A satellite network simulation platform

Abstract

The application discloses a satellite network simulation platform, a satellite node simulator for simulating satellites in a satellite network, a ground node simulator for simulating ground stations, a constellation simulation system for simulating spatial positions of the satellites in the satellite network, thereby obtaining a topology of the constellation network, an SDN controller for updating routing tables between the satellite node simulators and between the satellite node simulator and the ground node simulator according to the topology of the constellation network, a link on-off system for controlling links between the satellite node simulators and between the satellite node simulator and the ground node simulator according to the topology of the constellation network, and a test traffic generator for providing test traffic for the satellite node simulators. The satellite node simulator is further configured to transmit the test traffic between the satellite node simulators and / or between the satellite node simulator and the ground node simulator according to the routing tables.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite network, and particularly relates to a satellite network simulation platform. BACKGROUND

[0002] As an effective supplement and backup of ground communication network, the low-orbit satellite network has a wide coverage, is not sensitive to geographical terrain and distance factors, and has strong invulnerability compared with the traditional ground network, and can be applied to aviation communication, maritime communication, emergency support, military communication and other fields, and has important social value and military value.

[0003] At present, the low-orbit satellite network is mainly researched by using simulation means, and a high-credibility satellite network model is established through reasonable abstraction and simplification. The current simulation means of the satellite network is pure software simulation or pure physical networking simulation. The pure software simulation has the advantages of flexible deployment and rapid expansion through the general simulation tool for the inherent characteristics of the low-orbit satellite network topology rapid change, but all nodes of the pure software simulation are virtual nodes, so that the real scene cannot be restored (for example, the loss of physical hardware cannot be simulated). The cost of the pure physical networking simulation is high, and the deployment is complex, and a large-scale network environment cannot be provided.

[0004] Therefore, at present, a satellite network simulation platform combining pure physical networking simulation and pure software simulation is urgently needed, which is used for researching the low-orbit satellite network, especially the networking protocol and inter-satellite routing protocol, so as to verify the service performance and stability of the satellite network. SUMMARY

[0005] The present application provides a satellite network simulation platform combining pure physical networking simulation and pure software simulation, which is used for researching the low-orbit satellite network, especially the networking protocol and inter-satellite routing protocol, so as to verify the service performance and stability of the satellite network.

[0006] The application provides a satellite network simulation platform, comprising: a satellite node simulator, a ground node simulator, a constellation simulation system, an SDN controller, a link on-off system, and a test traffic generator; the satellite node simulator is used for simulating satellites in a satellite network, and comprises virtual satellite simulation nodes and physical satellite simulation nodes; the ground node simulator is used for simulating ground stations; the constellation simulation system is used for simulating spatial positions of the satellites in the satellite network, so as to obtain a topology of a constellation network; the SDN controller is used for updating routing tables between the satellite node simulators and between the satellite node simulators and the ground node simulator according to the topology of the constellation network; the link on-off system is used for controlling links between the satellite node simulators and between the satellite node simulators and the ground node simulator according to the topology of the constellation network; and the test traffic generator is used for providing test traffic for the satellite node simulators; and the satellite node simulator is further used for transmitting the test traffic between the satellite node simulators and / or between the satellite node simulators and the ground node simulator according to the routing tables.

[0007] In one or more embodiments, the virtual satellite simulation nodes are implemented by containers in virtual machines, and the physical satellite simulation nodes are implemented by all-programmable switches.

[0008] In one or more embodiments, there is no common virtual satellite simulation node in different virtual machines, and the total number of connection links between a virtual satellite simulation node in a virtual machine and virtual satellite simulation nodes in other virtual machines is not greater than the maximum port number of the virtual machine.

[0009] In one or more embodiments, resources consumed by the virtual machines and resources consumed by the switches satisfy a simulation performance parameter; the resources consumed by the virtual machines are CPU core / thread numbers and memory sizes, and the resources consumed by the switches refer to the number of the switches.

