A cross-domain routing system suitable for periodic landing handover of IGSO constellations

Abstract

The present invention relates to a cross-domain routing system suitable for periodic landing handover of an IGSO constellation, belonging to the field of satellite communication technology. Through designs such as on-board layer-2 switching, wide-area networking between stations, routing controlled diffusion, and double-layer routing addressing, the present invention realizes routing interconnection and service intercommunication between an IGSO satellite communication network and a terrestrial network. The present invention can be applied to scenarios where IGSO satellite users land through a gateway station and have service intercommunication with terrestrial network users, capable of improving the stability of system routing, reducing routing interaction overhead, and simultaneously achieving the purpose of seamless handover of IGSO satellite users to the landing gateway station.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite communication, and particularly to a cross-domain routing system suitable for periodic landing handover of an IGSO constellation. Background Art

[0002] GEO communication satellites are located in the equatorial plane and it is difficult to cover the polar regions. Since the orbit of an IGSO satellite has a certain inclination angle, it can provide long-term coverage for the polar regions and has unique advantages in supporting satellite communication for polar users. The IGSO has the same orbital altitude as the GEO, and its sub-satellite point trajectory on the ground is an "8" shape with the equator as the axis of symmetry. The coverage of a single IGSO satellite may not be as good as that of a single GEO satellite, but through the collaborative work of multiple IGSO satellites, continuous coverage of the polar regions can be achieved. With the growth of communication requirements such as polar scientific research and meteorological monitoring, there is an urgent need to build a satellite communication system with IGSO satellites as communication nodes, including polar users and in-country ground users.

[0003] When traditional GEO satellite networks are interconnected with ground networks, routing redistribution technology is usually adopted at the gateway station to mutually spread cross-domain routing information and realize service intercommunication between satellite network users and ground network users. Due to the periodic movement of IGSO satellites, a single IGSO satellite cannot maintain a normal connection with the gateway station, and multiple gateway stations need to be combined to achieve uninterrupted landing of the IGSO constellation. Due to the periodic change of the satellite network topology, it will trigger cross-domain routing updates of multiple gateway stations, which is likely to cause routing loops or non-optimal routes. In addition, during the routing update period, normal service communication will also be affected. Summary of the Invention

[0004] In view of this, the present invention proposes a cross-domain routing system suitable for periodic landing handover of an IGSO constellation. The present invention can realize service intercommunication between IGSO satellite network users and ground network users, and solve the problem of seamless handover of user terminals to landing gateway stations under the condition of periodic operation of IGSO.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A cross-domain routing system suitable for periodic landing handover of an IGSO constellation includes a satellite routing device, a ground routing device, a user routing device, a POP site, a CPE device, and a wide-area controller. Among them, the satellite routing device is deployed at an IGSO satellite node, the ground routing device and the POP site are deployed at the gateway station, the user routing device is deployed at the user terminal, the CPE device is deployed at the edge of the ground bearer network user, and the wide-area controller is co-located with any POP site; the routing information between IGSO satellite users and ground network users is diffusely controlled by the wide-area controller, and the service information is forwarded on demand through the POP site;

[0007] The satellite routing device runs the OSPF routing protocol, sets the satellite identifier as the IP address of the LoopBack interface. After route convergence, it generates an inter-satellite forwarding table indexed by the satellite identifier.

[0008] The ground routing device calculates the availability of the feeder link of the current gateway station according to the IGSO satellite ephemeris information. If it is available, it periodically sends the satellite identifier mapping information of the landing gateway station to the satellite routing device. Otherwise, it stops sending the satellite identifier mapping information. The satellite routing device receives the satellite identifier mapping information of the landing gateway station and generates a layer-2 mapping table indexed by the terminal identifier.

[0009] The user routing device runs the RIP routing protocol, obtains the satellite user reachable network segment information, generates a RIP packet including the satellite user reachable network segment, satellite identifier, and terminal identifier, and sends it to the satellite node. After receiving the RIP packet, the satellite routing device generates a layer-2 forwarding table indexed by the terminal identifier, encapsulates the information of the satellite identifier and terminal identifier of the landing gateway station, looks up the inter-satellite forwarding table, and forwards it to the ground routing device of the landing gateway station.

