A dual-network redundant transmission method and device based on link selection

Abstract

The application discloses a double-network redundancy transmission method and device based on link selection, and the method comprises the following steps: a data sending node duplicates message data and sends the message data to two independent parallel transmission networks through two network cards; when the data receiving node receives the message data sent by the data sending node from the corresponding transmission network through any one of the two network cards, the data receiving node checks a built-in node link state table, judges whether the record of the data sending node exists, if the record exists, judges whether the message data is sent according to the record of the data sending node, and updates the record of the data sending node in the node link state table according to the message data; if the record does not exist, the record of the data sending node is added in the node link state table, and the message data is sent according to the record of the data sending node; the application can construct two physically completely independent networks, and data can be transparently, efficiently and reliably transmitted in the two networks.

Description

TECHNICAL FIELD

[0001] The application relates to a dual-network redundancy transmission method and device based on link selection and belongs to the technical field of computer networks. BACKGROUND

[0002] The dispatching automation master station system is a core support system for power grid operation control and dispatching production management. In the latest revised safety accident investigation regulations of State Grid Corporation of China, the complete failure of the SCADA function of the main dispatching system of the power monitoring system with a safety protection level of four is listed as a level six equipment event, which puts forward higher requirements for the reliability of the power monitoring system. The reliability of the network as the basis for the operation of the dispatching automation master station system will directly affect the reliability of the master station system.

[0003] At present, the dispatching automation master station system network mainly adopts the mode of node redundancy, network card redundancy and switch redundancy interconnection. Any single point failure in the network will not affect the normal operation of the system. However, in recent years, with the improvement of the intelligence of the switch, the complexity of the redundant interconnection between switches has also increased, and some software and hardware failures of the switch may cause the overall failure of a group of switches in mutual redundancy. For example, the heartbeat line failure between switches adopting VRRP redundancy configuration will cause double master failure of the switches, and for example, repeated abnormalities of some boards of switches adopting stacking configuration may cause abnormal stacking state. The overall failure of such interconnected switches will affect the underlying network topology of the dispatching automation master station system, which may cause partial business systems to fail to operate normally, or even cause the entire business system to completely fail. SUMMARY

[0004] The application aims to overcome the deficiencies in the prior art, provide a dual-network redundancy transmission method and device based on link selection, solve the problems exposed in the network architecture of the existing dispatching automation master station system with multiple devices and a single network, and through the construction of two physically completely independent networks, data can be transparently, efficiently and reliably transmitted in the two networks, thus getting rid of the dependence on switch interconnection in the past and solving the problem of network paralysis caused by switch interconnection failure.

[0005] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0006] In a first aspect, the application provides a dual-network redundancy transmission method based on link selection, comprising:

[0007] The data sending node replicates the message data and sends them to two independent parallel transmission networks through two network cards respectively;

[0008] When the data receiving node receives the packet data sent by the data sending node through any one of the two network cards from the corresponding transmission network, the built-in node link state table is checked to determine whether the record of the data sending node exists,

[0009] If the record exists, it is determined whether to send the packet data according to the record of the data sending node, and the record of the data sending node is updated in the node link state table according to the packet data;

[0010] If the record does not exist, the record of the data sending node is added to the node link state table, and the packet data is sent according to the record of the data sending node;

[0011] The two network cards corresponding to the data sending node have the same MAC address and IP address, and the two network cards corresponding to the data receiving node have the same MAC address and IP address.

[0012] Optionally, the record of the data sending node includes the IP address of the data sending node, the on-duty link, the latest packet time of the on-duty link and the standby link.

[0013] The IP address of the data sending node is used as an index.

[0014] The network card of the data receiving node that first receives the packet data from the data sending node and the corresponding transmission network thereof are set as the on-duty link of the data sending node, and the time when the network card receives the packet data is set as the latest packet time of the on-duty link. The other network card of the data receiving node and the corresponding transmission network thereof are set as the standby link of the data sending node, and the latest packet time of the standby link is preset to 0.

[0015] Optionally, the determination of whether the record of the data sending node exists includes searching for whether the record of the data sending node exists through the index.