[0010] In one or more embodiments, the link on-off system comprises a link on-off controller and a link on-off management device; the link on-off controller is used for determining link on-off instructions according to the updated topology of the constellation network; and the link on-off management device is used for controlling links between the satellite node simulators and between the satellite node simulators and the ground node simulator according to the link on-off instructions.

[0011] In one or more embodiments, the link on-off management device is implemented by cascading multiple switches.

[0012] In one or more embodiments, the satellite network simulation platform further comprises a constellation visualization device, which is used for displaying spatial positions of the satellites in the satellite network and the topology of the constellation network.

[0013] In one or more embodiments, the test traffic generator is implemented by a programmable network tester.

[0014] In one or more embodiments, in each time slice, the ground node simulator establishes a connection with a plurality of satellite node simulators through the link on-off management device, the corresponding satellites of the plurality of satellite node simulators being best located with the ground station.

[0015] In one or more embodiments, the link on-off management device comprises a data channel switching network and a control plane switching network, the data channel switching network being used for data transmission with the satellite node simulator and the ground node simulator; the control plane switching network being used for sending control instructions to the satellite node simulator and the ground node simulator. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 A structural schematic diagram of a satellite network simulation platform provided by an embodiment of the present application is shown in the figure.

[0018] Figure 2 A schematic diagram of a semi-physical networking provided by an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] In the embodiments of the present application, multiple means two or more. The words "first", "second", etc. are only used for the purpose of distinguishing description, and cannot be understood as indicating or implying relative importance, nor can it be understood as indicating or implying order.

[0021] At present, both general software simulation tools and physical networking methods can simulate the orbit and satellite operation, satellite antenna, space link performance, network traffic and protocol. Physical networking can provide the best simulation performance, and general software simulation tools have the advantages of flexible deployment and rapid expansion due to the inherent characteristics of low-orbit satellite network topology rapid change. However, each of the two methods has the following defects:

[0022] Pure physical networking simulation: (1) The cost of pure physical networking is high, and the deployment is complex, which cannot provide a large-scale network environment; (2) The physical device has limited support for the protocol and is slow to update.

[0023] Pure software simulation: (1) All nodes are virtual simulation nodes, so it is impossible to provide a high degree of restoration of the real scene (such as simulating the wear and tear of physical hardware); (2) The simulation tool platform basically does not design a separate network control plane, which cannot support new SDN networks; (3) The simulation tool platform does not implement programmable capabilities at the switch node, which cannot meet the needs of special users; (4) It does not support multi-node deployment, and the performance is affected by the performance of the host.

[0024] Based on the above background, the application provides a satellite network simulation platform combining physical networking simulation and pure software simulation, which is used for researching low-orbit satellite networks, especially networking protocols and inter-satellite routing protocols, to verify the business performance and stability of the satellite network.

[0025] Through the satellite network simulation platform provided by the application, the feasibility of the satellite network design scheme can be evaluated and demonstrated in the planning and construction stage; in the system configuration stage, a variety of possible parameter configuration situations are simulated and compared to optimize the configuration of system parameters; before important facilities are deployed, simulation testing is performed to discover possible risks and hidden dangers in advance; in the technical research and development stage, new technologies and new protocols are tested and evaluated for performance.

[0026] Figure 1 A structure diagram of a satellite network simulation platform provided by an embodiment of the application is shown in Figure 1 The satellite network simulation platform includes a satellite node simulator 110, a ground node simulator 120, a constellation simulation system 130, an SDN controller 140, a link on-off system 150, and a test traffic generator 160.

[0027] The satellite node simulator 110 is used to simulate satellites in a satellite network and includes a virtual satellite simulation node 111 and a physical satellite simulation node 112. The virtual satellite simulation node 111 can be implemented by a container in a virtual machine, and the physical satellite simulation node 112 can be implemented by a fully programmable switch.

