Connectionless Inter-Satellite Routing Methods and Systems

Abstract

This invention provides a connectionless inter-satellite routing method and system, comprising: when a ground user terminal transmits data to another ground user terminal, adding the location information of the receiver and sender and the data packet status information to the header; the satellite statistically analyzes its own inter-satellite port status and its own position coordinates, and finds a suitable port for the data packet to be sent; if no suitable port meets the preset conditions, the data packet is returned and retransmitted to the original address; if there is no destination address that meets the preset conditions, it is determined whether the satellite is the satellite accessed by the receiver; if so, the location information is removed and sent to the data packet receiver; otherwise, the data packet is broadcast; if the data packet still cannot find a receiver after broadcasting, the data packet is discarded. This invention reduces the difficulty of addressing and topology maintenance, makes full use of satellite port resources, improves the reliability of routing, makes port status feedback faster, and improves the accuracy of port status judgment.

Description

Technical Field

[0001] This invention relates to the field of satellite routing technology, and more specifically, to a method and system for inter-satellite routing in a connectionless manner. Background Technology

[0002] In recent years, due to the increasing demand for wide-area satellite communication capacity and the gradual depletion of available frequency bands, low-Earth orbit (LEO) internet satellite constellation systems have gradually come to the forefront. LEO satellite communication constellations are experiencing a new wave of construction worldwide. Utilizing LEO communication satellite constellations to form a globally seamless integrated information network to meet the high-capacity, wide-coverage, and high-quality service requirements of wireless networks and various user services has become a research hotspot and an important direction for the future development of wireless communication.

[0003] While low-Earth orbit (LEO) satellites offer advantages such as improved frequency utilization and communication speeds due to their low altitude and short orbital periods, the topology of the communication system connecting LEO satellite constellations and ground users changes rapidly, resulting in long regression cycles. This makes satellite routing and addressing exceptionally difficult. Compared to other algorithms, this algorithm leverages the relatively fixed locations of ground users, using the satellite's physical characteristics rather than logical identifiers for addressing. This simplifies network topology maintenance and facilitates data packet addressing.

[0004] Chinese patent document CN107787023A discloses a method and apparatus for generating low-Earth orbit satellite routes in an integrated space-ground network. The method includes: a target satellite acquiring a link status database corresponding to its current orbital position, the link status database including the topology of a network formed by links between satellites via ports; the target satellite detecting the connectivity status of the links it forms at a first preset period, and updating the connectivity identifiers of the ports corresponding to the links in a network-wide port connectivity identifier table based on the detection results, the network-wide port connectivity identifier table including the connectivity identifiers of each port of each satellite in the network, the connectivity identifier of each port corresponding to the connectivity status of the link formed by that port, the connectivity identifier including: normal and fault; the target satellite determining the connectivity status of the link formed by the port corresponding to the connectivity identifier through the connectivity identifiers of each port in the network-wide port connectivity identifier table, and correcting the topology of the link corresponding to that link in the link status database based on the connectivity status of that link; and the target satellite determining a routing table using a preset routing algorithm based on the corrected link status database.

[0005] Chinese patent document CN107787023A discloses a satellite routing algorithm under strong link constraints, including a route establishment and maintenance phase and a route forwarding phase. In the route establishment and maintenance phase, each satellite periodically sends probe packets to neighboring nodes based on the periodicity of satellite operation and the regularity of network topology to obtain the geographical location information of neighboring satellites, establish a neighbor table for satellite nodes, and preliminarily calculate and generate a multipath routing table based on the information in the neighbor table. This phase runs through the entire operation of the satellite network. In the route forwarding phase, satellite nodes estimate the transmission delay cost of each path under this state and select the link with the minimum transmission delay cost for forwarding.

[0006] Chinese patent document CN107787023A discloses a distributed node adaptive routing algorithm for LEO satellite networks. Its technical features are: constructing a grid-like LEO satellite communication system similar to an Iridium constellation; designing inter-satellite links along latitude and longitude lines, utilizing the mesh topology of the satellite constellation, with each satellite node independently responsible for forwarding data packets in the queue; and adding and transmitting additional network status information in the data packets to enable satellite nodes to perceive and predict the network status in different routing directions, thereby guiding the selection of outgoing links for the data packets.