[0016] The record of the data sending node is updated in the node link state table according to the packet data.

[0017] The record of the corresponding data sending node is searched for according to the IP address of the data sending node.

[0018] The latest packet time of the on-duty link or the standby link corresponding to the network card of the data receiving node is updated according to the time when the network card receives the packet data.

[0019] Optionally, the determination of whether to send the packet data according to the updated record of the data sending node includes sending the packet data if the packet data is from the on-duty link, and discarding the packet data if the packet data is from the standby link.

[0020] The sending message data on the record of the data sending node comprises sending message data from the on-duty link.

[0021] Optionally, the data receiving node monitors the records of each data sending node in the built node link state table according to a preset period, and judges whether to switch the on-duty link and the standby link of the corresponding data sending node; the process is as follows:

[0022] It is judged whether the difference between the latest message time of the on-duty link and the current system time is greater than two periods, if yes, the next step is entered; if not, the switching is not performed and the delay waiting period is cleared;

[0023] It is judged whether the difference between the latest message time of the standby link and the current system time is greater than two preset periods, if yes, the switching is not performed and the delay waiting period is cleared; if not, the next step is entered;

[0024] It is judged whether the current system time is in the delay waiting period, if yes, the on-duty link and the standby link are switched, the link switching alarm is triggered, and the delay waiting period is cleared; if not, the delay waiting period is entered, and the above steps are repeated;

[0025] The delay waiting period is one period.

[0026] Optionally, the message time and the system time are recorded by using the jiffies global variable of the operating system.

[0027] Optionally, the data receiving node acquires the fault information of the self network card in real time, and judges whether to switch the on-duty link and the standby link of the corresponding data sending node; the process is as follows:

[0028] It is judged whether the data receiving node receives the fault information of the self network card, if yes, the network card fault alarm is triggered;

[0029] According to the fault information, the node link state table is traversed, it is judged whether the fault network card has a corresponding on-duty link, if yes, the data sending node corresponding to the on-duty link is acquired, and the on-duty link and the standby link of the data sending node are switched and the link switching alarm is triggered.

[0030] In the second aspect, the application discloses a dual-network redundancy transmission device based on link selection, characterized in that the device comprises two transmission networks and at least two dual-network card nodes, the two transmission networks are independent and parallel; the dual-network card node comprises two network cards, and the dual-network card node is connected to the two transmission networks through the two network cards; when the two dual-network card nodes are used as a data sending node and a data receiving node respectively, the message data is transmitted through the dual-network redundancy transmission method based on link selection according to any one of claims 1-7.

[0031] The two network cards corresponding to the data sending node have the same MAC address and IP address; the two network cards corresponding to the data receiving node have the same MAC address and IP address.

[0032] Optionally, the dual-network redundancy transmission device further comprises a single-network-card node, the single-network-card node comprising one network card, and the single-network-card node being connected to any transmission network through the network card;

[0033] When the single-network-card node acts as a data sending node, the data sending node sends message data to the corresponding transmission network through the network card, and the data receiving node receives the message data through the network card corresponding to the transmission network and sends the message data to the upper layer, thereby completing message data transmission.

[0034] When the single-network-card node acts as a data receiving node, the data receiving node receives the message data sent by the data sending node from the corresponding transmission network through the network card and sends the message data to the upper layer, thereby completing message data transmission.

[0035] Optionally, when the single-network-card node acts as a data sending node, the data receiving node acquires real-time network card fault information and triggers network card fault alarm based on the network card fault information.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] The dual-network redundancy transmission method and device based on link selection provided by the present application are free from dependence on switch interconnection, data is transmitted on two completely independent links, the receiving end sends data on one link according to the link state, and any network N-1 failure can be resisted. The method has simple logic and good data transmission performance, does not modify the message, has strong device adaptability, and is transparent to the application and does not need to modify the application program. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a dual-network redundancy transmission method flowchart provided by an embodiment of the present application based on link selection;

[0039] Figure 2 is a periodic detection flowchart of the on-duty link and the standby state provided by an embodiment of the present application;

[0040] Figure 3 is a dual-network redundancy connection schematic diagram provided by an embodiment of the present application based on link selection;

