Service Scheduling Method Based on Time-Triggered Ethernet

Abstract

The present invention discloses a service scheduling method based on time-triggered Ethernet, which calculates the number of end systems and switches according to service flow parameters, determines the topology structure, establishes a port connection matrix, plans the shortest path, allocates services in each matrix period, sorts services in each basic period, establishes an overall schedule in one matrix period, and generates a service schedule for each end node and switch. The present invention realizes the scheduling of TT services, which allows each end node and switch to transmit TT tasks in order without contention, while saving network bandwidth and improving the utilization rate of network links.

Description

[Technical field]

[0001] The present invention belongs to the technical field of computer network communication, and particularly relates to a service scheduling method based on time-triggered Ethernet. [Background technology]

[0002] With the development of the aerospace industry, the demand for avionics systems is increasing, including high bandwidth, high reliability, low latency and high fault tolerance. After a long period of research and development, TTE (Time Trigger Ethernet) has emerged. This technology adds time synchronization technology and time trigger technology to Ethernet, which can not only handle time-triggered services (TT) with very high real-time requirements, but also handle rate-limited services (RC) and ordinary Ethernet services (BE), that is, it can simultaneously meet the needs of real-time and non-real-time applications.

[0003] Among all services, the TT service has the strictest time certainty requirements and has the highest priority. The transmission of the TT service is based on the global clock, and the service transmission and reception must be performed at a predetermined period in strict accordance with the time schedule, thereby ensuring its requirements of high real-timeness and low delay jitter, and avoiding data frames competing with each other for the limited physical links in the network. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of this, the present invention aims to provide a service scheduling method based on time-triggered Ethernet, which can realize the transmission and reception control of TT services. [Means for solving the problem]

[0005] A service scheduling method based on time-triggered Ethernet, comprising: Step 1: Obtaining parameters for all time-triggered services to be sent and received; Step 2, which calculates the number of end nodes ES and switches SW required based on the services to be transmitted and received, to obtain a minimum system; Step 3 of establishing a topology structure of the system based on the minimum system determined in step 2, in which the end nodes ES and the switches SW are both called connection nodes of the system, and an ordering is performed on the connection nodes; Step 4: based on the topology structure of the system established in step 3, establishing a connection relationship matrix between the connection nodes, including a connection matrix between the connection ports of the switch SW and other switches SW or end nodes ES; Step 5, based on the topology structure and the connection matrix of the connecting nodes in steps 3 and 4, the distance between two directly connected nodes is set to 1, the connection distance of the same node is set to 0, and the distance between nodes that are not directly connected is set to infinity, represented by X, and calculate the shortest transmission path between any two nodes, including the total distance of the shortest transmission path and the number of the intermediate connecting node; Step 6 to obtain network parameters; Step 7 of calculating a basic period BC and a matrix period MC according to the service flow parameters in step 1, where the matrix period MC includes multiple basic periods BC and is used for transmitting each of all services once; Step 8: assigning each service to each basic period BC in one matrix period MC according to the period of the service, and establishing a service assignment table in one matrix period MC; Step 9: grouping all services allocated in each basic cycle BC according to different generation times of the services, sorting the services in each group based on priority, traversing each basic cycle BC in one matrix cycle MC, and completing sorting of the services according to priority; Step 10: for a service in one matrix cycle MC, a transmission / reception path is determined using the shortest transmission path in step 5 based on the source number and destination number of the service, and a transmission / reception time is determined based on the priority of the service and the transmission / reception path, and finally a whole schedule is formed in one matrix cycle MC; Step 11: identifying each access node according to the overall schedule of step 10, obtaining a transmission / reception schedule of each access node, and generating a schedule file; and step 12 of scheduling transmission and reception for the service based on the schedule file of step 11.

[0006] Preferably, in step 8, after each service is assigned to each basic cycle BC, services having the same cycle are assigned to different basic cycles with a shift, to obtain a service assignment table.

[0007] Preferably, in step 5, the specific method for establishing one final shortest transmission path table is as follows: Arrange all the connection node numbers in row and column order, The first intermediate node z between the connecting node x and the connecting node y is located at the xth row and yth column, the second intermediate node t is located at the zth row and yth column, and the second intermediate node t is located at the tth row and yth column, and then the last intermediate node is located at the tth row and yth column. Then, the two connecting nodes are traversed to obtain a shortest transmission path table.

[0008] Preferably, each switch SW includes four full-duplex ports.

[0009] Preferably, the two switches SW are directly connected, and the two end systems ES should be connected via a switch SW.

