A data interaction system for mid-terminal node devices in a satellite-borne real-time network

Abstract

The present invention relates to the field of satellite communication system design and network transmission design, and provides a data interaction system for end node devices in a satellite-borne real-time network. The device end node IP core external interface includes 1 host port, 1 synchronization port and several data ports. According to the needs of actual applications, different functional devices can be matched to quickly realize the construction and data transmission of satellite-borne high-reliability real-time network end nodes. Each layer inside the end node device processes the transmission message based on time scheduling, and also includes a timestamp processing layer, an arrival time scheduling layer and a departure time scheduling layer, a destination query and redundancy elimination layer, and a switching layer. The design of the end node IP core formed by the present invention is convenient for integration into programmable logic devices; the design of the general architecture facilitates the realization of the synchronization function of the satellite-borne real-time network end system and the construction of a redundant network, improves the topological performance of the high-reliability real-time network, and has good engineering effects, convenient debugging, and reduces design costs.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication system design and network transmission design, and in particular to a data interaction system for end node equipment in a satellite-borne real-time network. Background Art

[0002] With the rapid development and advancement of my country's aerospace industry, the demand for satellite services is growing and the scale of data is becoming increasingly large. At the same time, due to the increase in global satellite networking services and the increasingly high requirements of various related industries for on-board information processing, the traditional single-satellite operation and ground control operation mode has gradually failed to meet the needs of traditional users and enterprises. Multi-connection data mode has become the current development trend.

[0003] Building a distributed Ethernet network based on multiple platforms on board can effectively solve these problems. However, traditional Ethernet networks currently have problems such as data transmission conflicts, which will have a serious impact on the reliability and real-time performance of on-board data transmission.

[0004] Therefore, finding a device and method that can quickly build a highly reliable real-time network on a satellite, which can not only use the resources of the satellite stand-alone platform to quickly and flexibly build a network, but also ensure the reliability and real-time performance of network interactive data transmission has become an urgent problem to be solved today. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a data interaction system for terminal node devices in a satellite-borne real-time network. Through the system, the construction of a satellite-borne high-speed real-time network has better flexibility, and at the same time, the data interaction of the satellite-borne real-time network has real-time, deterministic and high reliability.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0007] A device and design method for a satellite-borne high-reliability real-time network end node device, the device is integrated into a field programmable gate array (FPGA) in the form of an end node IP core; the IP core is a logic block set on the end node device, and the IP core includes an external interface and an internal functional layer;

[0008] The internal functional layer includes a timestamp processing layer, an arrival time scheduling layer and a departure time scheduling layer, a destination query and redundancy elimination layer, and a switching layer;

[0009] The external interface includes a host port, a synchronization port and a plurality of data ports.

[0010] Further, the host port and the synchronization port of the end node device send data frames to the IP core, and the data frames are successively sent from the data port to other network devices after passing through the timestamp processing layer, the arrival time scheduling and departure time scheduling layer, the destination query and redundancy elimination layer, the switching layer, the destination query and redundancy elimination layer, the arrival time scheduling and departure time scheduling layer, and the timestamp processing layer;

[0011] The data port of the end node device receives the data frames sent by other network devices, and the data frames are successively passed through the timestamp processing layer, the arrival time scheduling and departure time scheduling layer, the destination query and redundancy elimination layer, the switching switch layer, the destination query and redundancy elimination layer, the arrival time scheduling and departure time scheduling layer and the timestamp processing layer, and then are given to the host port or the synchronization port of the current end node device.

[0012] Further, the timestamp processing layer is used for periodic time synchronization of each of the end node devices in the global network of the onboard real-time network, tracks the transparent clock field of the protocol control frame PCF received by the IP core, and superimposes the transmission delay on the transmission path of the protocol control frame PCF to achieve synchronization of the global network, specifically:

[0013] The data frame passes through the timestamp processing layer twice from entering the IP core to being output from the IP core;

[0014] When the data frame enters the timestamp processing layer, if the frame type identifier determines that the frame type of the data frame is the protocol control frame PCF, the virtual link ID of the protocol control frame PCF is recorded and the resident delay counter is started, and the protocol control frame PCF is output to the arrival time scheduling and departure time scheduling layer at the same time;

[0015] When the protocol control frame PCF is output from the IP core, it enters the timestamp processing layer again, calculates the counting result of the resident delay counter according to the frame identification and tracking results, and uses the point-to-point time measurement protocol to superimpose the resident time of the protocol control frame PCF in the IP core onto the transparent clock field of the PCF frame, thereby completing the timestamp marking function.

