Onboard FC message transmission method based on publishing and subscribing

Abstract

The invention provides an airborne FC message transmission method based on publishing and subscribing, and belongs to the technical field of aviation airborne computer network communication, and the method specifically comprises the steps: building a publishing table and a subscribing table based on a client and server model mode, enabling a terminal as a client to initiate a publishing request and a subscribing request to a server based on a network management message, and transmitting the publishing request and the subscribing request to the server; the switch serves as a server to process the publishing request and the subscription request and manage message reply response based on the network. The method comprises the steps of performing a message publishing process based on a publishing table, performing a message subscription process based on a subscription table, performing a message sending process based on the publishing table and performing a message receiving process based on the subscription table. Through the processing scheme provided by the invention, the maintenance cost is reduced, a flexible network platform is provided for the system, and a feasible scheme basis is provided for switching message planning during operation.

Description

Technical Field

[0001] The present application relates to the technical field of aviation airborne computer network communication, and in particular to an airborne FC message transmission method based on publish-subscribe. Background Art

[0002] Airborne FC message transmission relies on the configuration data pre-planned and defined by the system. The configuration data defines the network topology and message planning of the FC network. The network topology determines the connection relationship between the network terminal and the switch, and the message planning determines the correspondence between the message and the FC terminal. The computing device corresponding to each terminal contains several application function modules, and each application function module uses several messages to communicate across terminals. Through this correspondence, the message communication table of each terminal and the forwarding table of the switch can be determined. The message communication table of the terminal and the forwarding table of the switch are the configuration data of the FC network system.

[0003] The basis for the coordinated operation of the FC communication network is that the switches and terminals use unified configuration data, that is, the message communication table used by the terminal and the forwarding table used by the switch can correspond to each other. Figure 1 shown.

[0004] Before the system is running, the system planning (network topology and message planning) must be converted into configuration data used by the terminal and the switch and solidified in the non-volatile memory of the terminal and the switch. When the system starts, the terminal must read and parse the configuration data from the non-volatile memory, convert it into a sending communication table and a receiving communication table and temporarily store it in the memory for message communication. The sending communication table contains the message identifier and target port identifier of the FC message to be sent, and the receiving communication table contains the message identifier of the FC message to be received. The switch must also read and parse the configuration data from the non-volatile memory, convert it into a forwarding table and temporarily store it in the memory.

[0005] The FC message transmission system that relies on the pre-planned definition of configuration data is simple in design, easy to implement, and has strong stability and certainty. However, in the face of task systems that frequently change system plans, the FC message transmission system has the following shortcomings:

[0006] 1. System operation depends on pre-planned configuration data. Once system requirements change, such as adding or reducing communication messages or changing the source or destination terminals of messages, the configuration data needs to be regenerated and solidified in the non-volatile memory of all terminals and switches in the FC network. The change cost is high, the change cycle is long, and the impact range is large.

[0007] 2. For systems that require switching message planning during operation, the transmission system that uses pre-planned defined configuration data needs to store several configuration data in the non-volatile memory for system switching, which will greatly occupy the storage space of the terminal device, and the switching configuration data needs to be read from the peripheral device and run on the host side, which will affect the real-time performance of the switching message planning. Summary of the invention

[0008] In view of this, the embodiment of the present application provides an airborne FC message transmission method based on publish-subscribe, which provides another implementation method for airborne FC message transmission in addition to relying on system pre-planned configuration data, thereby solving the problems of high cost of system message planning change, high time resource occupation of switching message planning space during system operation in the prior art.

[0009] The embodiment of the present application provides an airborne FC message transmission method based on publish-subscribe, the method comprising:

[0010] A publishing table and a subscription table are established based on a client and server model. The terminal, as a client, initiates a publishing request and a subscription request to the server based on a network management message. The switch, as a server, processes the publishing request and the subscription request and replies based on the network management message, including: a message publishing process based on the publishing table, a message subscription process based on the subscription table, a message sending process based on the publishing table, and a message receiving process based on the subscription table.

