Dynamic link regulation and control method for large-scale satellite network simulation platform

Abstract

The invention belongs to the field of satellite network simulation, and particularly relates to a link dynamic regulation and control method for a large-scale satellite network simulation platform. The method is characterized by comprising the following steps: an eBPF program searches simulation starting time of current equipment from an eBPF Map by taking an equipment index as a key; judging whether simulation is started or not, and if not, searching the simulation starting time of the current equipment again; if the simulation is started, calculating a timestamp according to the system time and the simulation starting time, and searching link state information of the current equipment at the current moment from the eBPF Map by taking the timestamp and the equipment index as keys; and the eBPF program executes link regulation and control logic based on the eBPF according to the link state information. According to the method, the system resource overhead during formal simulation is reduced, large-scale dynamic link state regulation and control with finer time granularity can be supported, and the simulation logic of the satellite node during formal simulation cannot be influenced.

Description

Technical Field

[0001] The invention belongs to the field of satellite network simulation, and in particular relates to a link dynamic control method for a large-scale satellite network simulation platform. Background Art

[0002] As a new type of network system, satellite network has broad application prospects in both military and civilian scenarios due to its ability to provide high coverage and low latency services. In order to develop satellite network related technologies, such as inter-satellite routing technology, satellite-to-ground routing technology and satellite network protocols, a verification platform is needed to verify the feasibility of new satellite network related technologies.

[0003] At present, there are two ways to implement the verification platform: the real hardware verification platform and the simulation software verification platform. Since satellite network equipment is expensive and its working logic is difficult to modify after the hardware is solidified, building a real hardware satellite network technology verification platform based on real satellite network equipment has the disadvantages of being uneconomical and inflexible. Therefore, the more economical and flexible software-based network simulation verification platform is more favored by researchers. Considering the large-scale and highly dynamic characteristics of low-orbit satellite networks, that is, the number of links between satellite nodes in the satellite network will be very large (thousands or even tens of thousands), and the link status of these links (link disconnection, link delay, link bandwidth) will frequently change with time, the simulation verification platform should have the ability to simulate large-scale and highly dynamic networks.

[0004] At present, there are three technical routes for software-based satellite network simulation and verification platforms, namely, pure physical model simulation, physical model computing events combined with discrete event software simulation, and physical model computing events combined with network function virtualization technology simulation. Since the hardware of satellite routing equipment needs to operate stably in the complex environment of space, before the hardware of satellite routing equipment enters space, it is necessary to test the functions and physical characteristics of the hardware of satellite routing equipment during operation, that is, to connect the hardware of satellite routing equipment to the satellite network simulation and verification platform to complete semi-physical simulation verification. In order to complete the semi-physical simulation verification, the satellite network simulation and verification platform needs to have the function of exchanging data with the physical equipment. In the current satellite network simulation platform implementation, only the technical route of simulation based on physical model computing events combined with network function virtualization technology can meet this requirement, so this route has gradually become the mainstream satellite network simulation and verification platform implementation method.

[0005] The existing work on the technical route of simulation verification platform based on physical model computing events combined with network function virtualization technology reduces the simulation overhead of satellite nodes by using lightweight virtualization technology, which alleviates the resource overhead caused by the large-scale characteristics of satellite networks to a certain extent. However, in dealing with the problem of high dynamics of links in satellite networks, the dynamic link control scheme given by the above existing work has three limitations. The first limitation is that the dynamic link control logic runs in the formal simulation stage, which means that when the satellite network simulation verification platform is in formal simulation, in addition to the resource overhead caused by the virtual satellite network simulation logic, the system also needs to bear the resource overhead caused by the dynamic link control logic. And this overhead will consume more system resources as the time granularity is finer and the link status events are more. The second limitation is that the dynamic link control logic is real-time, which means that within a time granularity, the link status of all links needs to be updated, otherwise it will affect the simulation of the next time granularity. The Linux used in the existing work The tc tool needs to create a new process every time it regulates a link. Executing a large number of link regulation operations in a short period of time means creating a large number of new processes in a short period of time, which is undoubtedly very time-consuming. Therefore, it is impossible to handle large-scale link regulation when the time granularity is small. The third limitation is introduced by the use of lightweight virtualization technology, that is, the global lock brought by the shared operating system kernel makes it difficult to parallelize some logic. In particular, in the network simulation environment, the kernel processes link regulation requests and processes routing requests. Share the same processing logic, therefore, a large number of link regulation requests in a short period of time are not only difficult to parallelize, but also squeeze out the routing processing in normal simulation. Based on the above three limitations, the existing work cannot meet the large-scale and highly dynamic link simulation needs of satellite networks. A more efficient link regulation method is urgently needed to meet the simulation needs of large-scale and highly dynamic satellite networks. Summary of the invention