[0028] If a larger satellite constellation is to be simulated, the number of virtual satellite simulation nodes or physical satellite simulation nodes can be increased. If a satellite constellation of other configuration is to be simulated, the connection relationship between the satellite simulation nodes can be changed.

[0029] The ground node simulator 120 is configured to simulate a ground station. In each time slice, the ground node simulator 120 establishes a connection with a plurality of satellite node simulators through the link on-off management device 152, wherein the plurality of satellite node simulators correspond to satellites that are best positioned with the ground station. Typically, the ground station establishes a connection with three satellites that are best positioned with the ground station.

[0030] The connection relationship between the satellite nodes and between the ground node and the satellite nodes is described below by way of example. It is assumed that the low-orbit satellite network simulated by the satellite network simulation platform is an m*n satellite array, i.e., the satellite network has m orbital planes, and each orbital plane has n satellites. The ground station selects three satellites that are best positioned with the ground station in real time to establish a satellite-ground link, and each satellite forms an inter-satellite network by establishing four links with neighboring satellites in the left, right, north, and south directions. In the actual operation of the satellites, the order between the satellites in the same orbital plane is fixed, so for a single satellite, the topology of the two links in the north-south direction is fixed. However, as the satellites keep moving, the positions of the satellites in the left and right orbital planes of the satellite change rapidly, and thus the two satellites adjacent to the satellite in the left and right directions also change constantly, so the left and right links of the satellite also need to change rapidly to achieve optimal networking.

[0031] The constellation simulation system 130 is configured to simulate the spatial positions of the satellites in the satellite network, thereby obtaining the topology of the constellation network.

[0032] The constellation simulation system 130 simulates the real position distribution of each satellite in space in real time, and sends the position distribution between the satellites to the link on-off system 150.

[0033] The SDN controller 140 is configured to update the routing table between the satellite node simulators and between the satellite node simulator and the ground node simulator according to the topology of the constellation network. Specifically, the SDN controller 140 determines the topology of the constellation network according to the real position distribution of each satellite in space simulated by the constellation simulation system 130, determines the routing table between the satellite node simulators and between the satellite node simulator and the ground node simulator according to the topology of the constellation network, and distributes the updated routing table to the ground node simulator. The ground node simulator sends the received routing table to the satellite node simulators connected thereto, and the satellite node simulators forward the routing table to the entire satellite network by flooding.

[0034] A link on-off system 150 is configured to control the on-off of links between the satellite node emulators and between the satellite node emulators and the ground node emulators according to the topology of the constellation network.

[0035] Further, the link on-off system 150 includes a link on-off controller 151 and a link on-off management device 152. The link on-off controller 151 is configured to determine link on-off instructions according to the topology of the constellation network and send the link on-off instructions to the link on-off management device 152. The link on-off management device 152 is configured to receive the link on-off instructions sent by the link on-off controller 151 and control the on-off of links between the satellite node emulators and between the satellite node emulators and the ground node emulators according to the link on-off instructions.

[0036] The link on-off management device 152 includes a data channel switching network and a control plane switching network. The data channel switching network is configured to perform data transmission with the satellite node emulators and the ground node emulators. The control plane switching network is configured to send control instructions to the satellite node emulators and the ground node emulators to realize out-of-band control. The control plane switching network can be integrated into the satellite-ground data channel switching network to realize in-band control, which is closer to the actual network operation. The link on-off management device can be realized by cascading multiple switches.

[0037] A test traffic generator 160 is configured to provide test traffic for the satellite node emulators 110. The test traffic generator can be realized by a programmable network tester.

[0038] The satellite node emulators 110 are further configured to perform transmission of test traffic between the satellite node emulators and / or between the satellite node emulators and the ground node emulators according to the routing table.

[0039] In one or more embodiments, the satellite network simulation platform further includes a constellation visualization device 170 configured to visualize the spatial positions of the satellites in the satellite network and the topology of the constellation network.