[0010] After receiving the RIP packet, the ground routing device generates a user identifier mapping table. The ground routing device runs the OSPF routing protocol and spreads the satellite user network routing information to the wide area controller. The wide area controller runs the OSPF routing protocol and spreads the satellite user network routing information to all CPE devices.

[0011] After the CPE device is started, it automatically connects to the affiliated POP site. The CPE device runs the OSPF routing protocol, obtains the ground user reachable network segment information, and spreads the ground user network routing information to the wide area controller. The wide area controller selects the landing gateway station and sends the ground user network routing information to the ground routing device of the landing gateway station through the OSPF protocol packet.

[0012] After receiving the ground user network routing information, the ground routing device generates a RIP packet including the ground user reachable network segment and virtual terminal identifier, and sends it to the satellite node. After receiving the RIP packet, the satellite routing device broadcasts it to other satellite nodes and broadcasts it to all user terminals under this satellite. The user routing device receives the RIP packet and generates a user identifier mapping table.

[0013] Further, when an IGSO satellite user accesses a terrestrial network user, the user routing device receives an IP data packet, looks up the user identification mapping table according to the destination IP address, and obtains the virtual terminal identification information of the landing gateway station; the user routing device encapsulates the virtual terminal identification in the IP data packet and sends it to the satellite node; the satellite routing device looks up the layer-2 mapping table according to the virtual terminal identification in the IP data packet to obtain the terminal identification and satellite identification information of the landing gateway station; the satellite routing device encapsulates the satellite identification and terminal identification in the IP data packet, and looks up the inter-satellite forwarding table to forward it hop by hop to the landing gateway station; the terrestrial routing device determines the terminal identification in the IP data packet, and if it is the same as this station, restores the original IP data packet and forwards it to the POP site; the POP site encapsulates the IP data packet in a bearer network IP tunnel and sends it to the CPE device; the CPE device restores the original IP data packet and forwards it to the service terminal.

[0014] Further, when a terrestrial network user accesses an IGSO satellite user, the CPE device receives an IP data packet, encapsulates it in a bearer network IP tunnel and sends it to the home POP site; the home POP site determines whether the current gateway station is a landing gateway station, and if so, forwards it to the terrestrial routing device, otherwise, encapsulates it in a bearer network IP tunnel and sends it to the POP site of the landing gateway station; after receiving the IP data packet, the terrestrial routing device looks up the user identification mapping table to obtain the satellite identification and terminal identification information of the user terminal; the terrestrial routing device encapsulates the satellite identification and terminal identification in the IP data packet and sends it to the satellite node; the satellite routing device looks up the inter-satellite forwarding table according to the satellite identification in the IP data packet to forward it hop by hop to the user terminal; after receiving the IP data packet, the user terminal determines the terminal identification in the IP data packet, and if it is the same as this user terminal, forwards the IP data packet to the service terminal, otherwise, discards the IP data packet.

[0015] Further, the layer-2 mapping table includes the information of the terminal identification and satellite identification of the landing gateway station.

[0016] Further, the terrestrial routing device and the wide area controller are set to the same network segment, and the OSPF protocol packet sent by the terrestrial routing device is intercepted by the POP site and sent to the wide area network controller after being encapsulated in a bearer network IP tunnel.

[0017] Further, the wide area controller selects the landing gateway station and sends the terrestrial user network routing information to the terrestrial routing device of the landing gateway station through the OSPF protocol packet. The specific method is: the wide area controller encapsulates the OSPF packet in a bearer network IP tunnel and sends it to the POP site, and the POP site restores the OSPF packet and sends it to the terrestrial routing device.

[0018] The present invention has the following beneficial effects compared with the background technology:

[0019] 1. The present invention can effectively reduce the number of interactions of cross - domain routing information. For the IGSO constellation handover landing gateway station, only the landing gateway station information of the satellite node is updated, and the routing information of the user terminal remains unchanged.