[0006] In view of the shortcomings of the above-mentioned prior art, the problem to be solved by the present disclosure is to provide a method for regulating the dynamic changes of link states for a large-scale, highly dynamic satellite network simulation and verification platform based on eBPF, which can solve the problems existing in the dynamic control scheme of link states given in existing work and meet the large-scale, highly dynamic simulation needs of satellite networks.

[0007] In a first aspect, a link dynamic control method for a large-scale satellite network simulation platform is provided, wherein the satellite network simulation platform runs virtual satellite nodes using lightweight virtualization technology, and the virtual satellite nodes are connected through virtual network links provided by Veth devices, including:

[0008] Load the eBPF program to the veth egress mount point of each virtual satellite node;

[0009] The simulation platform converts the discrete event sequence of link status of all links calculated according to the physical model at a certain event granularity into mapping information with timestamp combined with virtual network device index as key and link status information as value, and pre-stores the mapping information and simulation start time in the eBPF Map;

[0010] Based on the timestamp of the link state when the data packet is sent, the link state information of the current device at the current moment is searched in the eBPF Map, and link regulation is performed based on the link state information.

[0011] The timestamp is calculated based on the system time and the simulation start time. The difference between the system time and the simulation start time is calculated, and the integer part of the difference divided by the simulation time granularity is the timestamp of the current simulation moment of the current link.

[0012] The simulation start time of the device is stored in the eBPF Map of each virtual satellite node.

[0013] Among them, when the link status information of the current device at the current moment is link disconnection information, the eBPF program will directly return the value TC_ACT_SHOT, and this return value will cause the data packet to be discarded.

[0014] Among them, when the link status information of the current device at the current moment is the link delay information, the eBPF program adds the link delay to tstamp, and the data packet is sent according to the value of tstamp.

[0015] Among them, when the link status information of the current device at the current moment is the link packet loss rate information, the eBPF program generates a pseudo-random number. When this pseudo-random number falls into the interval that meets the link packet loss rate, the eBPF program returns the value TC_ACT_SHOT, and this return value causes the data packet to be discarded;

[0016] When the link status information of the current device at the current moment is link bandwidth information, the timestamp of the last packet transmission is obtained from the eBPF Map using the device index as the key;

[0017] If the timestamp of the last packet does not exist, the system timestamp of this packet is stored in eBPFMap using the device index as the key;

[0018] If the timestamp of the last packet transmission exists, obtain the timestamp of the last packet transmission, and calculate the timestamp of the next packet transmission based on the timestamp, link bandwidth, and data packet length;

[0019] Get the system timestamp. When the system timestamp is less than the timestamp of this packet, add the waiting time to the tstamp of the data packet structure, and store the system timestamp of this packet in the eBPF Map with the device index as the key.

[0020] When the system time is greater than or equal to the timestamp of this packet, the system timestamp of this packet is stored in the eBPF Map with the device index as the key.

[0021] In a second aspect, a computer-readable storage medium is provided, on which a computer program / instruction is stored, and the computer program / instruction implements the steps of the above method when executed by a processor.

[0022] According to a third aspect, a computing terminal is provided, including a memory and a processor, wherein the memory stores executable code, and the above method is implemented when the processor executes the executable code.

[0023] Compared with the prior art, the present invention can achieve the following technical effects:

[0024] 1. Since all dynamic link control work has been completed before the formal simulation, the system resource overhead during the formal simulation is reduced.