[0016] Furthermore, the PCF frame is a protocol control frame for time synchronization specified by the AS6802 protocol. When its type field is 0x891d, the frame type identifier identifies the protocol control frame PCF; the transparent clock is essentially the delay experienced by the protocol control frame PCF in the real-time network from a synchronization terminal (SM or SC) to a designated switch. When the PCF frame passes through each network device, its transparent clock field is modified to improve the accuracy of the network clock synchronization calculation.

[0017] Furthermore, four types of service data frames are defined on the data transmission network, namely the PCF frame, TT frame, RC frame, and BE frame. Among the data frames of these four service types, the PCF frame is used for network time synchronization and is a periodically transmitted frame; the TT frame, RC frame, and BE frame are used to carry service data with different requirements and are non-periodically transmitted frames; based on the premise of full network time synchronization, a complete time scheduling table is defined as a periodically planned table. In the time scheduling table, except for the PCF frame time slot which is a fixed-length time slot, the TT frame time slot, the RC frame time slot, and the BE frame time slot are all variable-length time slots. The transmission time slot of each service is globally and uniformly planned by the distributed network system according to the application layer data transmission requirements.

[0018] Further, the arrival time scheduling and departure time scheduling layer includes two independent channels of arrival time scheduling and departure time scheduling, specifically: the arrival time scheduling inputs the data processed by the previous timestamp processing layer into the arrival time scheduling channel of this layer, determines the service type of the current data frame by identifying the virtual link ID of the MAC field of the data frame, sends the data of this frame in the time slot corresponding to the service type according to the time scheduling table, and enters the next level destination query and redundancy elimination layer;

[0019] The departure time scheduling is to process the data output from the IP core, and its previous stage is the destination query and the redundancy elimination layer, and the latter stage is the timestamp processing layer; by identifying the virtual link ID of the MAC field of the data frame, the service type of the current data frame is determined, and the frame data is sent to the timestamp processing layer or discarded in the time slot corresponding to the service type according to the time scheduling table;

[0020] Furthermore, the time scheduling table is configured in an open state and a closed state. In the open state, the data frame will be transmitted from the arrival time scheduling layer or the departure scheduling layer to the next processing layer. In the closed state, the data frame will be discarded at the arrival time scheduling layer or the departure time scheduling layer.

[0021] Furthermore, the destination query and redundancy elimination layer includes two independent channels, namely, destination query and redundancy elimination; the destination query and redundancy elimination layer stores a switching forwarding lookup table of the entire device system, in which a one-to-one mapping relationship between each virtual link ID number and a switching port number is recorded;

[0022] The purpose query is to query the MAC field virtual link ID number of the data frame to match the switch port number in the switch forwarding lookup table, obtain the switch port forwarding parameter, and send the data frame and the switch port forwarding parameter to the next level switch layer at the same time;

[0023] The redundant elimination, when the data frame of the data port enters the destination query and redundant elimination layer of the IP core, the redundant elimination function is started, and the redundant data frames of multiple data channels are eliminated, that is, in each time synchronization integration cycle, only the data frames with the same serial number are allowed to pass through once, following the first-come-first-served principle, and the subsequent data frames with duplicate frame identification IDs are eliminated.

[0024] Furthermore, at the switching layer, when the data frame enters the switching layer, the switching port channel will identify the switch of the switching channel data according to the switching port forwarding parameters, identify the destination of the data frame, and send the data frame to the designated port.

[0025] Furthermore, the host port serves as the data source and destination port of the end node device and has the ability to process the data frames of the network; the synchronization port serves as the data source and synchronization port of the end node device and can process the time synchronization protocol, provide a time reference for the operation of the scheduling table, and complete network time synchronization; the data port is connected to other network devices through a physical interface to form multiple data channels, and together with the end node device, constitutes a complete network data transmission and reception.

