Method and system for testing time delay and jitter of ring-type time-triggered Ethernet

Abstract

The invention relates to a time delay and jitter test method for a ring-type time-triggered Ethernet, and the method comprises the steps: S1, constructing a ring-type TTE network test architecture which comprises a ring topology formed by at least three switches, and at least two end systems which are respectively connected to different switch ports; s2, sending a test frame to an end system b through the end system a, and recording sending time t1 and receiving time t2; the end system b returns the test frame to the end system a, and the sending time t3 and the receiving time t4 are recorded; s3, calculating the transmission delay from the end system a to the end system b according to a transmission delay calculation formula delay = [(t2-t1) + (t4-t3)] / 2; and S4, repeatedly executing the steps S1 to S3 for multiple tests, and counting the difference value between the maximum value and the minimum value of the time delay as transmission jitter. According to the invention, the problem of time difference between systems is solved, and the time delay of CT frame sending between two end systems in one system can be accurately tested.

Description

Technical Field

[0001] The present invention relates to the field of Ethernet delay and jitter testing, and in particular to a method and system for testing the delay and jitter of a ring-type time-triggered Ethernet. Background Art

[0002] With the advent of a new era of communications, users can easily share data through Ethernet, making traditional Ethernet networks an indispensable element in people's lives. However, for networks with high requirements for real-time and reliable service transmission, it is necessary to ensure the stable transmission of important data within the network system. Traditional Ethernet data transmission is based on best-effort technology and is not protected by special mechanisms within the system. Therefore, traditional Ethernet cannot guarantee the effective transmission of special data. Time-Triggered Ethernet (TTE) introduces time synchronization technology and the concept of time triggering into traditional Ethernet, creating a separate channel for time-triggered (TT) services. This service is triggered strictly according to the system time, ensuring the high priority transmission of important data within the system.

[0003] As network systems become more diverse, network loads are increasing, making network operation and maintenance more difficult. Consequently, the demand for network testing is increasing. Traditional network testing equipment can only test event-triggered (ET) services, but cannot test TTE network devices, making it impossible to guarantee the reliability of time-triggered services in TTE network devices.

[0004] Satellites, as complex systems, exchange information across the satellite through a TTE network. Multiple onboard units and subsystems transmit data within the TTE network, and the entire satellite is constructed using multiple network switches in a ring-like network architecture. Testing of each onboard unit and subsystem is typically completed during the self-test phase of each subsystem, without the necessary conditions or environment for system-level testing. After completing service planning for the system-level network, verifying that this service plan meets system requirements and that the switching network functions properly becomes a key component of system-level testing.

[0005] The time delay from the sender to the receiver is called the CT frame delay in the system. CT frame transmission jitter is the difference between the maximum and minimum end-to-end transmission delays of TT frames. Traditional TTE network delay and jitter are calculated simply by recording the send and receive times and comparing them. However, there is a high probability of system time differences between the two end systems, making it difficult to ensure time synchronization. Therefore, the calculated delay and jitter include the time difference between the two systems and do not accurately reflect data transmission delay. Summary of the Invention

[0006] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a delay and jitter testing method and system for ring-type time-triggered Ethernet, which solves the time difference problem between systems and can accurately test the delay of sending CT frames between two end systems in a system.

[0007] To achieve the above object, the present invention provides a method for testing the delay and jitter of a ring-type time-triggered Ethernet network, comprising the following steps:

[0008] Step S1: constructing a ring-type TTE network test architecture, wherein the architecture includes a ring topology formed by at least three switches, and at least two end systems are respectively connected to different switch ports;

[0009] Step S2: End system a sends a test frame to end system b, and records the sending time t1 and the receiving time t2; end system b returns the test frame to end system a, and records the sending time t3 and the receiving time t4;

[0010] Step S3: Calculate the transmission delay from end system a to end system b according to the transmission delay calculation formula delay = [(t2-t1)+(t4-t3)] / 2;

[0011] Step S4: Repeat steps S1 to S3 to perform multiple tests, and calculate the difference between the maximum and minimum delays as transmission jitter.

[0012] According to a technical solution of the present invention, in the ring topology, the connected switches are connected via full-duplex ports to form a closed loop, and the data transmission directions include clockwise and counterclockwise paths.

[0013] According to a technical solution of the present invention, the test frame is a CT service frame, and the sending period, frame length and receiving time window are configured according to the service planning requirements of the service planning table.

[0014] According to a technical solution of the present invention, it also includes:

[0015] Step S5: Calculate an average value based on the transmission delays obtained from multiple tests, and use the average value of the transmission delay as an indicator describing the CT frame delay on the link.