[0007] Patent document CN106656302A (application number: CN201610843537.3) discloses a distributed node adaptive routing algorithm for LEO satellite networks. Its technical features are: constructing a grid-like LEO satellite communication system similar to an Iridium constellation; designing inter-satellite links along latitude and longitude lines, utilizing the mesh topology of the satellite constellation, with each satellite node independently responsible for forwarding data packets in the queue; and adding and transmitting additional network state information in the data packets to enable satellite nodes to perceive and predict the network state in different routing directions, thereby guiding the selection of outgoing links for the data packets. Summary of the Invention

[0008] In view of the deficiencies in the prior art, the purpose of this invention is to provide a method and system for inter-satellite routing in a connectionless manner.

[0009] The connectionless inter-satellite routing method provided by the present invention includes:

[0010] When a ground user terminal transmits data to another ground user terminal via a satellite constellation, the satellite constellation connected to the sender first uses the receiver's IP address to add the location information of the receiver and the sender and the data packet status information to the header.

[0011] The satellite collects information on its own inter-satellite port status and its own position coordinates, and finds a suitable port for the data packet to be sent. If no suitable port meets the preset conditions, the data packet is returned and resent to the original address.

[0012] If no destination address matching the preset conditions is found, it is determined whether the satellite is the satellite the receiver is accessing. If so, the location information is removed and sent to the data packet receiver; otherwise, the data packet is marked as broadcast mode and broadcast, and the satellite is judged. If the receiver is still not found after the data packet is broadcast, the data packet is discarded.

[0013] Preferably, the method of adding location information includes: after the satellite receives the IP packet from the ground user, it compares the IP address stored locally with the coordinate information of the ground user based on the IP address of the ground user in the header. After the satellite makes a table lookup comparison, it adds the location coordinates of the receiver and the transmitter to the header of the data packet and then adds check information to the tail.

[0014] The methods for adding status information include: data packets are divided into four states, namely sent, bounced, broadcast once, and broadcast twice, occupying 2 bits; after the location information is added to the header, another 2 bits of data packet status information are added to the header; the ratio of data packets in the sent state to data packets in the bounced state on each port is collected by satellite and used as satellite port status information.

[0015] Preferably, a suitable port is planned for sending data packets, including:

[0016] The satellite reads its own latitude and longitude information and calculates it with the coordinates of the sender and receiver. If the angle between the port and the direction of the receiving destination address is closer and the directional angle between the sender's position and the receiver's address is greater than 90 degrees, then the port is considered suitable; otherwise, it is considered unsuitable.

[0017] If a data packet is marked as being sent, the ports other than the source port of the data packet are sorted according to the angle size. Then, the status of the satellite ports is judged in turn. If the status of the port meets the threshold, the data packet is marked as being sent, and the port is selected to transmit the data packet.

[0018] If a data packet is marked as bounced, then the data packet is marked as sent, and then the port with the smallest angle after the bounced port is found and sent.

[0019] Preferably, returning the data packet to the original address for retransmission includes:

[0020] Returned packets have higher priority than sent packets. If a packet is marked as sent, the packet mark is changed to return, and the packet is returned from the source port.

[0021] If a data packet is marked as returned, the port with the smallest angle to the sending address is found to return the data packet.

[0022] Preferably, the satellite reads the IP address of the data packet receiver and determines whether the IP address is associated with the satellite. If so, it determines that the satellite is the satellite that the receiver has accessed.

[0023] If a data packet is marked as sent, then the data packet is marked as broadcast 1 and sent to all ports;

[0024] If a data packet is marked as broadcast 1, then mark the data packet as broadcast 2 and send it to all ports;

[0025] If the satellite receives a data packet marked as Broadcast 2 but still cannot find the corresponding ground user, it will discard the data packet.

[0026] The connectionless inter-satellite routing system provided by the present invention includes: a ground user terminal and a satellite constellation;

[0027] When a ground user terminal transmits data to another ground user terminal via a satellite constellation, the satellite constellation connected to the sender first uses the receiver's IP address to add the location information of the receiver and the sender and the data packet status information to the header.