[0026] Further, the application interaction device is a terminal device for transmitting business data, connected to the host port of the end node device, and used for sending and receiving business data;

[0027] The synchronous SM / SC device is a time synchronization terminal of a real-time network, connected to the synchronization port of the end node device, and used to send and receive the PCF data frame used for network time synchronization;

[0028] The other network device is connected to the data port of the end node device to complete data transmission.

[0029] Compared with the prior art, the present invention has the following technical effects:

[0030] The advantages of the present invention are mainly to provide a data interaction system for the end node equipment of the satellite real-time network to meet the complex data interaction requirements on the satellite. The design of the general architecture facilitates the realization of the synchronization function of the satellite real-time network end system and the construction of a redundant network. According to the needs of actual applications, different functional IPs can be used to quickly realize the construction and data transmission of satellite high-reliability real-time network end nodes, so that the interaction of satellite high-reliability real-time network data is real-time, deterministic and highly reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0032] Figure 1 It is a schematic diagram of a data interaction system of a terminal node device in a satellite-borne real-time network of the present invention;

[0033] Figure 2 It is a functional structure block diagram of the satellite-borne real-time network end node IP core of the present invention;

[0034] Figure 3 This is a working principle diagram of the satellite-borne real-time network end node IP core of the present invention;

[0035] Figure 4 This is a schematic diagram of the onboard real-time network transparent clock transmission of the present invention;

[0036] Figure 5 It is a schematic diagram of time slot division of the onboard real-time network based on global time scheduling of the present invention;

[0037] Figure 6 It is a structural block diagram of the satellite-borne real-time network switching engine module of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the following will describe in detail the design method of a satellite-borne time-triggered network task planning tool provided by the present invention in combination with the drawings in the embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and specific operation process are given.

[0039] Example 1

[0040] The present invention provides a device and a design method for a satellite-borne high-reliability real-time network end node device, wherein the device is integrated into a field programmable gate array (FPGA) in the form of an end node IP core; the IP core is a logic block arranged on the end node device, including an external interface and an internal functional layer.

[0041] The external interface of the IP core includes a host port, a synchronization port and several data ports. The external port is connected to the application interaction device, the synchronization SM / SC device and the other network devices. The device diagram of the end node device is as shown in FIG. Figure 1 As shown:

[0042] The host port serves as the data source and destination port of the end node device, has the data frame processing capability of the network, is connected to the application interaction device, and is mainly used to receive and send service data;

[0043] The synchronization port, as the data source and synchronization port of the end node device, can process the time synchronization protocol, provide a time reference for the operation of the schedule table, complete network time synchronization, connect with the synchronous SM / SC device, and be used to send and receive the PCF data frame used for network time synchronization;

[0044] The data port is connected to other network devices through a physical interface to form multiple data channels, complete the corresponding data transmission, and together with the end node device, form a complete network data reception and transmission.

[0045] The IP core includes a timestamp processing layer, an arrival time scheduling layer and a departure time scheduling layer, a destination query and redundancy elimination layer, and a switching layer according to the internal functional layer. The functional structure diagram of the IP core is as follows: Figure 2 shown.

[0046] The host port and the synchronization port of the end node device send data frames to the IP core, and the data frames are successively sent from the data port to other network devices after passing through the timestamp processing layer, the arrival time scheduling and departure time scheduling layer, the destination query and redundancy elimination layer, the switching layer, the destination query and redundancy elimination layer, the arrival time scheduling and departure time scheduling layer, and the timestamp processing layer;

[0047] The data port of the end node device receives the data frame sent by other network devices, and the data frame is successively passed through the timestamp processing layer, the arrival time scheduling and departure time scheduling layer, the destination query and redundancy elimination layer, the switching layer, the destination query and redundancy elimination layer, the arrival time scheduling and departure time scheduling layer and the timestamp processing layer, and then is given to the host port or the synchronization port of the current end node device. The working principle of the IP core is as follows Figure 3 shown.

[0048] Furthermore, in this embodiment, for the timestamp processing layer.

[0049] The timestamp processing layer is used for periodic time synchronization of each end node device in the global network of the satellite-borne real-time network. It tracks the transparent clock field of the protocol control frame PCF received by the IP core, superimposes the transmission delay on the transmission path of the protocol control frame PCF, and realizes the specific synchronization position of the global network.