[0040] In the embodiments of the present application, the satellite network simulation platform uses a hybrid networking of real physical simulation nodes and container-based virtual satellite simulation nodes, i.e., part of the topology is implemented using containers in virtual machines and part of the topology is implemented using real objects. On the one hand, a large-scale network environment can be provided, and on the other hand, the network environment is closer to the real environment of satellite operation, and the experimental results are more realistic.

[0041] The implementation of the container-based virtual satellite simulation node is that multiple virtual satellite simulation nodes can be established on a host computer through a container, the virtual satellite simulation node is connected to the host computer through a virtual network interface, and the host computer can manage and configure the virtual satellite simulation node, such as adding and migrating. Each virtual satellite simulation node has an independent namespace, that is, the routing table and the ground station agent in the virtual satellite simulation node work independently and are simultaneously mapped to an independent host computer memory space. The host computer can simulate any constellation topology by configuring the virtual network interface.

[0042] Exemplarily, as shown in Figure 2 FIG. 6, a satellite network composed of six satellites is taken as an example, satellite A and satellite B are implemented by physical satellite simulation nodes, and satellite C, satellite D, satellite E and satellite F are implemented by virtual satellite simulation nodes. The physical network interfaces of satellite A and satellite B are connected to the physical network interfaces of the container host computer, and an equivalent global simulation topology is implemented by configuring a virtual switch in the container host computer. The virtual switch can connect satellite A node to satellite C node and connect satellite B node to satellite D node through a VLAN or the like. The final topology is equivalent to the 6-star topology shown in the upper part.

[0043] The divided topology structure satisfies that there is no common virtual satellite simulation node in different virtual machines, and the total number of connection links between the virtual satellite simulation node in a virtual machine and the virtual satellite simulation nodes in other virtual machines is not greater than the maximum port number of the virtual machine. The resources consumed by the virtual machine and the resources consumed by the switch satisfy the simulation performance parameters. The resources consumed by the virtual machine are CPU core / thread number and memory size, and the resources consumed by the switch are the number of switches.

[0044] Specifically, the network topology segmentation method is as follows:

[0045] The satellite simulation network topology is defined as a graph G(V, E), where V is the node set of the graph G, and E is the edge set of the graph G. The mapping type: V→{vsw, vhost} is used to represent the node type in the topology, that is, the node is mapped to a physical switch or a host computer. The purpose of topology segmentation is to find a complete disjoint partition P of the node set V of the graph G.

[0046] The input of the topology segmentation model is the application topology G(V, E) of the user slice, type: V→{vsw, vhost} and the simulation performance parameter K∈(0, 1].

[0047] The output is the partition P of the node set of the graph G:

[0048] Wherein P satisfies the following conditions:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] wherein, formula 1 defines hardware switch hsw i for the switch in the simulation topology, V j for the sub-topology after being partitioned.

[0055] In formula 2, the current partition P is a complete partition, and there is no overlap between partitions. That is, there is no common node between two sub-topologies; the switch node does not belong to the part of the sub-topology; and the switch and the sub-topology together constitute the node set V.

[0056] using constant hsw limit and vm limit The number of physical switch and virtual machine devices is specified as a constraint for solving the partition P, and the specific constraint is:

[0057]

[0058]

[0059] k≤hsw limit

[0060] q≤vm limit (formula 3)

[0061] wherein, port hsw is the maximum number of ports of the hardware switch, which is a platform-level constant.

[0062] port vm is the maximum number of ports of a single virtual machine, which is a platform-level constant.

[0063] hsw limit is the number of available hardware switches in the platform, which is a single partition-level constant.

[0064] vm limit is the number of available virtual machines in the platform, which is a single partition-level constant.

[0065] That is, formula 3 indicates that the degree of the switch node is less than or equal to the maximum number of ports of the switch; and the total number of edges of the sub-topology and other sub-topologies is less than or equal to the maximum number of ports of the virtual machine.