[0028] The satellite collects information on its own inter-satellite port status and its own position coordinates, and finds a suitable port for the data packet to be sent. If no suitable port meets the preset conditions, the data packet is returned and resent to the original address.

[0029] If no destination address matching the preset conditions is found, it is determined whether the satellite is the satellite the receiver is accessing. If so, the location information is removed and sent to the data packet receiver; otherwise, the data packet is marked as broadcast mode and broadcast, and the satellite is judged. If the receiver is still not found after the data packet is broadcast, the data packet is discarded.

[0030] Preferably, the method of adding location information includes: after the satellite receives the IP packet from the ground user, it compares the IP address stored locally with the coordinate information of the ground user based on the IP address of the ground user in the header. After the satellite makes a table lookup comparison, it adds the location coordinates of the receiver and the transmitter to the header of the data packet and then adds check information to the tail.

[0031] The methods for adding status information include: data packets are divided into four states, namely sent, bounced, broadcast once, and broadcast twice, occupying 2 bits; after the location information is added to the header, another 2 bits of data packet status information are added to the header; the ratio of data packets in the sent state to data packets in the bounced state on each port is collected by satellite and used as satellite port status information.

[0032] Preferably, a suitable port is planned for sending data packets, including:

[0033] The satellite reads its own latitude and longitude information and calculates it with the coordinates of the sender and receiver. If the angle between the port and the direction of the receiving destination address is closer and the directional angle between the sender's position and the receiver's address is greater than 90 degrees, then the port is considered suitable; otherwise, it is considered unsuitable.

[0034] If a data packet is marked as being sent, the ports other than the source port of the data packet are sorted according to the angle size. Then, the status of the satellite ports is judged in turn. If the status of the port meets the threshold, the data packet is marked as being sent, and the port is selected to transmit the data packet.

[0035] If a data packet is marked as bounced, then the data packet is marked as sent, and then the port with the smallest angle after the bounced port is found and sent.

[0036] Preferably, returning the data packet to the original address for retransmission includes:

[0037] Returned packets have higher priority than sent packets. If a packet is marked as sent, the packet mark is changed to return, and the packet is returned from the source port.

[0038] If a data packet is marked as returned, the port with the smallest angle to the sending address is found to return the data packet.

[0039] Preferably, the satellite reads the IP address of the data packet receiver and determines whether the IP address is associated with the satellite. If so, it determines that the satellite is the satellite that the receiver has accessed.

[0040] If a data packet is marked as sent, then the data packet is marked as broadcast 1 and sent to all ports;

[0041] If a data packet is marked as broadcast 1, then mark the data packet as broadcast 2 and send it to all ports;

[0042] If the satellite receives a data packet marked as Broadcast 2 but still cannot find the corresponding ground user, it will discard the data packet.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) This invention uses port status to determine the behavior of each hop of the data packet, which makes fuller use of satellite port resources and improves the reliability of routing;

[0045] (2) The present invention uses statistical information of data packets to determine the port status, which makes the port status feedback faster and improves the accuracy of port status judgment. Attached Figure Description

[0046] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0047] Figure 1 This is a schematic diagram of the inter-satellite routing algorithm scenario for connectionless systems according to the present invention;

[0048] Figure 2 This is a flowchart of the connectionless inter-satellite routing algorithm of the present invention;

[0049] Figure 3 This is a schematic diagram illustrating the initial state of the connectionless inter-satellite routing algorithm of this invention.

[0050] Figure 4 This invention aims to provide a connectionless inter-satellite routing algorithm. Detailed Implementation

[0051] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0052] Example:

[0053] This invention addresses the current situation where satellite topology changes drastically, requiring satellites to frequently maintain inter-satellite and satellite-to-ground topology relationships. It leverages the fact that ground users move relatively slowly relative to satellites, calculates candidate routing paths using ground user location information, determines port status using data packet statistics, further uses port status to determine the behavior of each hop of the data packet, and finally performs data packet routing.

