timer is exceeded, retransmitting the detailed topology message in the retransmission queue; if the retransmission times are greater than a preset threshold, determining that the detailed topology message transmission with the retransmission times greater than the preset threshold fails.
And 204, receiving a topology version response message returned by the overhead satellite node.
The topology version response message is encapsulated by the overhead satellite node according to the topology version number.
It should be noted that, one implementation of step 204 may be:
and the ground controller receives the topology version response message returned by the overhead satellite node, and the topology version response message is packaged and sent according to the topology version number after the overhead satellite node completes the version number judgment.
And 206, when the detailed topology message needs to be sent to the overhead satellite node according to the topology version response message, sending the detailed topology message to the overhead satellite node according to a locally generated topology information table.
The detailed topology message carries a first message serial number.
It should be noted that one implementation of step 206 may be:
and the ground network controller judges whether a detailed topology message needs to be sent to the overhead satellite node according to the topology version response message, and if so, a serial number confirmation response mechanism is adopted to send the detailed topology message to the overhead satellite node so as to ensure the reliability of information transmission.
And step 208, receiving a detailed topology response message returned by the overhead satellite node.
The detailed topology response message is packaged by the overhead satellite node according to the comparison result of the first message serial number and the locally stored second message serial number.
Step 210, judging whether the detailed topology message needs to be retransmitted according to the detailed topology response message.
It should be noted that, one implementation of step 210 may be:
The ground network controller deletes the corresponding message in the retransmission queue, judges whether the detailed topology message needs to be retransmitted according to the error code in the detailed topology response message, and determines the message sequence number needing to be retransmitted according to other sequence number fields in the detailed topology response message.
Based on this, in this embodiment, the ground network controller connects to the satellite through the feeder link to realize information interaction between the ground and the satellite node, and when the ground network controller sends the topology information table, the topology version message is adopted to broadcast and detect first, and then the loop-free whole network flooding is performed according to the policy topology detailed message of the reliability transmission.
Example III
Based on the low-orbit satellite inter-satellite routing topology management system shown in fig. 1:
the ground network controller is configured to send a topology version message to the overhead satellite node, where the topology version message carries a topology version number; when the fact that a detailed topology message needs to be sent to the overhead satellite node is determined according to the topology version response message, the detailed topology message is sent to the overhead satellite node according to a locally generated topology information table, and the detailed topology message carries a first message serial number; judging whether the detailed topology message needs to be retransmitted or not according to the detailed topology response message;
The overhead satellite node is configured to return a topology version response message to the ground network controller according to the topology version message, where the topology version response message is encapsulated according to the topology version number; comparing whether the sequence number of the message received at this time is continuous with the sequence number of the second message received last time; packaging the detailed topology response message according to the comparison result and returning the detailed topology response message to the ground network controller; and sending detailed topology messages which are successfully received to the neighbor satellite nodes connected with the neighbor satellite nodes through the direct connection ports, and sending the detailed topology messages to other satellite nodes connected with the neighbor satellite nodes through the neighbor satellite nodes.
Example IV
The fourth embodiment of the present disclosure provides a method for managing a topology of an inter-satellite route of a low-orbit satellite, where the method specifically includes the following steps:
step one, a ground controller calculates a topology information table of time slices, defines a version number and packages the version number into a topology version message to be sent to a satellite node; the satellite-ground topology information interaction module of the satellite node is responsible for interacting a topology information table: the satellite-to-ground topology information interaction module receives the topology version message and replies a topology version response message; to ensure reliability, a sequence number acknowledgement mechanism is used to receive detailed topology messages.
It should be noted that, in the first step, the version number judgment does not occur because the topology information of the satellite is uploaded by the ground network controller, and the ground network controller has the latest version number.
Step two, the inter-satellite topology information diffusion module is responsible for diffusing the received topology information to the whole network: adopting topology version message to carry out broadcast detection; judging whether a subsequent detailed topology message is needed according to the version number carried in the topology version message, and replying a topology version response message; if the detailed topology message is needed, a serial number confirmation response mechanism is adopted to continue to transmit the detailed topology message, and if the detailed topology message is not needed, the detailed topology message is not processed.