[0020] 2. The present invention can realize seamless handover of the service transmission path between IGSO satellite users and terrestrial network users among multiple gateway stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the application scenario of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0023] A cross - domain routing system suitable for periodic landing handover of the IGSO constellation Figure 1 For the application scenario of this system, the system can be specifically divided into: satellite routing equipment, terrestrial routing equipment, user routing equipment, POP site, CPE equipment, and wide - area controller. Among them:

[0024] The satellite routing equipment runs the OSPF routing protocol, sets the satellite identifier as the LoopBack interface IP address. After routing convergence, an inter - satellite forwarding table indexed by the satellite identifier is generated. The terrestrial routing equipment calculates the availability of the feeder link of the current gateway station according to the IGSO ephemeris information. If it is available, it periodically sends the satellite identifier mapping information of the landing gateway station to the satellite routing equipment. Otherwise, it stops sending the satellite identifier mapping information. The satellite routing equipment receives the satellite identifier mapping information of the landing gateway station and generates a two - layer mapping table indexed by the terminal identifier. The two - layer mapping table includes information such as the terminal identifier and satellite identifier of the landing gateway station.

[0025] After the user terminal accesses the network, it obtains the satellite identifier of the current satellite node. The user routing equipment runs the RIP routing protocol, obtains the satellite user reachable network segment information, generates a RIP message including the satellite user reachable network segment, satellite identifier, and terminal identifier, and sends it to the satellite node. After receiving the RIP message, the satellite routing equipment generates a two - layer forwarding table indexed by the terminal identifier, encapsulates the information of the satellite identifier and terminal identifier of the landing gateway station, looks up the inter - satellite forwarding table, and forwards it to the terrestrial routing equipment of the landing gateway station.

[0026] After receiving the RIP message, the terrestrial routing equipment generates a user identifier mapping table. The terrestrial routing equipment runs the OSPF routing protocol and spreads the satellite user network routing information to the wide - area controller. The wide - area controller runs the OSPF routing protocol and spreads the satellite user network routing information to all CPE equipment.

[0027] Among them, the ground routing device and the wide - area controller are set to the same network segment. The OSPF protocol packets sent by the ground routing device are intercepted by the POP site, encapsulated and sent to the wide - area controller through the bearer network IP tunnel.

[0028] After the CPE device starts, it automatically connects to the affiliated POP site. The CPE device runs the OSPF routing protocol, obtains the information of the reachable network segments of the ground users, and spreads the ground user network routing information to the wide - area controller. The wide - area controller selects the landing gateway station and sends the ground user network routing information to the ground routing device of the landing gateway station through the OSPF protocol packets.

[0029] Among them, the wide - area controller encapsulates the OSPF packets and sends them to the POP site through the bearer network IP tunnel. After the POP site restores the OSPF packets, it sends them to the ground routing device.

[0030] After the ground routing device receives the ground user network routing information, it generates a RIP packet including the reachable network segments of the ground users and the virtual terminal identifier, and sends it to the satellite node. After the satellite routing device receives the RIP packet, it broadcasts it to other satellite nodes and broadcasts it to all user terminals under this satellite. The user routing device receives the RIP packet and generates a user identifier mapping table.

[0031] When an IGSO satellite user accesses a ground network user, the addressing process of the data packet is as follows: The user routing device receives the IP data packet, looks up the user identifier mapping table according to the destination IP address, and obtains the virtual terminal identifier information of the landing gateway station. The user routing device encapsulates the virtual terminal identifier in the IP data packet and sends it to the satellite node. The satellite routing device looks up the layer - 2 mapping table according to the virtual terminal identifier in the IP data packet to obtain the terminal identifier and satellite identifier information of the landing gateway station. The satellite routing device encapsulates the satellite identifier and terminal identifier in the IP data packet, looks up the inter - satellite forwarding table, and forwards it hop - by - hop to the landing gateway station. The ground routing device judges the terminal identifier in the IP data packet. If it is the same as this station, it restores the original IP data packet and forwards it to the POP site. The POP site encapsulates the IP data packet in the bearer network IP tunnel and sends it to the CPE device. The CPE device restores the original IP data packet and forwards it to the service terminal.