[0011] According to a specific implementation method of the embodiment of the present application, the publishing table describes the published message identifier and the publishing destination Bitmap, and the subscription table describes the subscribed message identifier and the subscriber.

[0012] According to a specific implementation method of an embodiment of the present application, the publication table includes a global publication table and a local publication table, the local publication table is a subset of the global publication table, and one local publication table corresponds to one terminal; the global publication table is stored on the switch, and all published messages of terminals in the network are arranged in ascending order according to the terminal number in the global publication table. The global publication table is used for locating the publisher of a message when a message is subscribed, and notifying the publisher of the message about the location information of the new subscriber; the local publication tables are stored on the corresponding terminals respectively, and the local publication tables store the collection of messages published by the terminal itself to the outside.

[0013] According to a specific implementation method of an embodiment of the present application, the subscription table includes a global subscription table and a local subscription table, the local subscription table is a subset of the global subscription table, and one local subscription table corresponds to one terminal; the global subscription table is stored on the switch, and all subscribed messages of all terminals in the network are arranged in ascending order according to the terminal number in the global subscription table. The global subscription table is used for locating the subscriber set of a message when a message is published, and notifying the publisher of all location information about the subscriber set of the message; the local subscription table is stored on the terminal, and the local subscription table stores the set of the terminal's own subscription messages.

[0014] According to a specific implementation method of an embodiment of the present application, the publishing purpose Bitmap describes the location information of the message subscriber, which is implemented through a Bitmap data structure. A bitmap is used to represent each terminal on the network. When the value of a certain bit is 1, it indicates that the terminal corresponding to the bit has subscribed to the current message. When the value of a certain bit is 0, it indicates that the terminal corresponding to the bit has not subscribed to the current message.

[0015] According to a specific implementation method of an embodiment of the present application, the message identifier is described by an unsigned integer variable ranging from 0x0 to 0xFFFFFFFF. The message identifier in the network is globally unique. Each message can only be published by a single publisher and subscribed to by multiple subscribers.

[0016] According to a specific implementation of an embodiment of the present application, the message publishing process based on the publishing table includes:

[0017] Step 101: Terminal X starts publishing the request response process;

[0018] Step 102: Terminal X updates the local local publishing table, which contains the message set P{M1,M2,...,M i ,……,M N}, where M i is the message identification number, N is the number of messages published at a time, if M does not exist in the local publishing table i , then M i Insert into the local publication table sequentially; otherwise, skip the update; go to step 103;

[0019] Step 103: Terminal X sends a publishing request to the switch, the content of which is a message set P{M1,M2,...,M i ,……,M N}, go to step 104;

[0020] Step 104: Terminal X waits for the switch to respond. If the response is received successfully, go to step 105. If the waiting timeout occurs, the publishing process ends.

[0021] Step 105: The switch checks whether the publication table corresponding to terminal X in the global publication table already has M i . If not, the switch inserts M i sequentially into the publication table corresponding to terminal X and proceeds to step 106; if it exists, directly proceed to step 106;

[0022] Step 106: The switch sequentially searches the global subscription table for the set of terminals subscribing to the subscription message M i . If the set is not empty, proceed to step 107; otherwise, proceed to step 108;

[0023] Step 107: The switch forms a Bitmap from the set of terminals subscribing to the subscription message M i and updates the publication destination Bitmap in the global publication table according to the terminal set Bitmap;

[0024] Step 108: If i < N, then i = i + 1 and proceed to step 105; otherwise, proceed to step 109;

[0025] Step 109: The switch sends a publication update response to terminal X, notifying terminal X of the terminal set Bitmap corresponding to the publication message set P{M1, M2, ……, M i , ……, M N};

[0026] Step 1010: Terminal X updates the publication destination Bitmap in the local publication table according to the terminal set Bitmap;

[0027] Step 1011: The publication process ends.