[0066] In order to improve the whole simulation verification performance after the topology segmentation as much as possible under the condition of the least resource consumption. Define cost(P) as the resource consumption of each segmentation.

[0067] cost(P) = kcost hsw + qcost vm (Formula 4)

[0068] Wherein, cost hsw is the resource consumption cost hsw of a single hardware switch, platform-level constant.

[0069] cost vm is the resource consumption of a single virtual machine, platform-level constant.

[0070] In formula 4, k is the number of physical switches in the segmented topology, and q is the number of virtual machines in the segmented topology. cost hsw and cost vm Two constants are the cost of each hardware switch resource and each virtual machine.

[0071] In order to measure the experimental performance of the divided topology, define its performance measurement index as:

[0072]

[0073] The final objective function is

[0074] f(P) = min cost(P)

[0075] = min kcost hsw + qcost vm

[0076] s.t. Performance(P) ≥ K

[0077] In formula 5, it is a simulation performance parameter. Performance(p) refers to the minimum load of all hardware resources, which can be optimized by the objective function segmentation to make the load of hardware resources as balanced as possible.

[0078] By segmenting the global topology, the most suitable physical and container virtual network segmentation point can be found, so that the connection relationship of the physical and container virtual network is the simplest. Without specifying the physical simulation node, the network management complexity can be greatly reduced. Topology segmentation not only supports automatic execution according to resource conditions, but also can be intervened by user specified key nodes. The authenticity of the simulation platform is guaranteed to the greatest extent, and the cost of manual allocation of resources is reduced.

[0079] A specific hardware implementation of the satellite network simulation platform provided in the embodiments of the present application is introduced below. The physical satellite simulation node is implemented by a fully programmable switch ONetSwitch. The fully programmable switch ONetSwitch is a fully programmable open network innovation platform based on an Xilinx SoC chip. The software and hardware of the fully programmable switch ONetSwitch can be programmed and customized. The fully programmable switch ONetSwitch can simulate an actual constellation and has the ability to be directly deployed on a satellite. The main architecture and parameter requirements of the fully programmable switch ONetSwitch are as follows: the chip includes a processing system with a dual-core ARM Cortex-A9 application processor as the core and programmable logic based on an Xilinx Kintex7 series FPGA. The processor system has 8 channels of DMA (4 channels are dedicated to programmable logic), 1 Gbyte of dynamic random access memory, and has one GE RJ45 gigabit network interface. The FPGA programmable logic has about 5.2M logic gates, a bus throughput of 100Gbps, and has four GE RJ45 gigabit electrical ports and four 10GE SFP+ gigabit optical ports. The test traffic generator is implemented by a programmable network tester InterONet. The programmable network tester InterONet is a full-stack programmable SDN testbed system supporting the SDN standard OpenFlow protocol. The programmable network tester InterONet can realize full-stack programmability of the data plane, the control plane, and the network topology. The ground node simulator is implemented by an X86 server. The link on-off management device is formed by cascading five Cisco Catalyst WSC2960S-48TS-L switches with management functions to form an array, which constitutes a 240-port switching device. The constellation simulation, constellation visualization, on-off controller, and SDN centralized controller four software modules are respectively run in the respective host computers.

[0080] The satellite network platform provided in the present application can more flexibly meet the demand for quickly updating the topology of a low-orbit satellite network and correspondingly changing the route, relative to the existing pure software simulation and pure physical networking simulation. The satellite network platform has the following advantages:

[0081] 1. The satellite network platform provided in the present application uses a fully programmable switch to implement part of the satellite simulation nodes and uses a lightweight container to implement part of the satellite simulation nodes. This hybrid networking method can simulate a large-scale real network and also ensure the performance (such as stable bandwidth and deterministic delay) of key nodes, thereby maximizing the simulation of real scenarios in terms of function and performance.