[0010] Preferably, the parameters of the time-triggered service include an ID number, a frame length, a period, a source system number, a destination system number and a service generation time point of each service. Effect of the Invention

[0011] The present invention has the following beneficial effects:

[0012] The present invention discloses a service scheduling method based on time-triggered Ethernet, which calculates the number of end systems and switches according to service flow parameters, determines the topology structure, establishes a port connection matrix, plans the shortest path, allocates services in each matrix period, sorts services in each basic period, establishes an overall schedule in one matrix period, and generates a service schedule for each end node and switch. The present invention realizes the scheduling of TT services, so that each end node and switch can transmit TT tasks in order without contention, while saving network bandwidth and improving the utilization rate of network links. [Brief description of the drawings]

[0013] [Figure 1] 1 is a flow chart of an implementation of the present invention. [Diagram 2] FIG. 2 is a network topology diagram in a specific embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will now be described in detail with reference to the accompanying drawings.

[0015] 1. Obtain service flow parameters. Obtain all time-triggered (TT) services to be transmitted and received. The ID number, frame length, period, source system number, destination system number, and service generation time of each service are shown in Table 1.

[0016] Table 1 Service flow parameters [Table 1]

[0017] 2. Calculate the number of required end systems ES and switches SW, where each switch SW includes four full-duplex ports, and two switches SW may be directly connected, or two end systems ES need to be connected via a switch SW.

[0018] If the number of end systems involved in a service flow is 8, the number of required ESs in the system is at least 8, and the number of required SWs is at least m=8 / 2-1=5, i.e., we obtain a minimum system containing 8 end nodes and 5 switches.

[0019] 3. Based on the minimum system determined in step 2, establish a topology structure, as shown in Figure 2, in which the end systems ES and switches SW are both called connection nodes of the system, and rank the connection nodes, with numbers 1-8 representing end nodes ES1-ES8, and numbers 9-13 corresponding to switches SW1-SW5.

[0020] 4. Establish the port connection matrix. Based on the topology structure in step 3, the port matrix is ​​established, as shown in Table 2.

[0021] Table 2. Port Connection Table [Table 2]

[0022] The matrix has three columns, the first and second columns represent the connection nodes, and the third column represents the SW port numbers connected to the two connection nodes. For example, in the first row, the two connection nodes connected to each other are 9 and 10, and the port number is 1, which represents that node 9 is connected to node 10 through its port 1.

[0023] 5. Plan the shortest path. Based on the topology structure and node connection matrix in steps 3 and 4, establish a distance matrix. For any two nodes, the distance between two directly connected nodes is set to 1, the connection distance of the same node is 0, and the distance between nodes that are not directly connected is set to infinity, represented by X, as shown in Table 3.

[0024] Table 3 Connection distance table [Table 3]

[0025] The first column of the first row indicates that the distance between node 1 and itself is 0, the second column of the first row indicates that the distance between node 1 and node 2 is infinity, i.e., there is no direct connection, and the tenth column of the first row indicates that the distance between node 1 and node 10 is 1.

[0026] Based on the distance matrix, the shortest transmission path between any two nodes is calculated, including the total distance and the intermediate node numbers, as shown in Tables 4 and 5, respectively.

[0027] Table 4 Transmission distance table [Table 4]

[0028] For example, the 1st row, 7th column indicates that the total transmission distance from node 1 to node 7 is 3.

[0029] Table 5. Shortest transmission route table [Table 5]

[0030] For example, when inquiring about a transmission path from node 1 to node 7, first, the 7th column of the 1st row is confirmed as 10, which indicates transmission from node 1 to node 10 in step 1, then the 7th column of the 10th row is confirmed as 11, which indicates transmission from node 10 to node 11 in step 2, then the 7th column of the 11th row is confirmed as 7, which indicates transmission from node 11 to node 7 in step 3. That is, transmission from node 1 to node 7 is realized in three steps.

[0031] 6. Obtain network parameters, including link bandwidth (100Mbps), synchronization accuracy (200ns), delay between end system and switch (100ns), delay of end node itself (20ns), delay of switch itself (20ns), etc.

[0032] 7. Calculate the basic cycle BC and the matrix cycle MC. Based on the service flow parameters in step 1, calculate the basic cycle BC and the matrix cycle MC. The matrix cycle MC includes multiple basic cycles BC, and each of all services is transmitted once. The basic cycle BC is set to the greatest common divisor of each service cycle MC, 1 ms, and the matrix cycle MC is set to the least common multiple of each service cycle, 12 ms.