[0032] When a terrestrial network user accesses an IGSO satellite user, the addressing process of the data packet is as follows: The CPE device receives the IP data packet and encapsulates it into an IP tunnel of the bearer network and sends it to the home POP site. The home POP site determines whether the current gateway station is a landing gateway station. If so, it forwards the packet to the terrestrial routing device. Otherwise, it encapsulates the IP tunnel of the bearer network and sends it to the POP site of the landing gateway station. After receiving the IP data packet, the terrestrial routing device looks up the user identification mapping table to obtain the satellite identification and terminal identification information of the user terminal. The terrestrial routing device encapsulates the satellite identification and terminal identification in the IP data packet and sends it to the satellite node. The satellite routing device looks up the inter-satellite forwarding table according to the satellite identification of the IP data packet and forwards it hop by hop to the user terminal. After receiving the IP data packet, the user terminal determines the terminal identification in the IP data packet. If it is the same as the user terminal itself, it forwards the IP data packet to the service terminal. Otherwise, it discards the IP data packet.

[0033] Through designs such as on-board layer-2 switching, wide-area networking between stations, routing controlled diffusion, and double-layer routing addressing, the present invention realizes the routing interconnection and service intercommunication between the IGSO satellite communication network and the terrestrial network.

[0034] In summary, the present invention uniquely creates a cross-domain routing system suitable for the periodic landing handover of the IGSO constellation, which can be applied to the scenario where IGSO satellite users land through the gateway station and communicate with terrestrial network users. It can improve the stability of the system routing, reduce the routing interaction overhead, and at the same time achieve the purpose of seamless handover of IGSO satellite users to the landing gateway station.

[0035] Finally, it should be noted that the above are only the preferred examples of the present invention. Although the present invention has been described in detail with reference to the above embodiments, for those skilled in the art, they can still modify the technical solutions of the foregoing embodiments, or perform equivalent replacements on other technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cross-domain routing system suitable for periodic landing handover of an IGSO constellation, characterized in that It includes satellite routing equipment, terrestrial routing equipment, user routing equipment, POP sites, CPE equipment, and a wide-area controller. Among them, the satellite routing equipment is deployed at the IGSO satellite node, the terrestrial routing equipment and POP sites are deployed at the gateway station, the user routing equipment is deployed at the user terminal, the CPE equipment is deployed at the edge of the bearer network user, and the wide-area controller is co-located with any POP site; the routing information between IGSO satellite users and terrestrial network users is diffusely controlled through the wide-area controller, and the service information is forwarded on demand through the POP site; The satellite routing equipment runs the OSPF routing protocol, sets the satellite identifier as the IP address of the LoopBack interface, and after routing convergence, generates an inter-satellite forwarding table indexed by the satellite identifier; The terrestrial routing equipment calculates the availability of the feeder link of the current gateway station according to the IGSO ephemeris information. If it is available, it periodically sends the satellite identifier mapping information of the landing gateway station to the satellite routing equipment. Otherwise, it stops sending the satellite identifier mapping information; after receiving the satellite identifier mapping information of the landing gateway station, the satellite routing equipment generates a layer-2 mapping table indexed by the terminal identifier; The user routing equipment runs the RIP routing protocol, obtains the reachable network segment information of satellite users, generates a RIP packet including the reachable network segment of satellite users, satellite identifier, and terminal identifier, and sends it to the satellite node; after receiving the RIP packet, the satellite routing equipment generates a layer-2 forwarding table indexed by the terminal identifier, encapsulates the information of the satellite identifier and terminal identifier of the landing gateway station, looks up the inter-satellite forwarding table, and forwards it to the terrestrial routing equipment of the landing gateway station; After receiving the RIP packet, the terrestrial routing equipment generates a user identifier mapping table; the terrestrial routing equipment runs the OSPF routing protocol to diffuse the satellite user network routing information to the wide-area controller; the wide-area controller runs the OSPF routing protocol to diffuse the satellite user network routing information to all CPE equipment; After the CPE equipment is started, it automatically connects to the affiliated POP site; the CPE equipment runs the OSPF routing protocol to obtain the reachable network segment information of terrestrial users, and diffuses the terrestrial user network routing information to the wide-area controller; the wide-area controller selects the landing gateway station and sends the terrestrial user network routing information to the terrestrial routing equipment of the landing gateway station through the OSPF protocol packet; After receiving the terrestrial user network routing information, the terrestrial routing equipment generates a RIP packet including the reachable network segment of terrestrial users and virtual terminal identifier, and sends it to the satellite node; after receiving the RIP packet, the satellite routing equipment broadcasts it to other satellite nodes and broadcasts it to all user terminals under this satellite; after receiving the RIP packet, the user routing equipment generates a user identifier mapping table.