[0082] 2. Unlike the traditional routing protocol that needs to exchange routing information between each switch, the SDN controller with a global view can directly make routing decisions on the topology, such as the shortest path. Therefore, the routing update time can be greatly reduced, and the route stability can be ensured.

[0083] 3. Using all programmable switch as the carrier of part of satellite simulation nodes, the programmable switch can support the complex and changeable satellite network networking protocol, application protocol stack and other changeable characteristics quickly.

[0084] While the preferred embodiments of the application have been described, additional variations and modifications can be made to the preferred embodiments by those skilled in the art once they learn of the basic inventive concepts. Therefore, the appended claims are intended to encompass within their scope all such variations and modifications as are included within the scope of the application.

[0085] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the application. Accordingly, it is intended that the application embrace all such modifications and changes as fall within the scope of the appended claims and their equivalents.

Claims

1. A satellite network simulation platform, characterized by, The system comprises: a satellite node simulator, a ground node simulator, a constellation simulation system, an SDN controller, a link on-off system, and a test traffic generator; the satellite node simulator is configured to simulate a satellite in a satellite network, and comprises a virtual satellite simulation node and a physical satellite simulation node; the ground node simulator is configured to simulate a ground station; the constellation simulation system is configured to simulate spatial positions of the satellites in the satellite network, thereby obtaining a topology of the constellation network; the SDN controller is configured to update routing tables between the satellite node simulators and between the satellite node simulators and the ground node simulator according to the topology of the constellation network, and to distribute the updated routing tables to the ground node simulator; the ground node simulator is further configured to send the received routing tables to the satellite node simulators connected thereto; the satellite node simulator is configured to forward the routing tables to the entire satellite network in a flooding manner; the link on-off system is configured to control links between the satellite node simulators and between the satellite node simulators and the ground node simulator according to the topology of the constellation network; the link on-off system comprises a link on-off controller and a link on-off management device; the link on-off controller is configured to determine link on-off instructions according to the updated topology of the constellation network; the link on-off management device is configured to control links between the satellite node simulators and between the satellite node simulators and the ground node simulator according to the link on-off instructions; the test traffic generator is configured to provide test traffic for the satellite node simulators; the satellite node simulator is further configured to transmit the test traffic between the satellite node simulators and / or between the satellite node simulators and the ground node simulator according to the routing tables.

2. The satellite network emulation platform of claim 1, wherein, The virtual satellite simulation node is implemented by a container in a virtual machine, and the physical satellite simulation node is implemented by a fully programmable switch.

3. The satellite network emulation platform of claim 2, wherein, There is no common virtual satellite simulation node in different virtual machines, and the total number of connection links between the virtual satellite simulation node in a virtual machine and virtual satellite simulation nodes in other virtual machines is not greater than the maximum port number of the virtual machine.

4. The satellite network emulation platform of claim 3, wherein, The resources consumed by the virtual machine and the resources consumed by the switch satisfy simulation performance parameters. The resources consumed by the virtual machine are CPU core / thread occupation and memory size, and the resources consumed by the switch are the number of switches.

5. The satellite network emulation platform of claim 1, wherein, The link on-off management device is implemented by cascading multiple switches.

6. The satellite network emulation platform of claim 1, wherein, The system further comprises a constellation visualization device configured to display spatial positions of the satellites in the satellite network and the topology of the constellation network.

7. The satellite network emulation platform of claim 1, wherein, The test traffic generator is implemented by a programmable network tester.

8. The satellite network emulation platform of claim 1, wherein, In each time slice, the ground node simulator establishes a connection with multiple satellite node simulators through the link on-off management device, and the corresponding satellites of the multiple satellite node simulators have the best positions relative to the ground station.

9. The satellite network emulation platform of claim 1, wherein, The link on-off management device comprises a data channel switching network and a control plane switching network, and the data channel switching network is configured to perform data transmission with the satellite node simulators and the ground node simulator. The control plane switching network is configured to send control instructions to the satellite node emulator and the ground node emulator.

Images