[0054] like Figure 1 This is a schematic diagram of an inter-satellite routing algorithm for a connectionless scenario. The present invention provides an inter-satellite routing algorithm for a connectionless scenario, such as... Figure 2 It includes the following steps:

[0055] When a ground user terminal transmits data to another ground user terminal via a satellite constellation, the satellite constellation connected to the sender first uses the receiver's IP address to add the location information of both the receiver and the sender, as well as the data packet status information, to the header. The satellite then calculates its own inter-satellite port status and its own position coordinates, and finds a suitable port for the data packet to send. If no suitable port meets the requirements, the data packet is returned and retransmitted to the original address. If no suitable destination address is found, it is determined whether the satellite is the one the receiver has accessed. If so, the location information is removed and the data packet is sent to the data packet receiver. Otherwise, the data packet is marked as broadcast and broadcast, and the satellite performs an on-board assessment. If the data packet still cannot find a receiver after broadcasting, the data packet is discarded.

[0056] The method of adding location information includes the following steps: After receiving the IP packet from the ground user, the satellite compares the IP address stored locally with the coordinate information of the ground user based on the IP address of the ground user in the header; after comparing according to the lookup table, the satellite adds the location coordinates of the receiver and the transmitter to the header of the data packet, and then adds check information to the tail.

[0057] The method for adding status information includes the following steps: There are four states for data packets: sent, returned, broadcast once, and broadcast twice, each occupying 2 bits; after adding the location information to the header, 2 bits of data packet status information are added to the header.

[0058] The acquisition of inter-satellite port status includes the following steps: The satellite collects the ratio of data packets transmitting status to data packets returning status on each port as satellite port status information.

[0059] Planning a suitable port for data packet transmission involves the following steps: The satellite reads its own latitude and longitude information and calculates it with the coordinates of the sender and receiver. If the angle between the port and the direction of the destination address is closer, and the directional angle between the sender's location and the receiver's address is greater than 90 degrees, then the port is considered suitable; otherwise, it is considered unsuitable. If the data packet is marked for transmission, the ports other than the source port are sorted according to the angle. Then, the satellite port status is checked in turn. If the port status meets the threshold, the data packet is marked for transmission, and the port is selected to transmit the data packet. If the data packet is marked for rejection, the data packet is marked for transmission, and then the port with the smallest angle after the rejection port is found for transmission.

[0060] Returning a data packet to its original address and retransmitting it involves the following steps: returning the packet has a higher priority than sending the packet; if the packet is marked as sent, change the packet marking to return and return the packet from the source port; if the packet is marked as returned, find the port with the smallest angle to the sending address and return the packet.

[0061] Determining whether a satellite is the one the receiver is accessing involves the following steps: The satellite reads the receiver's IP address from the data packet and determines whether the IP address is associated with the satellite. If so, the satellite is the one the receiver is accessing.

[0062] The process of marking a data packet as broadcast mode includes the following steps: if the data packet is marked as send, then the data packet is marked as broadcast 1 and sent to all ports; if the data packet is marked as broadcast 1, then the data packet is marked as broadcast 2 and sent to all ports.

[0063] If no recipient is found after the data packet is broadcast, the following steps are taken: If the satellite still cannot find the corresponding access ground user after receiving the data packet marked as broadcast 2, the data packet is discarded.

[0064] like Figure 3 Ground user terminal A and ground user terminal B are located at two different ground locations. Satellites 1 to 5 form a satellite constellation between user terminals A and B, and the satellites are interconnected to form an inter-satellite topology network.

[0065] The data packet is uploaded from user terminal A to satellite 1 and then sent to user terminal B. Satellite 1 adds the latitude and longitude coordinates of user terminal A and user terminal B to the header of the data packet, adds a checksum to the tail, and then adds a status message to the header.

[0066] The message return rate of port a of satellite 1 did not exceed the threshold and the status was normal. The angle between the direction angle of port a and the direction angle of the destination address was the smallest and smaller than the angle between the direction angle of the starting address. The direction angle between the sender's position and the receiver's address was greater than 90 degrees. Therefore, the message was sent to satellite 2 via port a.

[0067] Satellite 2 works similarly to Satellite 1, sending the message from port a to Satellite 3.