[0028] According to a specific implementation manner of the embodiment of the present application, the message subscription process based on the subscription table includes:

[0029] Step 201: Terminal Y starts the subscription request response process;

[0030] Step 202: Terminal Y updates the local local subscription table with the content being the set of messages to be subscribed S{M1, M2, ……, M j , ……, M P}(where M j is the message identification number and P is the number of single subscription messages). If M j does not exist in the local subscription table, then insert M j sequentially into the local subscription table; otherwise, skip the update and proceed to step 203;

[0031] Step 203: Terminal Y sends a subscription request to the switch, with the content being the set of messages to be subscribed S{M1, M2, ……, M j, ……, M P}, go to step 204;

[0032] Step 204: The terminal Y waits to receive the switch reply. If the reply is successfully received, go to step 205; if the waiting times out, end the subscription process;

[0033] Step 205: The switch checks whether M already exists in the subscription table corresponding to the terminal Y in the global subscription table. If it does not exist, the switch inserts M j sequentially into the subscription table corresponding to the terminal Y, and go to step 206; if it exists, directly go to step 206; j

[0034] Step 206: The switch sequentially searches for the terminal A that publishes the message M in the global publication table. If the terminal exists, go to step 207; otherwise, go to step 2010; j

[0035] Step 207: The switch forms the location information of the terminal Y into a Bitmap and updates the publication destination Bitmap in the local publication table corresponding to the terminal A in the global publication table;

[0036] Step 208: The switch sends a subscription update response to the terminal A and notifies the terminal A of the terminal set Bitmap;

[0037] Step 209: The terminal A updates the publication destination Bitmap in the local publication table according to the terminal Bitmap;

[0038] Step 2010: If j < P, then j = j + 1, go to step 205; otherwise, go to step 2011;

[0039] Step 2011: The subscription process ends.

[0040] According to a specific implementation manner of the embodiment of the present application, the process of sending a message based on the publication table includes:

[0041] Step 301: The terminal X creates the data to be sent and determines the message identifier M to be sent i ;

[0042] Step 302: The terminal X queries the local local publication table to check whether M i exists; if it exists, go to step 303; otherwise, the sending fails and go to step 306;

[0043] Step 303: Query whether the publication destination Bitmap corresponding to M i in the local publication table is empty. If it is not empty, go to step 304; otherwise, the sending fails and go to step 306;

[0044] ​​Step 304: Traverse the corresponding publishing destination Bitmap from low to high, and combine the terminals corresponding to all the bits set to 1 into a terminal set {D1, D2, ..., D i ,……,D Q}, where D i is the device identification number, Q is the number of subscribed devices;

[0045] Step 305: Send the following signals to D1, D2, ..., D Q Send message M i ;

[0046] Step 306: The message sending process ends.

[0047] According to a specific implementation manner of an embodiment of the present application, the message receiving process based on the subscription table includes:

[0048] Step 401: Terminal Y receives message data on the FC link and parses the message identifier M j ;

[0049] Step 402: Terminal Y queries the local subscription table to see if M j ; If it exists, go to step 403; otherwise, discard the message and go to step 404;

[0050] Step 403: Terminal Y sends message M j Submit to data reader;

[0051] Step 404: The message receiving process ends.

[0052] Beneficial effects:

[0053] The airborne FC message transmission method based on publish-subscribe in the embodiment of the present application has the following advantages:

[0054] Low maintenance cost. When the system message plan changes, it only involves the application function modules of the relevant terminals, not the entire network terminals, which reduces the impact of the message plan change, reduces maintenance costs, and provides a flexible network platform for the system;

[0055] Low resource usage. When the system is running, the message plan can be switched freely through dynamic message publishing and subscription. Since it does not involve data access and storage between the host and the peripherals, it greatly reduces the space and time resource usage, providing a feasible solution for switching message plans at runtime. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0057] Figure 1 A schematic diagram of a message configuration in the prior art;

[0058] Figure 2 A schematic diagram of a publish-subscribe based airborne FC message transmission method according to an embodiment of the present invention;

[0059] Figure 3 A subscription representation diagram of an onboard FC message transmission method based on publish-subscribe according to an embodiment of the present invention;