[0025] 2. Since the eBPF program will calculate the timestamp according to the simulation time granularity during the formal simulation, as long as the link state information associated with the corresponding timestamp is stored in the eBPF Map, the link state changes of the corresponding links can be expressed as discrete link state events divided according to the corresponding time granularity, which can support large-scale dynamic link state control with finer time granularity.

[0026] 3. Since the execution of the eBPF program is embedded in the kernel execution flow, it will not affect the satellite node's call to other kernel codes, and therefore will not affect the simulation logic of the satellite node during the formal simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The workflow of the satellite network simulation verification platform implemented for existing technologies;

[0028] Figure 2 The workflow of the satellite network simulation verification platform using the link dynamic control method for large-scale satellite network simulation platform;

[0029] Figure 3 It is an architecture that combines the link dynamic control method for large-scale satellite network simulation platform with the satellite network simulation verification platform;

[0030] Figure 4The overall operation process of the link dynamic control method for large-scale satellite network simulation platform;

[0031] Figure 5 Execute the process for eBPF programs;

[0032] Figure 6 Execute the link disconnection control logic flow for the eBPF program;

[0033] Figure 7 Execute link latency control and control logic flow for eBPF programs;

[0034] Figure 8 Execute link packet loss rate control and regulation logic flow for eBPF program;

[0035] Fig. 9 Execute link bandwidth control and regulation logic flow for eBPF program; DETAILED DESCRIPTION

[0036] The best mode of implementation of the present invention is described below by way of example. It should be understood that the specific embodiments herein are used to explain the present invention in detail and should not be construed as limiting the present invention. It should be noted that various changes and modifications may be made under the premise of following the principles and core scope of the present invention, and these changes should all be deemed to be within the scope of protection of the present invention. In conjunction with the accompanying drawings, the specific implementation steps of the present invention are described in detail.

[0037] Since the hardware of satellite routing equipment needs to operate stably in the complex environment of space, it is necessary to test the functions and physical characteristics of the satellite routing equipment hardware during operation before the hardware enters space, that is, to connect the satellite routing equipment hardware to the satellite network simulation verification platform to complete the semi-physical simulation verification. In order to complete the semi-physical simulation verification, the satellite network simulation verification platform must have the function of exchanging data with the physical equipment. In the current satellite network simulation platform implementation, only the technical route of simulation based on physical model calculation events combined with network function virtualization technology can meet this requirement. Therefore, this route has gradually become the mainstream satellite network simulation verification platform implementation method.

[0038] In the existing satellite network simulation verification platform, the workflow is generally as follows: Figure 1 As shown:

[0039] The satellite network simulation platform calculates the discrete event sequence of the link status of all links in the satellite network changing over time at a certain time granularity based on the physical model;

[0040] Building virtual satellite nodes based on lightweight isolation mechanisms (such as containers or namespaces);

[0041] Satellite nodes communicate with each other using virtual network links built using the Linux kernel's virtual network device (veth);

[0042] Start all virtual satellite nodes implemented by software;

[0043] When the simulation starts, the simulation platform follows the dynamic link control logic to control the link and follows the virtual satellite simulation logic to perform simulation.

[0044] In the dynamic link control given in existing work, the dynamic link control logic runs in the formal simulation stage, which consumes system resources and cannot handle large-scale link control when the time granularity is small. A large number of link control requests in a short period of time are not only difficult to parallelize, but also occupy the processing of routing in normal simulation, which cannot meet the large-scale and highly dynamic link simulation needs of satellite networks.

[0045] To solve the above problems, the present invention provides a link dynamic control method for a large-scale satellite network simulation platform for a satellite network simulation verification platform that is used for simulating physical model computing events combined with network function virtualization technology.

[0046] The eBPF (Extended Berkeley Packet Filter) program is a precompiled and sandboxed program that can be safely run in the kernel of the Linux system. It is event-triggered, and the execution of the eBPF program is triggered every time a data packet is sent. In particular, the eBPF map is a special data structure used to store and share data between the eBPF program and the user space.