[0068] When port C of satellite 3 receives a data packet, calculations show that the angles between the direction angles of ports A and B of satellite 3 and the direction angle of the destination address are smaller than the angles between the direction angles of the starting address and the destination address. However, the packet return rate of both ports exceeds the threshold. Therefore, the packet status flag is changed to "returned," and the packet is retransmitted to satellite 2 by port C of satellite 3.

[0069] Satellite 2 receives a data packet marked as a return message from Satellite 3 via port a. Satellite 2 selects port b, whose azimuth angle is second only to port a, modifies the header status to transmit, and sends it to Satellite 4.

[0070] Satellite 4 works similarly to Satellite 1, sending messages from port a to Satellite 5.

[0071] Due to transmission delays, the connection relationships of user terminals have changed, such as... Figure 4 As shown, the user terminal is connected to satellite 7, but since its geographical location has not changed significantly, the message information does not need to be modified and addressing can continue.

[0072] Satellite 5 works similarly to Satellite 1, sending messages from port a to Satellite 6.

[0073] Because the azimuth angle between the sender's location and the receiver's address is less than 90 degrees, satellite 6 does not have a suitable inter-satellite destination port. Satellite 6 reads its own user access data and finds that user terminal B is not connected to satellite 6. Therefore, satellite 6 changes the data packet status word to broadcast 1 and broadcasts it to satellites 5, 7, and 8.

[0074] After receiving the broadcast message, Satellite 5 reads its own user access data and finds that user terminal B has not connected to Satellite 5. Therefore, Satellite 5 changes the status word of the data packet to broadcast 2 and broadcasts it to Satellite 4.

[0075] After receiving the broadcast message, Satellite 4 reads its own user access data and finds that user terminal B has not connected to Satellite 4. Therefore, Satellite 4 directly discards the data packet.

[0076] After receiving the broadcast message, Satellite 7 reads its own user access data and finds that User Terminal B has connected to Satellite 7. Therefore, Satellite 7 removes the header address and status information and the packet tail checksum information and sends the data packet to User Terminal B. Transmission ends.

[0077] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0078] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A connectionless inter-satellite routing method, characterized in that, include: When a ground user terminal transmits data to another ground user terminal via a satellite constellation, the satellite connected to the sender first uses the receiver's IP address to add the location information of the receiver and the sender, as well as the data packet status information, to the header; the data packet statuses are sent, returned, broadcast once, and broadcast twice. The satellite collects statistics on its own inter-satellite port status and its own position coordinates. The satellite collects the ratio of data packets in the sending state to data packets in the returning state on each port as satellite port status information, and finds a suitable port for the data packets to be sent. If a suitable port exists, it determines whether the return ratio of the suitable port meets the preset conditions. If not, the data packets are returned and resent to the original address. If no suitable port is found, it is determined whether the satellite is the satellite that the receiver is connected to. If so, the location information is removed and sent to the data packet receiver; otherwise, the data packet is marked as broadcast mode and broadcast, and the satellite is judged. If the receiver is still not found after the data packet is broadcast, the data packet is discarded.

2. The inter-satellite routing method for connectionless systems according to claim 1, characterized in that, The method of adding location information includes: after the satellite receives the IP packet from the ground user, it compares the IP address stored locally with the coordinate information of the ground user based on the IP address of the ground user in the header. After the satellite makes a table lookup comparison, it adds the location coordinates of the receiver and the transmitter to the header of the data packet and then adds check information to the tail. The method of adding status information occupies 2 bits; after the location information is added to the header, another 2 bits of data packet status information are added to the header.

3. The inter-satellite routing method for connectionless systems according to claim 1, characterized in that, Find a suitable port for sending the data packet, including: The satellite reads its own latitude and longitude information and calculates it with the coordinates of the sender and receiver. If the angle between the port and the direction of the receiving destination address is closer and the directional angle between the sender's position and the receiver's address is greater than 90 degrees, then the port is considered suitable; otherwise, it is considered unsuitable. If a data packet is marked as being sent, the ports other than the source port of the data packet are sorted according to the angle size. Then, the status of the satellite ports is judged in turn. If the status of the port meets the threshold, the data packet is marked as being sent, and the port is selected to transmit the data packet. If a data packet is marked as bounced, then the data packet is marked as sent, and then the port with the smallest angle after the bounced port is found and sent.