It should be noted that the sequence number acknowledgement mechanism in the first and second steps includes:
when a transmitting end transmits a detailed topology message, a sequence number field is carried, the sequence number of a message which is continuously transmitted is a continuous integer, and the transmitting end adds the message into a retransmission queue;
when receiving a detailed topology message, a receiving end judges a processing method and whether the sequence number of the message needs to be recorded or not; if the sequence number in the message is continuous with the sequence number received last time, the receiving is considered to be successful, and the sequence number is recorded; if the sequence number is discontinuous with the last received sequence number, judging the size of the sequence number; if the received sequence number is smaller, the message is considered to be a retransmission message, and the sequence number is not recorded; if the received sequence number is larger, the partial message between the two sequence numbers is considered to be not successfully received, the last received sequence number is packaged into other sequence number fields of the detailed topology response message, and the sequence number is recorded; if the serial numbers are the same, the message is considered to be received and is not processed;
The receiving end sends a detailed topology response message, wherein the message carries the serial number of the detailed topology message, and the error code and other serial numbers are marked according to the judgment result in the last step;
the sender receives the detailed topology response message, deletes the corresponding message in the retransmission queue, judges whether to retransmit according to the error code, and judges the message serial number needing to retransmit according to other serial number fields;
if the retransmission timer of the transmitting end is overtime, transmitting a message overtime in a retransmission queue; if the number of retransmissions exceeds 3, the transmission is considered to be failed.
Optionally, judging whether a subsequent detailed topology message is needed according to the version number carried in the topology version message, which specifically includes: comparing the version number carried in the message with the local version number, if the version number in the message is large, updating topology information carried in the message, and transmitting the subsequent detailed topology message; if the version numbers are the same, the same message is received; if the version number in the message is small, the topology information of the sending end is considered to be lagged, the topology version message of the receiving end is packaged and sent to the sending end, and the topology information of the sending end is updated.
Optionally, the topology version message is broadcast transmission, the overhead satellite node transmits the topology version message to all the direct-connected satellite nodes, and the non-overhead satellite node transmits the topology version message from other ports except the receiving port to the direct-connected satellite nodes; and the topology detailed message is unicast-transmitted according to the received topology version response message.
And step three, when inter-satellite link changes are caused by emergency, the inter-satellite link abnormal diffusion module generates and broadcasts a link update message, updates a topology information table of the whole network, feeds back the link changes to the ground network controller, and a source satellite node generating the link update message broadcasts the message from all ports.
And the link updating message carries a sequence number field for judging whether the link information is old or new.
Optionally, the inter-satellite link abnormal 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, analyzes the message and updates the local topology information table, replies a link update response message, and updates the message from other ports other than the receiving port generally Hong Lianlu; if the serial numbers are the same, replying a link update response message, and considering that other processing is not performed after the link update response message is received; if the sequence number in the message is smaller, the link information is packaged, a link update message is returned, and a topology information table of the opposite terminal is updated.
Optionally, when the link update message is sent, the message is added into a retransmission queue until a link update response message sent by the direct-connection satellite node is received or a link update message with a larger link serial number is received, and the message is deleted in the retransmission queue, otherwise, the link update message is retransmitted.
And step four, the ground network controller receives the link updating message and updates the local topology information table.
Based on the above, the embodiment completes the topology management of the low-orbit satellite inter-satellite routing, synchronizes the topology information table of the satellite node and the ground network controller, and realizes the two-stage control structure of the ground network controller and the satellite node: on one hand, the ground network controller can perform centralized control and management on the service and the network according to the topology information table, and on the other hand, the satellite node also reserves part of controller functions, can quickly converge and reroute when the topology changes, avoids service interruption, and improves the data transmission efficiency.
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 correct transmission of data, the ground network controller calculates and sends the topology information table to the satellite node, and at the same time, the satellite node autonomously maintains the constellation topology change and feeds back to the ground controller. The topology management module of the satellite node can maintain topology information of the whole network, becomes a base stone for calculating a routing table in an inter-satellite routing protocol, can adapt to the change of links in the network and perform quick rerouting, and realizes high-efficiency transmission of services.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.