[0041] Figure 4 is an interaction flowchart of the data receiving node and the data receiving node provided by an embodiment of the present application;

[0042] Figure 5This is a schematic diagram of a dual-network redundant transmission device based on link selection provided in an embodiment of the present invention. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0044] Example 1:

[0045] like Figure 1 As shown, this embodiment of the invention provides a dual-network redundancy transmission method based on link selection, including:

[0046] The data sending node copies the message data and sends it to two independent parallel transmission networks through two network interface cards;

[0047] When a data receiving node receives a message from a data sending node through either of its two network interface cards (NICs) in the corresponding transmission network, it checks its built-in node link state table to determine if a record of the data sending node exists.

[0048] If it exists, determine whether to send message data based on the record of the data sending node, and update the record of the data sending node in the node link state table according to the message data;

[0049] If it does not exist, add a record of the data sending node to the node link status table, and send the message data according to the record of the data sending node;

[0050] In this configuration, the two network interface cards (NICs) corresponding to the data sending node have the same MAC address and IP address; the two NICs corresponding to the data receiving node have the same MAC address and IP address.

[0051] Specifically:

[0052] (1) The records of the data sending node include the IP address of the data sending node, the latest message time of the standby link, the standby link and the backup link;

[0053] Indexed by the IP address of the data sending node;

[0054] The network interface card (NIC) of the data receiving node that first receives message data from the data sending node and its corresponding transmission network are designated as the standby link of the data sending node, and the time when the NIC receives the message data is designated as the latest message time of the standby link; the other NIC of the data receiving node and its corresponding transmission network are designated as the backup link of the data sending node, and the latest message time of the backup link is preset to 0.

[0055] (2) judging whether the record of the data sending node exists includes judging whether the record of the data sending node exists through index searching;

[0056] updating the record of the data sending node in the node link state table according to the message data includes:

[0057] index searching the record of the corresponding data sending node according to the IP address of the data sending node;

[0058] updating the latest message time of the corresponding on-duty link or standby link of the network card according to the time when the network card of the data receiving node receives the message data.

[0059] (3) judging whether to send the message data according to the updated record of the data sending node includes: if the message data comes from the on-duty link, sending the message data; if the message data comes from the standby link, discarding the message data;

[0060] sending the message data according to the record of the data sending node includes: sending the message data from the on-duty link.

[0061] (4) as shown in Figure 2 , the data receiving node monitors the records of each data sending node in the built-in node link state table according to a preset period, and judges whether to switch the on-duty link and standby link of the corresponding data sending node; the process is as follows:

[0062] judging whether the difference between the latest message time of the on-duty link and the current system time is greater than two periods, if yes, going to the next step; if no, not switching and clearing the delay waiting period;

[0063] judging whether the difference between the latest message time of the standby link and the current system time is greater than two preset periods, if yes, not switching and clearing the delay waiting period; if no, going to the next step;

[0064] judging whether the current system time is in the delay waiting period, if yes, switching the on-duty link and standby link, triggering the link switching alarm and clearing the delay waiting period; if no, entering the delay waiting period and repeating the above steps;

[0065] wherein, the delay waiting period is one period.

[0066] In the above, the message time and the system time are recorded by using the jiffies global variable of the operating system.

[0067] (5) the data receiving node acquires the fault information of its own network card in real time, and judges whether to switch the on-duty link and standby link of the corresponding data sending node; the process is as follows:

[0068] judging whether the data receiving node receives the self network card fault information, if yes, triggering the network card fault alarm;

[0069] According to the fault information, the node link state table is traversed, whether the fault network card has a corresponding duty link is judged, if yes, the data sending node corresponding to the duty link is obtained, and the duty link and the standby link of the data sending node are switched and the link switching alarm is triggered.

[0070] According to the fault information, the node link state table is traversed, whether the network card and the transmission network corresponding to the network card are the duty link of any data sending node is judged, if yes, the duty link and the standby link of the data sending node are switched and the link switching alarm is triggered.