[0047] like Figure 4 and Figure 5 As shown, the link dynamic control method for a large-scale satellite network simulation platform provided by the present invention is specifically as follows:

[0048] Step S1: Load the eBPF program to the veth egress mount point of each virtual satellite node;

[0049] Step S2: The simulation platform converts the link status discrete event sequence of all links calculated according to the physical model at a certain event granularity into mapping information with the timestamp combined with the virtual network device index as the key and the link status information as the value, and pre-stores the mapping information and the device simulation start time in the eBPF Map;

[0050] The specific implementation of step S2 is as follows:

[0051] The simulation platform reads the link-like discrete event sequence and converts it into link status information with timestamp and device index;

[0052] The link status information mainly includes: link connection information, link delay information, link packet loss rate information, and link bandwidth information.

[0053] Load link state information with timestamp and device index into eBPF Map;

[0054] Load the simulation start time into the eBPF Map so that the eBPF program can calculate the timestamp of the current simulation moment of the link;

[0055] Step S3: Based on the timestamp of the link state when the data packet is sent, the link state information of the current device at the current moment is searched in the eBPF Map, and link regulation is performed based on the link state information.

[0056] Specifically, before the simulation starts, the eBPF program will discard all data packets. When the simulation platform stores the simulation start time in the eBPF Map, the eBPF program will start working.

[0057] The specific program execution logic is shown in the figure:

[0058] Use the device index as the key to find the simulation start time of the current device from the eBPF Map;

[0059] Determine whether the simulation has started. If not, continue to use the device index as the key to find the simulation start time of the current device from the eBPF Map;

[0060] If yes, calculate the timestamp based on the system time and the simulation start time, and use the timestamp and device index as keys to find the link status information of the current device at the current moment from the eBPF Map;

[0061] Execute eBPF-based link control logic based on link status information.

[0062] The eBPF program ends the process.

[0063] Specifically, the difference between the system time and the simulation start time is calculated, and the integer part of the difference divided by the simulation time granularity is the timestamp of the current link at the current simulation moment. Link status information mainly includes: link connection information, link delay information, link packet loss rate information, and link bandwidth information.

[0064] It should be noted that every time the simulation platform sends a data packet to the eBPF program, it triggers the running of the eBPF program.

[0065] The eBPF-based link control logic executed according to the link status information includes:

[0066] If the obtained link status time information is link up / down information, such as Figure 6As shown, the eBPF program executes the following control logic:

[0067] If no link disconnection information is obtained, it means that the link remains connected, and the next link control logic is executed;

[0068] If the link is disconnected, the eBPF program will directly return the value TC_ACT_SHOT, which will cause the data packet to be discarded.

[0069] If the obtained link status time information is link delay information, such as Figure 7 As shown, the eBPF program executes the following control logic:

[0070] The eBPF program will modify the time information tstamp field of the data packet structure sk_buff.

[0071] Among them, the sk_buff (socket buffer) structure is an important data structure in the Linux network code, which manages and controls the information of receiving or sending data packets.

[0072] Specifically, the link delay is added to the time information tstamp. After the modification, the data packet will be sent according to the value of the time information tstamp, thereby achieving the effect of link delay control.

[0073] If the obtained link status time information is link packet loss rate information, such as Figure 8 As shown, the eBPF program executes the following control logic:

[0074] After obtaining the link packet loss rate, a pseudo-random number is generated to determine whether packet loss occurs.

[0075] When this pseudo-random number falls into the range that matches the link packet loss rate, the eBPF program will return the value TC_ACT_SHOT, which will cause the data packet to be discarded.

[0076] If it is not in this range, continue to execute the next link control logic.

[0077] If the obtained link status time information is link bandwidth information, such as Fig. 9 As shown, the eBPF program executes the following control logic:

[0078] When the link state information is link bandwidth control, the timestamp of the last packet sent is obtained from the eBPF Map using the device index as the key.

[0079] If the timestamp of the last packet transmission does not exist, it means that the packet transmission has not started yet. The system timestamp of this packet transmission can be stored in the eBPF Map with the device index as the key to enter the next stage of link control logic.