[0060] Figure 4 A schematic diagram of a message publishing process of an airborne FC message transmission method based on publish-subscribe according to an embodiment of the present invention;

[0061] Figure 5 A schematic diagram of a message subscription process of an onboard FC message transmission method based on publish-subscribe according to an embodiment of the present invention;

[0062] Figure 6 A schematic diagram of a message sending process of an onboard FC message transmission method based on publish-subscribe according to an embodiment of the present invention;

[0063] Figure 7 Schematic diagram of a message receiving process of an onboard FC message transmission method based on publish-subscribe according to an embodiment of the present invention. DETAILED DESCRIPTION

[0064] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0065] The following describes the implementation methods of the present application through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0066] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0067] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0068] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0069] This application provides a feasible airborne FC message transmission method based on publish-subscribe, which provides another implementation method for airborne FC message transmission besides relying on system pre-planned configuration data. It has solved the problems of high cost of system message planning change, high space and time resource occupation of switching message planning during system operation in the prior art. Figures 2 to 7 The publish-subscribe based airborne FC message transmission method provided in an embodiment of the present application is described in detail.

[0070] In one embodiment, the publish-subscribe based airborne FC message transmission method comprises the following steps:

[0071] A publishing table and a subscription table are established based on a client and server model. The terminal, as a client, initiates a publishing request and a subscription request to the server based on a network management message. The switch, as a server, processes the publishing request and the subscription request and replies based on the network management message, including: a message publishing process based on the publishing table, a message subscription process based on the subscription table, a message sending process based on the publishing table, and a message receiving process based on the subscription table.

[0072] Specifically, the publication and subscription of FC messages may occur at any time. The FC network automatically completes the logical connection between the publisher and subscriber of each FC message, and this connection is established on the publish-subscribe relationship table. The publish-subscribe relationship is established based on the client / server model. The terminal, as a client, initiates a publish and subscribe request to the network server based on the network management message. The switch, as a network server, processes the request and replies based on the network management message.

[0073] The method of this embodiment has the following advantages: Low maintenance cost: When the system message plan changes, only the application function modules of the relevant terminals are involved, not the terminals in the entire network, which reduces the impact of the message plan change, reduces the maintenance cost, and provides a flexible network platform for the system. Low resource occupation: When the system is running, the message plan can be freely switched through dynamic message publishing and subscription. Since it does not involve data access and storage between the host and the peripherals, the occupation of space and time resources is greatly reduced, providing a feasible solution basis for switching message plans at runtime.

[0074] In one embodiment, the publishing table describes the published message identifier and the publishing destination Bitmap, and the subscription table describes the subscribed message identifier and the subscriber.

[0075] Specifically, refer to Figure 2 The publishing table includes a global publishing table and a local publishing table. The local publishing table is a subset of the global publishing table. One local publishing table corresponds to one terminal. The global publishing table is stored on the switch. All the published messages of the terminals in the network are arranged in ascending order according to the terminal number in the global publishing table. Figure 2 Each terminal in the system corresponds to a publishing table of the terminal, and the tables are arranged in ascending order according to the terminal number. The global publishing table is used for locating the publisher of the message when a message is subscribed, and notifying the publisher of the message of the new subscriber location information; the local publishing tables are respectively stored on the corresponding terminals, and the local publishing tables store the collection of messages published by the terminal itself, such as Figure 2 Each local publishing table contains multiple publishing tables of the terminal, and each publishing table of the terminal contains information of message ID (message identification), publishing destination Bitmap and message description.

[0076] The global publishing table and local publishing table are created in the host memory after the switch and terminal are powered on, and disappear after power off. The host memory is initially empty and is updated by the publish-subscribe process.