[0071] As Figure 3 shown, the embodiment of the application provides a double network redundancy connection schematic diagram based on link selection; in the figure, two independent parallel transmission networks are A network and B network respectively; the access nodes are node S1, node S2 and node S3, node S1 and node S2 access two independent networks A / B through two network cards (Eth0, Eth1) respectively, node S3 accesses one of the networks A through a single network card (Eth0), the IP address of node S1 is 10.0.0.1, the IP address of node S2 is 10.0.0.2, and the IP address of node S3 is 10.0.0.3. S1 is a data receiving node, and S2 and S3 are data sending nodes. The embodiment is further described in combination with the double network redundancy.

[0072] ①, each node updates its own node link state table in real time according to the received message data, and the specific content is that each node maintains a node link state table, which records the link state from other nodes in the local area network to the node. As shown in Table 1, the node link state table of node S1 is shown in Table 1;

[0073] Table 1:

[0074] Node IP Active-Line A-LastActive-LineTime B-LastActive-LineTime 10.0.0.2 Eth0 Jiffies A2 Jiffies B2 10.0.0.3 Eth0 Jiffies A3 0

[0075] The node link state table of node S1 is empty in the initial state;

[0076] When node S1 receives the message data from node S2 for the first time, a record is added in the node link state table of node S1, the record takes the IP address of node S2 as an index, if the message data is received from A network, the latest message time Jiffies A2 of A network is updated, and the network card corresponding to A network is set as the duty link of node S2, at this time, the latest message time of B network is 0. If the message data is received from B network, the latest message time of B network is updated, and the network card of B network is set as the duty link of node S2, at this time, the latest message time of A network is 0.

[0077] When the node S1 receives the message data from the node S2 again, according to the index, the record corresponding to the node S2 is found, and the corresponding latest message time is updated. If the message data is received from the A network, the latest message time of the A network is updated. If the message data is received from the B network, the latest message time of the B network is updated.

[0078] For the first time that the node S1 receives the message data from the node S3, a record is added in the node link state table of the node S1, the record takes the IP address of the node S3 as the index, and the latest message time Jiffies A3 of the A network is updated if the message data is received from the A network, and the corresponding network card of the A network is set as the on-duty link of the node S3.

[0079] When the node S1 receives the message data from the node S3 again, according to the index, the record corresponding to the node S3 is found, and the corresponding latest message time is updated. If the message data is received from the A network, the latest message time of the A network is updated.

[0080] Here, the jiffies global variable of the operating system is used as the message time to prevent time confusion caused by modification of the system time.

[0081] ②、As shown in Figure 4 When the data receiving node receives the message data from the corresponding transmission network through any one of the two network cards, the built-in node link state table is checked to determine whether the record of the data sending node exists,

[0082] If the record exists, the record of the data sending node (the latest message time) is updated in the node link state table, and whether the message data is sent is determined according to the record of the data sending node (the on-duty link). Specifically, if the message data comes from the on-duty link, the message data is sent. If the message data comes from the standby link, the message data is discarded.

[0083] If the record does not exist, the record of the data sending node is added in the node link state table, the network card and the transmission network from which the message data is received are set as the on-duty link, and the message data is sent. Specifically, the message data from the on-duty link is sent.

[0084] ③、The data receiving node monitors the records of each data sending node in the built-in node link state table according to a preset period, and determines whether to switch the on-duty link and the standby link. Specifically,

[0085] Node S1 checks the status of each node in its node link state table periodically (preset period 100 ms) and checks whether any node needs to perform link switching. For node record 10.0.0.2, the value of jiffiesA2 is checked. If the difference between jiffiesA2 and the system jiffies value is greater than 2 periods, the value of jiffiesB2 of the backup link is checked. If the difference between jiffiesB2 and the system jiffies value is also greater than 2 periods, it is considered that no data arrives on both links, which is a normal idle state. If the difference between jiffiesB2 and the system jiffies value is less than or equal to 2 periods, it is suspected that the on-duty link is abnormal, and a delay waiting period is entered.