[0080] If the timestamp of the last packet exists, the timestamp of the last packet is obtained. According to the timestamp, link bandwidth and data packet length, the timestamp of the next packet is calculated. That is, the timestamp of the next packet is equal to the timestamp of the last packet plus the data packet length divided by the link bandwidth.

[0081] After calculating the timestamp of the next packet transmission, obtain the system timestamp and compare the system timestamp with the timestamp of the next packet transmission.

[0082] When the system timestamp is less than the timestamp of this packet, it means that it is not time to send the packet yet. The waiting time can be added to the tstamp of the data packet structure, and then the system timestamp of this packet is stored in the eBPF Map with the device index as the key, entering the next stage of link control logic.

[0083] When the system time is greater than or equal to the timestamp of this packet, it means that the packet can be sent. The system timestamp of this packet is directly stored in the eBPF Map with the device index as the key, and the link control logic of the next stage is entered.

[0084] The present invention can improve the simulation process in the satellite network simulation platform, such as Figure 3 The figure shows the architecture of the present invention combined with a satellite network simulation verification platform.

[0085] The satellite network simulation platform calculates the link status of all links in the satellite network according to the physical model, and calculates the discrete event sequence that changes over time at a certain time granularity, and pre-stores it in the eBPF Map. Virtual satellite nodes are connected and communicated through virtual links provided by veth devices. Each virtual satellite node is equipped with an eBPF program, which can query the link status information in the eBPF Map.

[0086] Figure 2 The simulation process of the improved satellite network simulation platform according to the present invention is shown in the figure as one embodiment, and the process includes:

[0087] S1: The satellite network simulation platform calculates the discrete event sequence of the link status of all links in the satellite network changing over time at a certain time granularity based on the physical model;

[0088] S2: Building virtual satellite nodes based on lightweight isolation mechanism;

[0089] In a specific embodiment, the lightweight isolation mechanism may be a container technology Docker or a namespace mechanism.

[0090] Container technology is an isolation technology based on operating system capabilities and is an important solution for resource sharing and isolation in large-scale clusters. The essence of a container is a group of processes that are resource-constrained and isolated from each other, and one or more applications can run in the process.

[0091] Namespace is a mechanism in the Linux kernel that allows multiple independent processes to run on the same system, and each process has its own independent resources and namespace, which can isolate and protect different processes.

[0092] In the satellite network simulation platform, the lightweight isolation mechanism has the advantages of more efficient use of system resources, support for continuous payment and deployment, and easy maintenance.

[0093] S3: Satellite nodes communicate with each other using virtual network links built using the Linux kernel's virtual network device (veth);

[0094] Veth is a kind of Linux virtual network device, which exists in pairs. Each pair of veth devices consists of two endpoints. Data sent from one endpoint can be received by another endpoint, realizing communication between two virtual satellite nodes.

[0095] S4: Run dynamic link control logic.

[0096] In a specific embodiment, Figure 4 As shown, running the dynamic link control logic includes:

[0097] S41. Load the eBPF program to the veth egress mount point of each virtual satellite node.

[0098] The mount point is the entry directory of the disk file system in the Linux system. Through the mount point, users can easily access and manage data on the storage device, such as reading, writing and deleting files.

[0099] In this embodiment, the link status information may be queried through the mount point of the virtual satellite node.

[0100] S42. The reading simulation platform calculates the link status discrete event sequence of all links according to the physical model at a certain event granularity, and converts it into mapping information with timestamp and device index as keys and link status information as values.

[0101] The link status information mainly includes: link connection information, link delay information, link packet loss rate information, and link bandwidth information.

[0102] S43. Store the above mapping information in the eBPF Map.

[0103] S44. The simulation start time is stored in the eBPF Map, the eBPF program starts working, and calculates the timestamp.

[0104] Before the simulation starts, the eBPF program will discard all data packets. After the simulation platform stores the simulation start time in the eBPF Map, the eBPF program will start working and perform dynamic link control according to the ebpf program execution logic of the present invention.