[0033] 8, Establish a TT service allocation table in one matrix period MC. According to the situation of TT services, TT services are allocated in each basic period BC in one matrix period MC, and then the basic period BC shift process is performed for TT services in the same period to obtain an optimized allocation means and avoid the contention of TT services, as shown in Table 6.

[0034] Table 6 TT service allocation table for one matrix cycle MC [Table 6]

[0035] 9. Process the allocation table in each BC. Process the TT services allocated in each basic period, group them according to the different generation times of the TT services, and perform priority processing for the services in each group based on the sending and receiving volume of the port. First, process the first BC. The results before processing are shown in Table 7, and the results after processing are shown in Table 8.

[0036] Table 7 Before treatment [Table 7]

[0037] Table 8 After processing [Table 8]

[0038] 10, establish an overall schedule in one matrix cycle MC. The same process is performed for each basic cycle BC in step 9 until the service processing of all basic cycles BC in one matrix cycle MC is completed. Then, time scheduling is performed for the TT services processed in one matrix cycle MC, and the transmission and reception paths are determined using the shortest transmission path table based on the source number and destination number of the service, and the transmission and reception times are determined based on the priority of the service and the transmission and reception paths, and finally an overall schedule in one matrix cycle MC is formed.

[0039] The first column is the ID number, the second column is the basic period number, the third to sixth columns represent transmission from the source node, with the source node number, transmission start time, transmission end time, and window length, respectively, followed by reception from the intermediate node and transmission from the intermediate node, with four columns forming one group, each representing the intermediate node number, reception / transmission start time, reception / transmission completion time, and window length, respectively, and the last four columns represent reception from the destination node, with the destination node number, reception start node, reception completion node, and window length, respectively.

[0040] 11. Generate a schedule for each node: Identify each node based on the overall schedule in step 10, obtain the sending and receiving schedule for each node, and generate a schedule file.

[0041] The sending table of source system 1, the receiving table of switch 2, the sending table of switch 3, and the receiving table of destination system 4 are shown in Tables 9-12, respectively.

[0042] Table 9. Source System 1 Transmission Table [Table 9-1] [Table 9-2]

[0043] Table 10. Switch 2 receive table [Table 10-1] [Table 10-2]

[0044] Table 11. Switch 3 transmit table [Table 11-1] [Table 11-2]

[0045] Table 12 Receiving table of destination system 4 [Table 12]

[0046] As described above, the preferred embodiments of the present invention are described, but are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0047] (Additional Note) (Appendix 1) Step 1: Obtaining parameters for all time-triggered services to be sent and received; Step 2, which calculates the number of end nodes ES and switches SW required based on the services to be transmitted and received, to obtain a minimum system; Step 3 of establishing a topology structure of the system based on the minimum system determined in step 2, in which the end nodes ES and the switches SW are both called connection nodes of the system, and an ordering is performed on the connection nodes; Step 4: based on the topology structure of the system established in step 3, establishing a connection relationship matrix between the connection nodes, including a connection matrix between the connection ports of the switch SW and other switches SW or end nodes ES; Step 5, based on the topology structure and the connection matrix of the connecting nodes in steps 3 and 4, the distance between two directly connected nodes is set to 1, the connection distance of the same node is set to 0, and the distance between nodes that are not directly connected is set to infinity, represented by X, and calculate the shortest transmission path between any two nodes, including the total distance of the shortest transmission path and the number of the intermediate connecting node; Step 6 to obtain network parameters; Step 7 of calculating a basic period BC and a matrix period MC according to the service flow parameters in step 1, where the matrix period MC includes multiple basic periods BC and is used for transmitting each of all services once; Step 8: assigning each service to each basic period BC in one matrix period MC according to the period of the service, and establishing a service assignment table in one matrix period MC; Step 9: grouping all services allocated in each basic cycle BC according to different generation times of the services, sorting the services in each group based on priority, traversing each basic cycle BC in one matrix cycle MC, and completing sorting of the services according to priority; Step 10: for a service in one matrix cycle MC, a transmission / reception route is determined using the shortest transmission route in step 5 based on the source number and destination number of the service, and a transmission / reception time is determined based on the priority of the service and the transmission / reception route, and finally a whole schedule is formed in one matrix cycle MC; Step 11: identifying each access node according to the overall schedule of step 10, obtaining a transmission / reception schedule of each access node, and generating a schedule file; Step 12: performing transmission and reception scheduling for the service based on the schedule file of step 11.