[0016] According to a technical solution of the present invention, the calculation of the transmission jitter specifically includes:

[0017] Step S41: Obtain a set of delay data from multiple tests;

[0018] Step S42: Extract the maximum delay value max , minimum delay min ;

[0019] Step S43, calculate the jitter value: jitter = delay max -delay min ;

[0020] Step S44: Generate a delay distribution histogram and a jitter trend report.

[0021] According to a technical solution of the present invention, it is applicable to a small local area network.

[0022] According to one aspect of the present invention, a test system for implementing the delay and jitter testing method of a ring-type time-triggered Ethernet as described in any one of the above technical solutions is proposed, comprising:

[0023] A ring-type TTE network test architecture, comprising a ring topology formed by at least three switches, and at least two end systems connected to different switch ports;

[0024] Control module, used to configure test frame parameters, trigger test processes and manage transmission paths;

[0025] Statistical analysis module, used to calculate delay and jitter.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a method and system for delay and jitter testing of a ring-type time-triggered Ethernet (TTE) network. The method adopts a ring connection mode of at least three switches, supports dynamic configuration of clockwise and counterclockwise bidirectional data transmission paths, and can cover all potential transmission links of a multi-layer cascade network, thus overcoming the limitation that traditional single-switch or simple topology test equipment cannot verify the performance of a ring-type TTE network. In terms of testing method, by recording the sending and receiving timestamps of bidirectional test frames between end systems, the clock deviation between end systems is eliminated, and the delay calculation error is controlled to the microsecond level, which can greatly improve the accuracy compared with the traditional one-way time difference calculation method. In jitter testing, the difference between the maximum and minimum values of the delay data set based on repeated tests is extracted, and combined with the statistical analysis module, a delay distribution histogram and jitter trend report are generated, which can intuitively reflect the stability of network transmission and meet the stringent requirements for network determinism in high-real-time scenarios such as satellite whole-satellite testing.

[0028] The present invention solves the time difference problem between systems and can accurately test the delay of sending CT frames between two end systems in a system. At the same time, the present invention can ignore the number of switch forwarding levels in the system and realize system-level indicator testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0030] Figure 1 Schematically showing a ring topology diagram according to an embodiment of the present invention;

[0031] Figure 2 Schematically showing a CT frame transmission delay test principle diagram according to an embodiment of the present invention;

[0032] Figure 3 Schematically showing a schematic diagram of the CT frame transmission delay test principle according to an embodiment of the present invention;

[0033] Figure 4 Schematically illustrates the CT frame transmission jitter test principle according to one embodiment of the present invention;

[0034] Figure 5 Schematically shows a test system architecture diagram according to an embodiment of the present invention;

[0035] Figure 6 The figure schematically shows a flow chart of delay and jitter testing of a ring-type time-triggered Ethernet according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0037] The data transmitted by TTE is divided into three key services, namely time-triggered service, rate-constrained (RC) service, and best-effort (BE) service.

[0038] TT services: TT service transmission is based on a unified clock maintained across the entire network and inter-node clock synchronization. Service transmission and reception are strictly executed periodically according to the corresponding time schedule, ensuring the time determinism and reliability of data transmission. The system specifies a specific transmission link, transmission cycle, data frame length, transmission time, and reception time window for each TT service.

[0039] RC service: RC service is the second-priority service in the network, lower than TT service. It uses full-duplex switching mode to generate data by establishing periodic communications that maximize bandwidth utilization based on user needs, and filters out data frames that exceed the frame length range and do not meet the virtual link standards, thereby ensuring limited transmission delay and bandwidth in complex network environments.

[0040] BE service: BE service is based on traditional Ethernet and has the lowest priority among the three key services. Therefore, BE service can only use the remaining network bandwidth for transmission under the premise that TT service and RC service occupy the network bandwidth first. This makes it impossible for BE service to guarantee service quality. Under extreme conditions, data frames cannot reach the receiving end because the bandwidth may be occupied by TT service and RC service during data transmission. There is no time guarantee, so only compatible network services are provided.

[0041] like Figures 1 to 6 As shown, a method for testing the delay and jitter of a ring-type time-triggered Ethernet according to the present invention comprises the following steps:

[0042] Step S1: constructing a ring-type TTE network test architecture, wherein the architecture includes a ring topology formed by at least three switches, and at least two end systems are respectively connected to different switch ports;

[0043] When building a TTE system-level product, if the system is large and includes multiple end nodes, and a single switch cannot integrate all of them, a ring configuration is needed to increase system scale. The ring configuration is one of the most basic and simplest switch network structures. In a ring configuration, multiple switches are connected together through their ports, forming a ring network topology. In this configuration, data is passed sequentially between switches, with each switch solely responsible for forwarding data from one port to another until the data reaches its destination.