[0105] The timestamp is calculated by calculating the difference between the system time and the simulation start time. The difference divided by the integer part of the simulation time granularity is the timestamp of the current simulation moment of the current link.

[0106] S45: Link control ends and simulation begins.

[0107] S5: Start all virtual satellite nodes implemented by software;

[0108] S6: The simulation starts, and the simulation platform performs simulation according to the virtual satellite simulation logic.

[0109] The difference between the satellite network simulation verification platform implemented based on this solution and the satellite network simulation verification platform implemented by existing work is that the dynamic link control logic is put before the formal simulation. The eBPF program controls the link bandwidth and latency according to the EDT traffic shaping mechanism. Each execution needs to read the link latency and bandwidth configuration from a storage area called eBPF Map that can be read and written by the eBPF program. The link loaded with the eBPF program will naturally show the dynamic changes of the link state that conforms to the physical model calculation during the simulation.

[0110] In the process based on the present invention, the satellite network simulation verification platform builds a virtual link with the characteristics of dynamic changes in link status that conform to the physical model, and there is no need to perform real-time link status regulation during formal simulation.

[0111] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A link dynamic control method for a large-scale satellite network simulation platform, wherein the satellite network simulation platform runs virtual satellite nodes using lightweight virtualization technology, and the virtual satellite nodes are connected through virtual network links provided by Veth devices, characterized in that: include: Load the eBPF program to the veth egress mount point of each virtual satellite node; The simulation platform converts the discrete event sequence of link status of all links calculated according to the physical model at a certain event granularity into mapping information with timestamp combined with virtual network device index as key and link status information as value, and pre-stores the mapping information and simulation start time in the eBPF Map; Based on the timestamp of the link state when the data packet is sent, the link state information of the current virtual satellite device at the current moment is searched in the eBPF Map, and link regulation is performed based on the link state information.

2. The link dynamic control method according to claim 1, characterized in that: Calculate the timestamp based on the system time and the simulation start time: The difference between the system time and the simulation start time is calculated. The integer part of the difference divided by the simulation time granularity is the timestamp of the current simulation moment of the current link.

3. The link dynamic control method according to claim 1, characterized in that: The simulation start time of each virtual satellite device is stored in the eBPFMap of the virtual satellite node.

4. The link dynamic control method according to claim 1, characterized in that: When the link status information of the current virtual satellite device is link disconnection information at the current moment, the eBPF program will directly return the value TC_ACT_SHOT, which will cause the data packet to be discarded.

5. The link dynamic control method according to claim 1, characterized in that: When the link status information of the current virtual satellite device at the current moment is the link delay information, the eBPF program adds the link delay to tstamp, and the data packet is sent according to the value of tstamp.

6. The link dynamic control method according to claim 1, characterized in that: When the link status information of the current virtual satellite device is the link packet loss rate information, the eBPF program generates a pseudo-random number. When the pseudo-random number falls into the interval that meets the link packet loss rate, the eBPF program returns the value TC_ACT_SHOT, which causes the data packet to be discarded.

7. The link dynamic control method according to claim 1, characterized in that: When the link status information of the current virtual satellite device is link bandwidth information, the timestamp of the last packet transmission is obtained from the eBPF Map using the device index as the key; If the timestamp of the last packet does not exist, the system timestamp of this packet is stored in the eBPF Map with the device index as the key; If the timestamp of the last packet transmission exists, obtain the timestamp of the last packet transmission, and calculate the timestamp of the next packet transmission based on the timestamp, link bandwidth, and data packet length; Get the system timestamp. When the system timestamp is less than the timestamp of this packet, add the waiting time to the tstamp of the data packet structure, and store the system timestamp of this packet in the eBPF Map with the device index as the key. When the system time is greater than or equal to the timestamp of this packet, the system timestamp of this packet is stored in the eBPF Map with the device index as the key.

8. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the steps of the method according to claims 1-7 are implemented.

9. A computing terminal, comprising a memory and a processor, wherein the memory stores executable code, and when the processor executes the executable code, the method according to any one of claims 1 to 7 is implemented.

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