[0050] The high-reliability real-time network involved in the present invention is embodied in the time synchronization of the network. The network time synchronization function is mainly implemented through the protocol control frame PCF defined in the SAE AS6802 protocol. The protocol control frame PCF frame is periodically exchanged between network devices to achieve time synchronization of the global network.

[0051] The frame content mainly includes the following key parameters: integration cycle, membership vector, synchronization priority, synchronization domain, frame type, transparent clock, etc.

[0052] When the type field of the frame is 0x891d, the frame type identifier identifies the protocol control frame PCF; the transparent clock is essentially the delay experienced by the protocol control frame PCF in the real-time network from a synchronization terminal (SM or SC) to a designated port. When the PCF frame passes through each network device, its transparent clock field is modified to improve the accuracy of the network clock synchronization calculation.

[0053] The PCF frame will modify its transparent clock field each time it passes through a network device, that is, the residence time in the network device is added to the field to improve the accuracy of network clock synchronization calculation.

[0054] In the design of this end system, a data frame will pass through the timestamp processing layer twice from entering the end system IP to being output from the end system IP. The timestamp processing layer only tracks the PCF frame. When the data frame enters the timestamp processing layer, the frame type identifier will identify the frame type field of the data frame. When the frame type field is OX891d, it means that the data frame is the PCF frame. Then the virtual link ID of the frame is recorded and the resident delay counter is started, the transparent clock is updated, and the timestamp is added to the data frame. At the same time, the PCF frame is output to the next level of the arrival time scheduling and departure time scheduling layer.

[0055] When the PCF frame is to be output from the end system IP, it will enter the timestamp processing layer again. At this time, based on the frame identification and tracking results, the point-to-point time measurement protocol is used to calculate the counting result of the residence delay counter, and the residence time of the PCF frame in the end system IP is superimposed on the transparent clock field of the PCF frame to complete the timestamp marking function.

[0056] Furthermore, in this embodiment, for the arrival time scheduling and departure time scheduling layers.

[0057] In the design of this end system, four types of service data frames are defined on the data transmission network, namely the PCF frame, TT frame, RC frame, and BE frame. Among the data frames of these four service types, the PCF frame is used for network time synchronization and is a periodically transmitted frame; the TT frame, RC frame, and BE frame are used to carry service data with different requirements and are non-periodically transmitted frames; based on the premise of full network time synchronization, a complete time scheduling table is defined as a periodically planned table. In the time scheduling table, except for the PCF frame time slot which is a fixed-length time slot, the TT frame time slot, the RC frame time slot, and the BE frame time slot are all variable-length time slots. The transmission time slot of each service is globally and uniformly planned by the distributed network system according to the application layer data transmission requirements.

[0058] The arrival time scheduling and departure time scheduling layer includes two independent channels, arrival time scheduling and departure time scheduling, specifically: the arrival time scheduling inputs the data processed by the previous timestamp processing layer into the arrival time scheduling channel of this layer, determines the service type of the current data frame by identifying the virtual link ID of the MAC field of the data frame, sends the data of this frame in the time slot corresponding to the service type according to the time scheduling table, and enters the next level destination query and redundancy elimination layer. .

[0059] The departure time scheduling is to process the data output from the IP core. Its predecessor is the destination query and the redundant elimination layer, and the latter is the timestamp processing layer. By identifying the virtual link ID of the MAC field of the data frame, the service type of the current data frame is determined, and the frame data is sent to the timestamp processing layer or discarded in the time slot corresponding to the service type according to the time scheduling table.

[0060] The time scheduling table is configured in an open state and a closed state. In the open state, the data frame will be transmitted from the arrival time scheduling layer or the departure time scheduling layer to the next processing layer. In the closed state, the data frame will be discarded at the arrival time scheduling layer or the departure time scheduling layer.

[0061] Furthermore, in this embodiment, the target query and redundant elimination layers are performed.

[0062] The destination query and redundancy elimination layer includes two independent channels, destination query and redundancy elimination, to realize the port forwarding parameter query of data exchange and the redundant data frame elimination function of multiple data channels;

[0063] The destination query queries the port forwarding parameters of the switch after the data frame enters the destination query and redundancy elimination layer, and sends the data frame and the switch port forwarding parameters to the next level switch layer at the same time.