[0086] In the delay waiting period, if the difference between the value of jiffiesA2 of the on-duty link and the value of jiffiesB2 of the backup link and the system jiffies value is greater than 2 periods, it is considered that the message received by the backup link before is due to the reason that the delay of the backup link is greater than that of the on-duty link, and the two links are actually in a normal idle state. If only the difference between the value of jiffiesA2 of the on-duty link and the system jiffies value is greater than 2 periods, it is considered that the on-duty link is faulty, the on-duty link of 10.0.0.2 in the node link state table is changed to eth1, and a link switching alarm is sent. For node record 10.0.0.3, since S3 is a single network device, no link switching is performed, and if the on-duty link is idle for 3 consecutive periods, it is considered that the link is idle.

[0087] ④, Once a local network card of node S1 has an electrical fault that can be sensed, a network card fault alarm is sent, and all on-duty links involved in the fault in the node link state table and having a backup link are switched in real time, such as the eth0 network card of S1 is faulty, the on-duty link of the 10.0.0.2 record in the node link state table is changed from eth0 to eth1, and a link switching alarm is sent. However, the 10.0.0.3 record is a single node device since the message update time of eth1 is always 0, and no link switching is performed.

[0088] Embodiment Two:

[0089] As shown in Figure 5 The embodiment of the application provides a dual-network redundant transmission device based on link selection, which comprises two transmission networks and at least two dual-network card nodes. The two transmission networks (network A and network B) are independent and parallel. The dual-network card node comprises two network cards, and the dual-network card node is connected to the two transmission networks through the two network cards. When the two dual-network card nodes are respectively used as a data receiving node S1 and a data sending node S2, a message data transmission is performed through the dual-network redundant transmission method based on link selection provided in the embodiment one.

[0090] Wherein, the two network cards corresponding to the data receiving node S1 have the same MAC address and IP address; the two network cards corresponding to the data sending node S2 have the same MAC address and IP address.

[0091] Wherein, the dual-network redundancy transmission device further comprises a single-network card node, the single-network card node comprises one network card, and the single-network card node accesses any transmission network through the network card; specifically,

[0092] When the single-network card node acts as the data sending node S3, the data sending node S3 sends the message data to the corresponding A transmission network through the network card, and the data receiving node S1 receives the message data through the network card corresponding to the A transmission network and performs uploading, thereby completing the message data transmission.

[0093] When the single-network card node acts as the data receiving node S3, the data receiving node S3 receives the message data sent by the data sending node S1 or S2 from the corresponding A transmission network through the network card and performs uploading, thereby completing the message data transmission.

[0094] When the single-network card node acts as the data sending node, the data receiving node acquires the network card fault information in real time and triggers the network card fault alarm based on the network card fault information.

[0095] The dual-network redundancy transmission method and device based on link selection provided by the application provide a transparent, efficient and reliable transmission method of data in two physically independent networks, and break away from the dependence on the interconnection of switches under the original multi-device single-network architecture, thereby solving the network paralysis problem possibly caused by the interconnection fault of switches in the existing dispatching automation master station system.

[0096] Those skilled in the art should understand that the embodiments of the application can be provided as a method, a system, or a computer program product. Therefore, the application can adopt a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the application can adopt the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0097] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0098] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0099] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0100] The above only is the preferred embodiment of the present application, it should be pointed out that, for those skilled in the technical field, without departing from the technical principles of the present application, can also make a number of improvements and variations, these improvements and variations should also be considered as the protection scope of the present application.