[0077] Further, see Figure 3The subscription table includes a global subscription table and a local subscription table. The local subscription table is a subset of the global subscription table. One local subscription table corresponds to one terminal. The global subscription table is stored on the switch. All subscribed messages of the terminals in the network are arranged in ascending order according to the terminal number in the global subscription table. Figure 3 Each terminal in the system corresponds to a subscription table of the terminal, and the subscription tables are arranged in ascending order according to the terminal number. The global subscription table is used for locating the subscriber set of the message when a message is published, and notifying the publisher of all the location information of the subscriber set of the message; the local subscription table is stored on the terminal, and the local subscription table stores the set of the terminal's own subscription messages, such as Figure 3 Each local subscription table includes multiple subscription tables of the terminal, and each subscription table of the terminal includes information of a message ID (message identification) and a message description.

[0078] The global subscription table and local subscription table are created in the host memory after the switch and terminal are powered on, and disappear after power off. The host memory is initially empty and is updated by the publish-subscribe process.

[0079] In specific implementation, the interaction process of the client / server model includes: the terminal initiates a publishing request to the network server, the switch processes the request as a server, and replies to the terminal with the destination Bitmap corresponding to the published message set as a publishing update response, and updates the terminal's local publishing table. The terminal initiates a subscription request to the network server, the switch processes the request as a server, adds the terminal that initiates the subscription to the global subscription table, and replies to the message publisher with the destination Bitmap corresponding to the subscription message as a subscription update response, and updates the terminal's local publishing table.

[0080] In one embodiment, the publishing destination Bitmap describes the location information of the message subscriber, which is implemented through a Bitmap data structure, and uses a bitmap to represent each terminal on the network, for example, bit0 to bit31 represent terminal 1 to terminal 32. When the value of a certain bit is 1, it means that the terminal corresponding to the bit has subscribed to the current message, and when the value of a certain bit is 0, it means that the terminal corresponding to the bit has not subscribed to the current message.

[0081] Furthermore, the message identifier is described by an unsigned integer variable ranging from 0x0 to 0xFFFFFFFF. The message identifier in the network is globally unique. Each message can only be published by a single publisher and subscribed to by multiple subscribers.

[0082] In specific implementation, this application implements message subscription and publishing based on the designed publishing table and subscription table. Any FC message published by the publisher is recorded by the client in its local publishing table, and the server is notified to refresh the global publishing table. When a message is subscribed to by one or more subscribers, the server establishes a publish-subscribe relationship table and notifies the publisher of the message to add the relevant subscribers to the subscriber list of the message. Any FC message subscribed by the subscriber is recorded by the client in its local subscription table, and the server is notified to refresh the global subscription table. If the server detects that the newly subscribed message already has a corresponding publisher, the server notifies the publisher to add the new subscriber to the subscriber list.

[0083] Simply put, the FC message transmission system includes the publisher's message sending process and the subscriber's message receiving process.

[0084] The basic process of a publisher sending a message is as follows:

[0085] 1. The publisher creates the data to be sent and determines the message identifier;

[0086] 2. The publisher checks whether the message ID exists in the local publishing table;

[0087] 3. The publisher checks whether there is a subscriber for the message;

[0088] 4. Transmit the message to all subscribers.

[0089] The basic process of receiving messages by subscribers is as follows:

[0090] 1. Subscribers receive data;

[0091] 2. The subscriber checks whether the message ID exists in the local subscription table;

[0092] 3. Submit messages to upper-layer applications.

[0093] The following is a detailed description of the message publishing process, message subscription process, message sending process and message receiving process.

[0094] In one embodiment, referring to Figure 4 The message publishing process based on the publishing table includes:

[0095] Step 101: Terminal X starts publishing the request response process;

[0096] Step 102: Terminal X updates the local local publishing table, which contains the message set P{M1,M2,...,M i ,……,M N}, where M i is the message identification number, N is the number of messages published at a time, if M does not exist in the local publishing tablei , then insert M i sequentially into the local publication table; otherwise, skip the update; go to step 103;

[0097] Step 103: Terminal X sends a publication request to the switch, with the content being the set of messages to be published P{M1, M2, ……, M i , ……, M N} and go to step 104;

[0098] Step 104: Terminal X waits to receive the switch's response. If the response is received successfully, go to step 105; if the waiting times out, end the publication process;