[0064] The redundant elimination, when the data frame of the data port enters the destination query of the IP core, the redundant elimination function is started, and the redundant data frames of multiple data channels are eliminated, that is, only the data frames with the same serial number are allowed to pass through once, following the first-come-first-served principle, and the subsequent data frames with duplicate frame identification IDs are eliminated.

[0065] For the destination query, no matter the data frame enters the IP core from the host port, the synchronization port or the data port, this function will be started when entering the destination query and redundancy elimination layer.

[0066] The data transmission designed in this system adopts the network data exchange based on virtual link.

[0067] The allocation of virtual link IDs is globally planned by the distributed network system. The virtual link ID is located in the MAC destination address field of the network data frame, and the format is shown in Table 1.

[0068] Table 1 MAC destination address format

[0069]

[0070] The upper 32 bits are constant fields, and the lower 16 bits are virtual link IDs. Each different type of data frame has a unique virtual link ID.

[0071] The destination query and redundancy elimination layer stores the switching forwarding lookup table of the entire end system, and the lookup table records the one-to-one mapping relationship between each virtual link ID number and the switching port number.

[0072] When the data frame enters the destination query and redundancy elimination layer of the IP core, the destination query function is started. After extracting the virtual link ID of the MAC field of the data frame, it is searched and matched with the information in the forwarding lookup table to obtain the switching port forwarding parameter tdest, and then the data frame and the switching port forwarding parameter tdest are sent to the next-level switching switch layer at the same time.

[0073] The destination query layer of the host port copies multiple data frame types to all data ports to achieve redundant transmission; the destination query layer of the data port forwards the data frame type to the host port or the synchronization port.

[0074] For the redundancy elimination, this function is enabled only for the data frame entering the IP core from the data port.

[0075] The IP core has a plurality of data ports, and the redundant backup function of the data channel can be realized by interconnecting the plurality of data channels with different network switching devices.

[0076] When multiple data channels can transmit data normally, the IP core needs to perform overall detection on the data from different data channels, follow the first-come-first-served principle, and remove the redundant data frames, i.e., the data frames with duplicate frame identification IDs.

[0077] Redundancy elimination is performed based on the frame identification ID and channel identification ID of the data frame.

[0078] The frame identification ID and channel identification ID are defined in the MAC source address field of the network data frame, and the format is shown in Table 2.

[0079] Table 2 MAC source address format

[0080]

[0081] The frame ID is 8 bits wide. In each time synchronization integration cycle of the highly reliable real-time network, the frame ID of each data frame is a unique value. The channel ID is 3 bits wide. Each channel ID number has a one-to-one mapping relationship with multiple data channels of the end system.

[0082] When the data frame from the data channel enters the destination query and redundancy elimination layer of the IP core, the redundancy elimination function is started. After extracting the frame identification ID and channel identification ID of the data frame MAC field, the redundancy elimination algorithm is executed. In each time synchronization integration cycle, only data frames carrying the same frame identification ID are allowed to be received once. Following the first-come-first-served principle, subsequent data frames with duplicate frame identification IDs are eliminated.

[0083] Furthermore, in this embodiment, for the exchange switch layer.

[0084] The switching layer implements data interaction control between all external interface channels of the end system IP.

[0085] The core of the switching layer is the switching engine module, which adopts a typical packet switching structure with a lookup table. It controls the transmission switch of each switching channel data through the switching port forwarding parameter tdest to realize the network packet switching function of different types of data.

[0086] The main components of the switching engine module include input buffer (Inbound Buffer), crosspoint buffer (Crosspoint Buffer), and output buffer (Outbound Buffer). Through the coordinated work of each level of buffer, the switching engine module supports fast replication and parallel forwarding of data frames. The structural block diagram is as follows Figure 5 shown.

[0087] When a data frame enters the switching layer, the previous destination query and redundancy elimination layer will simultaneously give the switching port forwarding parameter tdest. tdest is a multi-bit semaphore. Each bit is mapped one-to-one with each switching port channel. The signal of the switching port is used to control the transmission switch of each switching channel data, identify the destination of the data frame, and then send the data frame to the designated port. When the bit is '1', it means that the corresponding switching port channel is open, and the data frame will be output from the current port channel; when the bit is '0', it means that the corresponding switching port channel is closed, and the data frame will not be output from the current port channel; when multiple bits are '1' at the same time, the data frame will be output from the open port channel at the same time.