[0044] The ring approach has the advantage of being simple and easy to use, making it suitable for small local area networks. However, it also has some disadvantages. First, data transmission on the ring link may experience delays, affecting network performance. This is especially true in TTE networks. Because each switch has a strictly defined windowing period for TTE services, ensuring that data is transmitted within this windowing period across multiple switches is crucial for ensuring accurate data transmission. Second, if a switch in the ring link fails, communication across the entire network may be interrupted.

[0045] Reference Figure 1In the ring topology described in this invention, connected switches form a closed loop via full-duplex ports, with data transmission occurring in both clockwise and counterclockwise directions. By enabling two end systems to transmit and receive data within the ring TTE network, the correctness of the system service plan can be verified, while also ensuring the transmission performance of the system hardware.

[0046] Step S2: End system a sends a test frame to end system b, and records the sending time t1 and the receiving time t2; end system b returns the test frame to end system a, and records the sending time t3 and the receiving time t4;

[0047] Step S3: Calculate the transmission delay from end system a to end system b according to the transmission delay calculation formula delay = [(t2-t1)+(t4-t3)] / 2;

[0048] The CT frame transmission delay test method and principle are as follows:

[0049] like Figure 2 As shown in the schematic diagram of the CT frame transmission delay test, when testing the delay of sending CT frames from end system a to end system b, the test system controls end system a to send test packets, end system b receives the test packets, and then end system b forwards the received data packets back to end system a.

[0050] When end system a sends a test packet, it records the sending time t1; when end system b receives the test packet, it records the receiving time t2. Due to the transmission delay and clock offset between the two end systems, we can get formula (1):

[0051] t2- t1=delay + offset (1)

[0052] Then let end system b send a test packet and record the sending time t3; when end system a receives the test packet, record the receiving time t4. If the delay between the two end systems is symmetrical, we can get formula (2):

[0053] t4- t3=delay – offset (2)

[0054] The specific principle is as follows Figure 3 As shown. The above two equations can be used to obtain the transmission delay between end systems a and b, as shown in formula (3):

[0055] delay =[( t2- t1)+( t4- t3)] / 2 (3)

[0056] Step S4: Repeat steps S1 to S3 to perform multiple tests, and calculate the difference between the maximum and minimum delays as transmission jitter.

[0057] The CT frame transmission jitter test method and principle are as follows:

[0058] The transmission jitter CT frame is the difference between the maximum and minimum transmission delays between two end systems. The CT frame delay test method in step S3 is to perform multiple delay tests and calculate the maximum delay delay. max , minimum delay min .

[0059] The calculation of transmission jitter specifically includes:

[0060] Step S41: Obtain a set of delay data from multiple tests;

[0061] Step S42: Extract the maximum delay value max , minimum delay min ;

[0062] Step S43, calculate the jitter value: jitter = delay max -delay min ;

[0063] Step S44: Generate a delay distribution histogram and a jitter trend report.

[0064] By designing a CT frame transmission jitter test method, the transmission jitter of all CT frames in the system can be effectively obtained.

[0065] In some embodiments of the present invention, the test frame is a CT service frame, and the sending period, frame length and receiving time window are configured according to the service planning requirements of the service planning table.

[0066] In some embodiments of the present invention, further comprising:

[0067] Step S5: Calculate an average value based on the transmission delays obtained from multiple tests, and use the average value of the transmission delay as an indicator describing the CT frame delay on the link.

[0068] Through the delay test method in step S3, the clock deviation between the two independent end systems can be successfully eliminated, and the delay of sending TT frames between end system a and end system b can be accurately calculated. n , calculate the average value of the TT frame transmission delay between end system m and end system n. The average value calculation method is as shown in formula (4).

[0069] delay = (delay1+ delay2+…+delay n ) / n (4).

[0070] By designing a CT frame transmission delay test method, the problem of system time difference between end systems can be effectively solved, and the transmission delay of the TTE frame in this system can be accurately tested and measured.

[0071] According to one aspect of the present invention, a test system for implementing the delay and jitter testing method of a ring-type time-triggered Ethernet as described in any one of the above technical solutions is proposed, comprising:

[0072] A ring-type TTE network test architecture, comprising a ring topology formed by at least three switches, and at least two end systems connected to different switch ports;

[0073] Control module, used to configure test frame parameters, trigger test processes and manage transmission paths;

[0074] Statistical analysis module, used to calculate delay and jitter.