[0099] Step 105: The switch checks the publication table corresponding to Terminal X in the global publication table to see if M i already exists. If it does not exist, the switch inserts M i sequentially into the publication table corresponding to Terminal X and go to step 106; if it exists, directly go to step 106;

[0100] Step 106: The switch sequentially searches in the global subscription table for the set of terminals subscribing to the subscription message M i . If the set is not empty, go to step 107; otherwise, go to step 108;

[0101] Step 107: The switch forms a Bitmap from the set of terminals subscribing to the subscription message M i and updates the publication destination Bitmap in the global publication table according to the terminal set Bitmap;

[0102] Step 108: If i < N, then i = i + 1 and go to step 105; otherwise, go to step 109;

[0103] Step 109: The switch sends a publication update response to Terminal X, notifying Terminal X of the terminal set Bitmap corresponding to the set of publication messages P{M1, M2, ……, M i , ……, M N};

[0104] Step 1010: Terminal X updates the publication destination Bitmap in the local publication table according to the terminal set Bitmap;

[0105] Step 1011: The publication process ends.

[0106] Furthermore, referring to Figure 5 , the message subscription process based on the subscription table includes:

[0107] Step 201: Terminal Y starts the subscription request response process;

[0108] Step 202: The terminal Y updates the local partial subscription table, and the content is the set S{M1, M2, ……, M j , ……, M P}(where M j is the message identification number, and P is the number of messages subscribed at one time). If M j does not exist in the local subscription table, then insert M j into the local subscription table in sequence; otherwise, skip the update; go to Step 203;

[0109] Step 203: The terminal Y sends a subscription request to the switch, and the content is the set S{M1, M2, ……, M j , ……, M P}, and go to Step 204;

[0110] Step 204: The terminal Y waits to receive the switch response. If it is successfully received, go to Step 205; if the waiting times out, end the subscription process;

[0111] Step 205: The switch checks the subscription table corresponding to the terminal Y in the global subscription table to see if M j already exists. If it does not exist, the switch inserts M j into the subscription table corresponding to the terminal Y in sequence, and go to Step 206. If it exists, directly go to Step 206;

[0112] Step 206: The switch sequentially searches for the terminal A that publishes the message M j in the global publication table. If the terminal exists, go to Step 207; otherwise, go to Step 2010;

[0113] Step 207: The switch forms the location information of the terminal Y into a Bitmap and updates the publication destination Bitmap in the local publication table corresponding to the terminal A in the global publication table;

[0114] Step 208: The switch sends a subscription update response to the terminal A and notifies the terminal A of the terminal set Bitmap;

[0115] Step 209: The terminal A updates the publication destination Bitmap in the local publication table according to the terminal Bitmap;

[0116] Step 2010: If j < P, then j = j + 1, and go to Step 205; otherwise, go to Step 2011;

[0117] Step 2011: The subscription process ends.

[0118] Furthermore, referring to Figure 6 , the process of sending messages based on the publication table includes:

[0119] Step 301: Terminal X creates data to be sent and determines the message identifier M to be sent i ;

[0120] Step 302: Terminal X queries the local local publication table to see if M i ; If it exists, go to step 303; otherwise, the sending fails, go to step 306;

[0121] Step 303: Query the local publication table M i Whether the corresponding publishing destination Bitmap is empty, if not, go to step 304; otherwise, the sending fails, go to step 306;

[0122] Step 304: Traverse the corresponding publishing destination Bitmap from low to high, and combine the terminals corresponding to all the bits set to 1 into a terminal set {D1, D2, ..., D i ,……,D Q}, where D i is the device identification number, Q is the number of subscribed devices;

[0123] Step 305: Send the following signals to D1, D2, ..., D Q Send message M i ;

[0124] Step 306: The message sending process ends.

[0125] Further, see Figure 7 , the message receiving process based on the subscription table includes:

[0126] Step 401: Terminal Y receives message data on the FC link and parses the message identifier M j ;

[0127] Step 402: Terminal Y queries the local subscription table to see if M j ; If it exists, go to step 403; otherwise, discard the message and go to step 404;

[0128] Step 403: Terminal Y sends message M j Submit to data reader;

[0129] Step 404: The message receiving process ends.