[0088] When the data frame enters the switching switch layer, the switching port channel will identify the switch of the switching channel data according to the switching port forwarding parameter tdest, identify the destination of the data frame, and send the data frame to the designated port. The switching port forwarding parameter tdest is a multi-bit semaphore, and the specific operation is as follows: when the bit is '1', it means that the current switching port channel is open, and the data frame will be output from the current port channel; when the bit is '0', it means that the current switching port channel is closed, and the data frame will not be output from the current port channel; when multiple bits are '1' at the same time, it means that multiple corresponding switching ports are open, and the data frame will be output from the open port channels at the same time.

[0089] The above disclosure is only a specific embodiment of the present application, but the present application is not limited thereto. Any changes that can be conceived by technicians in this field should fall within the protection scope of the present application.

Claims

1. A data interaction system for a mid-terminal node device in a satellite-borne real-time network, characterized in that: include: IP core, the IP core is a logic block provided on the end node device; The IP core includes an external interface and an internal functional layer; The internal functional layer includes a timestamp processing layer, an arrival time scheduling layer and a departure time scheduling layer, a destination query and redundancy elimination layer, and an exchange switch layer; The external interface includes a host port, a synchronization port and a plurality of data ports; The host port and the synchronization port of the end node device send data frames to the IP core, and the data frames are successively sent from the data port to other network devices after passing through the timestamp processing layer, the arrival time scheduling and departure time scheduling layer, the destination query and redundancy elimination layer, the switching layer, the destination query and redundancy elimination layer, the arrival time scheduling and departure time scheduling layer, and the timestamp processing layer; The data port of the end node device receives the data frame sent by other network devices, and the data frame is successively passed through the timestamp processing layer, the arrival time scheduling and departure time scheduling layer, the destination query and redundancy elimination layer, the switching layer, the destination query and redundancy elimination layer, the arrival time scheduling and departure time scheduling layer and the timestamp processing layer, and then is given to the host port or the synchronization port of the current end node device; Among them, after the timestamp processing layer performs frame identification and tracking on the data frame, the MAC field virtual link ID of the data frame is identified through the arrival time scheduling channel of the arrival time scheduling and departure time scheduling layer, and the data frame data is sent to the destination query and redundancy elimination layer in the time slot corresponding to the service type of the data frame according to the time scheduling table, and the port forwarding parameters of the data frame after the destination query and redundancy elimination are obtained. After the transmission switch of each switching channel data is controlled through the switching switch layer based on the port forwarding parameters, after the destination query of the destination query and redundancy elimination layer, the MAC field virtual link ID is identified through the departure time scheduling channel of the arrival time scheduling and departure time scheduling layer, and then the data frame data is sent to the timestamp processing layer or discarded.

2. A data interaction system for a terminal node device in a satellite-borne real-time network according to claim 1, characterized in that: The timestamp processing layer is used for periodic time synchronization of each of the end node devices in the global network of the onboard real-time network, tracks the transparent clock field of the PCF frame received by the IP core, and superimposes the transmission delay on the transmission path of the PCF frame to achieve synchronization of the global network, specifically: The data frame passes through the timestamp processing layer twice from entering the IP core to being output from the IP core; When the data frame enters the timestamp processing layer, if the frame type identifier determines that the frame type of the data frame is the PCF frame, the virtual link ID of the PCF frame is recorded and the resident delay counter is started, and the PCF frame is output to the arrival time scheduling and departure time scheduling layers; When the PCF frame is output from the IP core, it enters the timestamp processing layer again, calculates the counting result of the resident delay counter according to the frame identification and tracking results, and uses the point-to-point time measurement protocol to superimpose the resident time of the PCF frame in the IP core onto the transparent clock field of the PCF frame, thereby completing the timestamp marking function.