4. The connectionless inter-satellite routing method according to claim 1, characterized in that, Returning the data packet to the original address for retransmission includes: Returned packets have higher priority than sent packets. If a packet is marked as sent, the packet mark is changed to return, and the packet is returned from the source port. If a data packet is marked as bounced, find the port with the smallest angle to the sending address and bounce the data packet.

5. The inter-satellite routing method for connectionless systems according to claim 1, characterized in that, The satellite reads the IP address of the data packet receiver and determines whether the IP address is associated with the satellite. If so, it determines that the satellite is the one the receiver is connected to. If a data packet is marked as sent, then the data packet is marked as broadcast 1 and sent to all ports; If a data packet is marked as broadcast 1, then mark the data packet as broadcast 2 and send it to all ports; If the satellite receives a data packet marked as Broadcast 2 but still cannot find the corresponding ground user, it will discard the data packet.

6. A connectionless inter-satellite routing system, characterized in that, include: Ground user terminals and satellite constellations; When a ground user terminal transmits data to another ground user terminal via a satellite constellation, the satellite connected to the sender first uses the receiver's IP address to add the location information of the receiver and the sender, as well as the data packet status information, to the header; the data packet statuses are sent, returned, broadcast once, and broadcast twice. The satellite collects statistics on its own inter-satellite port status and its own position coordinates. The satellite collects the ratio of data packets in the sending state to data packets in the returning state on each port as satellite port status information, and finds a suitable port for the data packets to be sent. If a suitable port exists, it determines whether the return ratio of the suitable port meets the preset conditions. If not, the data packets are returned and resent to the original address. If no suitable port is found, it is determined whether the satellite is the satellite that the receiver is connected to. If so, the location information is removed and sent to the data packet receiver; otherwise, the data packet is marked as broadcast mode and broadcast, and the satellite is judged. If the receiver is still not found after the data packet is broadcast, the data packet is discarded.

7. The connectionless inter-satellite routing system according to claim 6, characterized in that, The method of adding location information includes: after the satellite receives the IP packet from the ground user, it compares the IP address stored locally with the coordinate information of the ground user based on the IP address of the ground user in the header. After the satellite makes a table lookup comparison, it adds the location coordinates of the receiver and the transmitter to the header of the data packet and then adds check information to the tail. The method of adding status information occupies 2 bits; after the location information is added to the header, another 2 bits of data packet status information are added to the header.

8. The connectionless inter-satellite routing system according to claim 6, characterized in that, Find a suitable port for sending the data packet, including: The satellite reads its own latitude and longitude information and calculates it with the coordinates of the sender and receiver. If the angle between the port and the direction of the receiving destination address is closer and the directional angle between the sender's position and the receiver's address is greater than 90 degrees, then the port is considered suitable; otherwise, it is considered unsuitable. If a data packet is marked as being sent, the ports other than the source port of the data packet are sorted according to the angle size. Then, the status of the satellite ports is judged in turn. If the status of the port meets the threshold, the data packet is marked as being sent, and the port is selected to transmit the data packet. If a data packet is marked as bounced, then the data packet is marked as sent, and then the port with the smallest angle after the bounced port is found and sent.

9. The connectionless inter-satellite routing system according to claim 6, characterized in that, Returning the data packet to the original address for retransmission includes: Returned packets have higher priority than sent packets. If a packet is marked as sent, the packet mark is changed to return, and the packet is returned from the source port. If a data packet is marked as bounced, find the port with the smallest angle to the sending address and bounce the data packet.

10. The connectionless inter-satellite routing system according to claim 6, characterized in that, The satellite reads the IP address of the data packet receiver and determines whether the IP address is associated with the satellite. If so, it determines that the satellite is the one the receiver is connected to. If a data packet is marked as sent, then the data packet is marked as broadcast 1 and sent to all ports; If a data packet is marked as broadcast 1, then mark the data packet as broadcast 2 and send it to all ports; If the satellite receives a data packet marked as Broadcast 2 but still cannot find the corresponding ground user, it will discard the data packet.

Images