[0130] In the embodiment provided by the present invention, based on the client / server model, the terminal initiates a message publishing and subscription process to the switch, and establishes a terminal local publishing and subscription table and a switch global publishing and subscription table. The switch initiates a publishing and subscription update response process to the terminal, and updates the terminal local publishing and subscription table. Thus, message transmission between terminals based on the local publishing and subscription table is realized.

[0131] The present invention aims at adopting the scheme of pre-planning and defining configuration data for message transmission by the system, solves the problems of high cost of message planning change, high space and time resource occupation of switching message planning during system operation, reduces maintenance cost, provides a flexible network platform for the system, and provides a feasible solution basis for switching message planning at runtime.

[0132] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A publish-subscribe based airborne FC message transmission method, characterized in that: The method includes: Establishing a publication table and a subscription table based on the client - server model. The terminal, as the client,发起 a publication request and a subscription request to the server based on network management messages. The switch, as the server, processes the publication request and the subscription request and回复 a response based on network management messages, including: a message publication process based on the publication table, a message subscription process based on the subscription table, a message sending process based on the publication table, and a message receiving process based on the subscription table.

2. The airborne FC message transmission method based on publish-subscribe according to claim 1, characterized in that: The publication table describes the published message identifier and the publication - purpose Bitmap. The subscription table describes the subscribed message identifier and the subscriber.

3. The publish-subscribe based airborne FC message transmission method according to claim 2, characterized in that: The publication table includes a global publication table and a local publication table. The local publication table is a subset of the global publication table, and one local publication table corresponds to one terminal. The global publication table is stored on the switch. All the messages published by terminals in the network are arranged in ascending order of terminal numbers in the global publication table. The global publication table is used to locate the publisher of a message when the message is subscribed and notify the publisher of the location information of the new subscribers. The local publication tables are respectively stored on the corresponding terminals, and the local publication table stores the set of messages published by the terminal itself.

4. The publish-subscribe based airborne FC message transmission method according to claim 3, characterized in that: The subscription table includes a global subscription table and a local subscription table. The local subscription table is a subset of the global subscription table, and one local subscription table corresponds to one terminal. The global subscription table is stored on the switch. All the messages subscribed by terminals in the network are arranged in ascending order of terminal numbers in the global subscription table. The global subscription table is used to locate the set of subscribers of a message when the message is published and notify the publisher of all the location information of the set of subscribers of the message. The local subscription table is stored on the terminal, and the local subscription table stores the set of messages subscribed by the terminal itself.

5. The publish-subscribe based airborne FC message transmission method according to claim 3, characterized in that: The publication - purpose Bitmap describes the location information of message subscribers, which is implemented through the Bitmap data structure. Each terminal on the network is represented by a bit. When the value of a certain bit is 1, it means that the terminal corresponding to this bit has subscribed to the current message. When the value of a certain bit is 0, it means that the terminal corresponding to this bit has not subscribed to the current message.

6. The publish-subscribe based airborne FC message transmission method according to claim 4, characterized in that: The message identifier is described by an unsigned integer variable, ranging from 0x0 to 0xFFFFFFFF. The message identifiers in the network are globally unique. Each message can only be published by a single publisher and can be subscribed by multiple subscribers.