Claims

1. A method for dual network redundant transmission based on link selection, characterized in that, The application relates to a data transmission method and device. The data sending node duplicates message data and sends the message data to two independent parallel transmission networks through two network cards respectively; When the data receiving node receives the message data sent by the data sending node through any one of the two network cards, the data receiving node checks a built-in node link state table to determine whether the data sending node record exists, If the data sending node record exists, whether the message data is uploaded is determined according to the data sending node record, and the data sending node record is updated in the node link state table according to the message data; wherein the updating comprises updating the latest message time of the corresponding primary link and standby link; If the data sending node record does not exist, the data sending node record is added in the node link state table, and the message data is uploaded according to the data sending node record; The two network cards corresponding to the data sending node have the same MAC address and IP address; the two network cards corresponding to the data receiving node have the same MAC address and IP address; The network card of the data receiving node which first receives the message data from the data sending node and the corresponding transmission network are set as the primary link of the data sending node, and the other network card of the data receiving node and the corresponding transmission network are set as the standby link of the data sending node; The data receiving node monitors the records of each data sending node in the built-in node link state table according to a preset period, and determines whether to switch the primary link and standby link of the corresponding data sending node; the process is as follows: Step S1, determining whether the difference between the latest message time of the primary link and the current system time is greater than two periods, if yes, the next step is entered; if no, the switching is not performed and the delay waiting period is cleared; Step S2, determining whether the difference between the latest message time of the standby link and the current system time is greater than two preset periods, if yes, the switching is not performed and the delay waiting period is cleared; if no, the next step is entered; Step S3, determining whether the current system time is in the delay waiting period, if yes, the primary link and the standby link are switched, a link switching alarm is triggered and the delay waiting period is cleared; if no, the delay waiting period is entered, and steps S1 to S3 are repeated; The delay waiting period is one period.

2. The dual network redundant transmission method based on link selection according to claim 1, wherein, The data sending node record comprises the IP address of the data sending node, the primary link, the latest message time of the primary link and the standby link; The IP address of the data sending node is used as an index; The time when the network card of the data receiving node first receives the message data from the data sending node is set as the latest message time of the primary link; the latest message time of the standby link is preset as 0.

3. The dual network redundant transmission method based on link selection according to claim 2, characterized in that, The determination whether the data sending node record exists comprises index searching whether the data sending node record exists; The updating of the data sending node record in the node link state table according to the message data comprises: Index searching the corresponding data sending node record according to the IP address of the data sending node; According to the time when the data receiving node receives the message data, the latest message time of the corresponding on-duty link or standby link of the network card is updated.

4. The dual network redundant transmission method based on link selection according to claim 2, characterized in that, According to the updated record of the data sending node, it is judged whether to send the message data, including: if the message data comes from the on-duty link, the message data is sent; if the message data comes from the standby link, the message data is discarded. The message data from the on-duty link is sent according to the record of the data sending node.

5. The dual network redundant transmission method based on link selection according to claim 4, characterized in that, The message time and system time are recorded by using the jiffies global variable of the operating system.

6. The dual network redundant transmission method based on link selection according to claim 2, characterized in that, The data receiving node obtains the network card fault information in real time, and judges whether to switch the on-duty link and standby link of the corresponding data sending node; the process is as follows: It is judged whether the data receiving node receives the network card fault information, if yes, the network card fault alarm is triggered; According to the fault information, the node link state table is traversed, it is judged whether the fault network card has a corresponding on-duty link, if yes, the corresponding data sending node of the on-duty link is obtained, and the on-duty link and standby link of the data sending node are switched and the link switching alarm is triggered.

7. A dual network redundant transmission apparatus based on link selection, characterized by, Two transmission networks and at least two double network card nodes are included, the two transmission networks are independent and parallel; the double network card node includes two network cards, the double network card node is connected to the two transmission networks through the two network cards; when the two double network card nodes are respectively used as data sending nodes and data receiving nodes, a double network redundancy transmission method based on link selection is used for message data transmission, as claimed in any one of claims 1-6. The two network cards corresponding to the data sending node have the same MAC address and IP address; the two network cards corresponding to the data receiving node have the same MAC address and IP address.

8. The dual network redundant transmission device based on link selection according to claim 7, characterized in that, The double network redundancy transmission device further includes a single network card node, the single network card node includes one network card, and the single network card node is connected to any transmission network through the network card. When the single network card node is used as a data sending node, the data sending node sends message data to the corresponding transmission network through the network card, the data receiving node receives the message data through the corresponding network card of the transmission network and sends it up, and the message data transmission is completed. When the single network card node is used as a data receiving node, the data receiving node receives the message data sent by the data sending node from the corresponding transmission network through the network card and sends it up, and the message data transmission is completed.

9. The dual network redundant transmission device based on link selection according to claim 8, characterized in that, When the single network card node is used as a data sending node, the data receiving node obtains the network card fault information in real time, and triggers the network card fault alarm based on the network card fault information.

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