3. A data interaction system for a terminal node device in a satellite-borne real-time network as claimed in claim 2, characterized in that: The data frames include four service types, namely, the PCF frame, the TT frame, the RC frame and the BE frame. Among the data frames of the four service types, the PCF frame is used for network time synchronization and is a periodically transmitted frame; the TT frame, the RC frame and the BE frame are used to carry service data with different requirements and are non-periodically transmitted frames; based on the premise of full network time synchronization, a complete time scheduling table is defined as a periodically planned table. In the time scheduling table, except for the PCF frame time slot which is a fixed-length time slot, the TT frame time slot, the RC frame time slot and the BE frame time slot are variable-length time slots. The transmission time slot of each service is globally and uniformly planned by the distributed network system according to the application layer data transmission requirements.

4. A data interaction system for a terminal node device in a satellite-borne real-time network as claimed in claim 3, characterized in that: The arrival time scheduling and departure time scheduling layer includes two independent channels of arrival time scheduling and departure time scheduling, specifically: The arrival time scheduling inputs the data processed by the previous timestamp processing layer into the arrival time scheduling channel of this layer, determines the service type of the current data frame by identifying the virtual link ID of the MAC field of the data frame, sends the data of this frame in the time slot corresponding to the service type according to the time scheduling table, and enters the next level destination query and redundancy elimination layer; The departure time scheduling is to process the data output from the IP core. Its predecessor is the destination query and the redundant elimination layer, and the latter is the timestamp processing layer. By identifying the virtual link ID of the MAC field of the data frame, the service type of the current data frame is determined, and the frame data is sent to the timestamp processing layer or discarded in the time slot corresponding to the service type according to the time scheduling table.

5. A data interaction system for a terminal node device in a satellite-borne real-time network as claimed in claim 4, characterized in that: The time scheduling table is configured in an open state and a closed state. In the open state, the data frame will be transmitted from the arrival time scheduling layer or the departure time scheduling layer to the next processing layer. In the closed state, the data frame will be discarded at the arrival time scheduling layer or the departure time scheduling layer.

6. A data interaction system for a terminal node device in a satellite-borne real-time network as claimed in claim 5, characterized in that: The target query and redundancy elimination layer includes two independent channels, the target query and the redundancy elimination; The destination query and redundancy elimination layer stores the switching forwarding lookup table of the entire device system, and the lookup table records the one-to-one mapping relationship between each virtual link ID number and the switching port number; The purpose query is to query the MAC field virtual link ID number of the data frame to match the switch port number in the switch forwarding lookup table, obtain the switch port forwarding parameter, and send the data frame and the switch port forwarding parameter to the next level switch layer at the same time; The redundant elimination, when the data frame of the data port enters the destination query and redundant elimination layer of the IP core, the redundant elimination function is started, and the redundant data frames of multiple data channels are eliminated, that is, in each time synchronization integration cycle, only the data frames with the same serial number are allowed to pass through once, following the first-come-first-served principle, and the subsequent data frames with duplicate frame identification IDs are eliminated.

7. A data interaction system for a terminal node device in a satellite-borne real-time network as claimed in claim 6, characterized in that: The switching layer, when the data frame enters the switching layer, the switching port channel will identify the switch of the switching channel data according to the switching port forwarding parameters, identify the destination of the data frame, and send the data frame to the designated port.

8. A data interaction system for a terminal node device in a satellite-borne real-time network as claimed in claim 7, characterized in that: The external interface includes a host port, a synchronization port and a plurality of data ports; The host port serves as the data source and destination port of the end node device and has the data frame processing capability in the network; The synchronization port serves as the data source and synchronization port of the end node device, processes the time synchronization protocol, provides a time reference for the operation of the scheduling table, and completes network time synchronization; The data port is connected to other network devices through a physical interface to form multiple data channels, and together with the end node device, it constitutes a complete network data transmission and reception.

9. A data interaction system for a terminal node device in a satellite-borne real-time network as claimed in claim 8, characterized in that: The external interface is connected to the application interaction device, the synchronous SM / SC device, and the other network devices; The application interaction device is a terminal device for transmitting service data, connected to the host port of the end node device, and used for sending and receiving service data; The synchronous SM / SC device is a time synchronization terminal of a real-time network, connected to the synchronization port of the end node device, and used to send and receive the PCF data frame used for network time synchronization; The other network device is connected to the data port of the end node device to complete data transmission.

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