7. The publish-subscribe based airborne FC message transmission method according to claim 4, characterized in that: The message publication process based on the publication table includes: Step 101: Terminal X starts the publication - request response process; Step 102: Terminal X updates the local local publishing table, which contains the message set P{M1,M2,...,M i ,……,M N }, where M i is the message identification number, N is the number of messages published at a time, if M does not exist in the local publishing table i , then M i Insert into the local publication table sequentially; otherwise, skip the update; go to step 103; Step 103: Terminal X sends a publishing request to the switch, the content of which is a message set P{M1,M2,...,M i ,……,M N }, go to step 104; Step 104: Terminal X waits to receive the switch response. If successfully received, go to Step 105; if the waiting times out, end the publication process; Step 105: The switch checks whether the publishing table corresponding to terminal X in the global publishing table already exists. i If it does not exist, the switch will M i Sequentially insert it into the publishing table corresponding to terminal X, and go to step 106; if it exists, go directly to step 106; Step 106: The switch sequentially searches for the subscription message M in the global subscription table i If the terminal set is not empty, go to step 107; otherwise, go to step 108; Step 107: The switch subscribes to the message M i The terminal set is composed of a Bitmap, and the publishing destination Bitmap in the global publishing table is updated according to the terminal set Bitmap; Step 108: If i < N, then i = i + 1, go to Step 105; otherwise, go to Step 109; Step 109: The switch sends a publish update response to terminal X, publishing the message set P{M1,M2,...,M i ,……,M N }The corresponding terminal set Bitmap notifies terminal X; Step 1010: Terminal X updates the publication - purpose Bitmap in the local publication table according to the terminal - set Bitmap; Step 1011: The publication process ends.

8. The publish-subscribe based airborne FC message transmission method according to claim 7, characterized in that: The message subscription process based on the subscription table includes: Step 201: The terminal Y starts the subscription request response process; Step 202: Terminal Y updates the local subscription table, which contains the message set S {M1, M2, ..., M j ,……,M P }, where M j is the message identification number, P is the number of single subscription messages, if M does not exist in the local subscription table j , then M j Insert into the local subscription table sequentially; otherwise, skip the update; go to step 203; Step 203: Terminal Y sends a subscription request to the switch, the content of which is the message set S{M1,M2,...,M j ,……,M P }, go to step 204; Step 204: The terminal Y waits to receive the switch response. If the reception is successful, go to Step 205; if the waiting times out, end the subscription process; Step 205: The switch checks whether the subscription table corresponding to terminal Y in the global subscription table already exists. j If it does not exist, the switch will M j Sequentially insert into the subscription table corresponding to terminal Y, and go to step 206. If it exists, go directly to step 206; Step 206: The switch searches the global publication table for the published message M in sequence j If the terminal exists, go to step 207; otherwise, go to step 2010; Step 207: The switch forms a Bitmap of the location information of the terminal Y and updates the published destination Bitmap in the local publication table corresponding to the terminal A in the global publication table; Step 208: The switch sends a subscription update response to the terminal A and notifies the terminal A of the terminal set Bitmap; Step 209: The terminal A updates the published destination Bitmap in the local publication table according to the terminal Bitmap; Step 2010: If j < P, then j = j + 1, go to Step 205; otherwise, go to Step 2011; Step 2011: The subscription process ends.

9. The publish-subscribe based airborne FC message transmission method according to claim 8, characterized in that: The message sending process based on the publication table includes: Step 301: Terminal X creates data to be sent and determines the message identifier M to be sent. i ; Step 302: Terminal X queries the local local publication table to see if M i ; If it exists, go to step 303; otherwise, the sending fails, go to step 306; Step 303: Query the local publication table M i Whether the corresponding publishing destination Bitmap is empty, if not, go to step 304; otherwise, the sending fails, go to step 306; Step 304: Traverse the corresponding publishing destination Bitmap from low to high, and combine the terminals corresponding to all the bits set to 1 into a terminal set {D1, D2, ..., D i ,……,D Q }, where D i is the device identification number, Q is the number of subscribed devices; Step 305: Send the following signals to D1, D2, ..., D Q Send message M i ; Step 306: The message sending process ends.

10. The publish-subscribe based airborne FC message transmission method according to claim 9, characterized in that: The message receiving process based on the subscription table includes: Step 401: Terminal Y receives message data on the FC link and parses the message identifier M j ; Step 402: Terminal Y queries the local subscription table to see if M j ; If it exists, go to step 403; otherwise, discard the message and go to step 404; Step 403: Terminal Y sends message M j Submit to data reader; Step 404: The message receiving process ends.

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