[0048] (Appendix 2) The service scheduling method based on time-triggered Ethernet described in Appendix 1, characterized in that in step 8, after each service is assigned to each basic period BC, services with the same period are assigned to different basic periods with a shift, thereby obtaining a service assignment table.

[0049] (Appendix 3) In the above step 5, the specific method of finally establishing one shortest transmission path table is as follows: Arrange all the connection node numbers in row and column order, The method for scheduling a service based on time-triggered Ethernet as described in Appendix 1, characterized in that the first intermediate node z between the connecting node x and the connecting node y is located at the xth row, yth column, the second intermediate node t is located at the zth row, yth column, and the tth row, yth column, and so on until the last intermediate node, traversing the two connecting nodes to obtain a shortest transmission path table.

[0050] (Appendix 4) The method for service scheduling based on time-triggered Ethernet as described in Supplementary Note 1, characterized in that each switch SW includes four full-duplex ports.

[0051] (Appendix 5) The service scheduling method based on time-triggered Ethernet as described in Supplementary Note 1, characterized in that two switches SW are directly connected and two end systems ES need to be connected via a switch SW.

[0052] (Appendix 6) The service scheduling method based on time-triggered Ethernet described in Appendix 1, characterized in that the parameters of the time-triggered service include the ID number, frame length, period, source system number, destination system number and service generation time of each service.

Claims

1. Step 1: acquiring parameters of all time-triggered services to be transmitted and received; Step 2 of calculating the number of required end nodes ES and switches SW based on the services to be transmitted and received, and obtaining a minimum system; Step 3 of establishing a topology structure of the system based on the minimum system determined in step 2, in which both the end nodes ES and the switches SW are called connection nodes of the system, and an ordering is performed on the connection nodes; Step 4: based on the topology structure of the system established in step 3, establishing a connection relationship matrix between connection nodes including a connection matrix between the connection ports of the switch SW and other switches SW or end nodes ES; Step 5, based on the topology structure and the connection matrix of the connection nodes in steps 3 and 4, set the distance between two directly connected nodes to 1, set the connection distance of the same node to 0, and set the distance between nodes that are not directly connected to infinity, represented by X, and calculate the shortest transmission path between any two nodes, including the total distance of the shortest transmission path and the number of the intermediate connection node; A step 6 of obtaining network parameters; Step 7 of calculating a basic period BC and a matrix period MC according to the service flow parameters in step 1, where the matrix period MC includes a plurality of basic periods BC, each of which is used for transmitting every service once; Step 8: assigning each service to each basic period BC in one matrix period MC according to the period of the service, and establishing a service assignment table in one matrix period MC; Step 9: grouping all the services allocated in each basic period BC according to different generation times of the services, sorting the services in each group based on priority, traversing each basic period BC in one matrix period MC, and completing sorting the services according to priority; Step 10: for a service in one matrix cycle MC, a transmission / reception route is determined using the shortest transmission route in step 5 based on the source number and destination number of the service, and a transmission / reception time is determined based on the priority of the service and the transmission / reception route, and finally a whole schedule is formed in one matrix cycle MC; Step 11: identifying each connection node based on the overall schedule of step 10, obtaining a transmission / reception schedule of each connection node, and generating a schedule file; Step 12 of scheduling transmission and reception for the service based on the schedule file of step 11; In the step 5, the specific method for finally establishing one shortest transmission path table is as follows: Arrange all the connection node numbers in row and column order, A service scheduling method based on time-triggered Ethernet, characterized in that a first intermediate node z between connection node x and connection node y is located at the xth row, yth column, a second intermediate node t is located at the zth row, yth column, and a second intermediate node t is located at the tth row, yth column, and so on until the last intermediate node is located, traversing the two connection nodes to obtain a shortest transmission path table.

2. 2. The method for scheduling services based on time-triggered Ethernet according to claim 1, wherein in step 8, after each service is assigned to each basic period BC, services with the same period are assigned to different basic periods with a shift, to obtain a service assignment table.

3. The method for time-triggered Ethernet-based service scheduling as claimed in claim 1, wherein each switch SW includes four full-duplex ports.

4. The method for service scheduling based on time-triggered Ethernet according to claim 1, characterized in that two switches SW need to be directly connected, and two end systems ES need to be connected via a switch SW.

5. 2. The method of claim 1, wherein the parameters of the time-triggered service include an ID number, a frame length, a period, a source system number, a destination system number and a service generation time point of each service.

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