[0075] like Figure 5 As shown, in order to accurately verify the correctness of the above test method, a TTE network communication system is designed. The system includes a TTE multi-hop topology ring network, end system boards, and control and statistical analysis equipment. The specific design includes three switches forming a ring switching network and two end systems forming a transceiver link. The connection relationship is as follows Figure 5 As shown in the figure, three industrial switches supporting the TTE protocol (such as model: TTE-SW2000) are used and connected in sequence through full-duplex ports to form a closed ring topology.

[0076] Based on the service planning requirements in the service planning table, end system A and end system B can be plugged into different switch ports to test the latency and jitter on different service transmission paths.

[0077] To test the CT frame delay between end system a and end system b, follow these steps:

[0078] 1) End system a sends a dedicated test frame and records the system sending time t1;

[0079] 2) End system b receives the dedicated test frame and records the system reception time t2;

[0080] 3) End system b forwards the received dedicated test frame and records the system sending time t3;

[0081] 4) End system a receives the professional test frame and records the system receiving time t4;

[0082] 5) Calculate delay;

[0083] 6) Repeat tests 1) to 4) multiple times to collect multiple delay data and system jitter statistics.

[0084] The verification test system is used to implement a test scenario of multiple switches and multiple terminal systems to verify the relevant test methods of the present invention. The delay input is shown in Table 1 below.

[0085]

[0086] Table 1

[0087] Based on the above latency test data, the jitter is 12716.5 us by subtracting the maximum latency (29766.0 us) from the minimum latency (17049.5 us).

[0088] This paper analyzes key indicators of CT frames in TTE networks, proposes system-level testing methods for CT frame transmission delay and transmission jitter, and builds a test platform to test and verify the test solutions for these indicators. The results demonstrate that the proposed test method is accurate, effective, and highly operational, accurately reflecting the transmission performance of TTE cascaded network systems. This paper is particularly suitable for TTE network transmission performance testing in full-satellite testing and system-level testing and verification scenarios.

[0089] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention. Therefore, the present invention is not limited to the above-mentioned specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. A method for testing the delay and jitter of a ring-type time-triggered Ethernet, characterized in that: The following steps are involved: Step S1: constructing a ring-type TTE network test architecture, wherein the architecture includes a ring topology formed by at least three switches, and at least two end systems are respectively connected to different switch ports; Step S2: End system a sends a test frame to end system b, and records the sending time t1 and the receiving time t2; end system b returns the test frame to end system a, and records the sending time t3 and the receiving time t4; Step S3: Calculate the transmission delay from end system a to end system b according to the transmission delay calculation formula delay = [(t2-t1)+(t4-t3)] / 2; Step S4: Repeat steps S1 to S3 to perform multiple tests, and calculate the difference between the maximum and minimum delays as transmission jitter.

2. The method for testing the delay and jitter of a ring-type time-triggered Ethernet according to claim 1, wherein: In the ring topology, the connected switches are connected via full-duplex ports to form a closed loop, and the data transmission directions include clockwise and counterclockwise paths.

3. The method for testing the delay and jitter of a ring-type time-triggered Ethernet according to claim 1, wherein: The test frame is a CT service frame, and the sending period, frame length and receiving time window are configured according to the service planning requirements of the service planning table.

4. The method for testing the delay and jitter of a ring-type time-triggered Ethernet according to claim 1, wherein: Also includes: Step S5: Calculate an average value based on the transmission delays obtained from multiple tests, and use the average value of the transmission delay as an indicator describing the CT frame delay on the link.

5. The method for testing the delay and jitter of a ring-type time-triggered Ethernet according to claim 1, wherein: The calculation of the transmission jitter specifically includes: Step S41: Obtain a set of delay data from multiple tests; Step S42: Extract the maximum delay value max , minimum delay min ; Step S43, calculate the jitter value: jitter = delay max -delay min ; Step S44: Generate a delay distribution histogram and a jitter trend report.

6. The method for testing the delay and jitter of a ring-type time-triggered Ethernet according to claim 1, wherein: Suitable for small local area networks.

7. A test system for implementing the delay and jitter test method of a ring-type time-triggered Ethernet according to any one of claims 1 to 6, characterized in that: include: A ring-type TTE network test architecture, comprising a ring topology formed by at least three switches, and at least two end systems connected to different switch ports; Control module, used to configure test frame parameters, trigger test processes and manage transmission paths; Statistical analysis module, used to calculate delay and jitter.

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