2. The cross-domain routing system suitable for periodic landing handover of an IGSO constellation according to claim 1, wherein, When an IGSO satellite user accesses a terrestrial network user, the user routing equipment receives an IP data packet, looks up the user identifier mapping table according to the destination IP address, and obtains the virtual terminal identifier information of the landing gateway station; The user routing equipment encapsulates the IP data packet with the virtual terminal identifier and sends it to the satellite node; The satellite routing device looks up the Layer 2 mapping table based on the virtual terminal identifier in the IP data packet to obtain the terminal identifier and satellite identifier information of the landing gateway station; the satellite routing device encapsulates the satellite identifier and terminal identifier in the IP data packet, looks up the inter-satellite forwarding table, and forwards it hop by hop to the landing gateway station. The terrestrial routing device determines the terminal identifier in the IP data packet. If it is the same as this station, it restores the original IP data packet and forwards it to the POP site; the POP site encapsulates the IP data packet in a carrier network IP tunnel and sends it to the CPE device; the CPE device restores the original IP data packet and forwards it to the service terminal.

3. The cross-domain routing system suitable for periodic landing handover of an IGSO constellation according to claim 1, wherein, When a terrestrial network user accesses an IGSO satellite user, the CPE device receives the IP data packet, encapsulates it in a carrier network IP tunnel and sends it to the POP site to which it belongs; the POP site to which it belongs determines whether the current gateway station is a landing gateway station. If so, it forwards it to the terrestrial routing device. Otherwise, it encapsulates the carrier network IP tunnel and sends it to the POP site of the landing gateway station; after receiving the IP data packet, the terrestrial routing device looks up the user identifier mapping table to obtain the satellite identifier and terminal identifier information of the user terminal. The terrestrial routing device encapsulates the satellite identifier and terminal identifier in the IP data packet and sends it to the satellite node. The satellite routing device looks up the inter-satellite forwarding table based on the satellite identifier of the IP data packet and forwards it hop by hop to the user terminal; after receiving the IP data packet, the user terminal determines the terminal identifier in the IP data packet. If it is the same as this user terminal, it forwards the IP data packet to the service terminal. Otherwise, it discards the IP data packet.

4. A cross-domain routing system suitable for periodic ground handover of an IGSO constellation according to claim 1, characterized in that, The Layer 2 mapping table includes the information of the terminal identifier and satellite identifier of the landing gateway station.

5. The cross-domain routing system suitable for periodic landing handover of an IGSO constellation according to claim 1, wherein The terrestrial routing device and the wide area controller are set to the same network segment. The OSPF protocol packets sent by the terrestrial routing device are intercepted by the POP site, encapsulated in a carrier network IP tunnel and sent to the wide area network controller.

6. The cross-domain routing system suitable for periodic landing handover of an IGSO constellation according to claim 1, wherein, The wide area controller selects the landing gateway station and sends the terrestrial user network routing information to the terrestrial routing device of the landing gateway station through the OSPF protocol packet. The specific method is: the wide area controller encapsulates the OSPF packet in a carrier network IP tunnel and sends it to the POP site. The POP site restores the OSPF packet and sends it to the terrestrial routing device.

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