Introduction to DoIP Protocol Timing and Communication Parameters
The DoIP (Diagnostics over Internet Protocol) is a network communication protocol used in the automotive industry for diagnostic services. The DoIP Protocol timing and communication parameters are a set of guidelines that determine how DoIP entities interact and communicate with each other.
The timing and communication parameters of the DoIP protocol are critical to ensure effective communication between the diagnostic tester and the ECU. The communication parameters define the format of the data packets exchanged between the two devices, while the timing parameters define the timing requirements for the communication.
The DoIP protocol uses the Transmission Control Protocol (TCP) for reliable communication between the tester and the ECU. The protocol defines various timing parameters such as the maximum delay for response, minimum duration between data frames, and maximum time for response to a diagnostic message. These timing parameters ensure that the communication between the two devices is reliable and efficient.
DoIP Protocol Timing Parameters
One of the critical aspects of the DoIP protocol is timing. Timing parameters define the time limits for various operations, such as establishing a connection, transmitting data, keeping a connection alive, and receiving responses. The timing parameters in DoIP protocol are related to the time it takes for data to be transmitted between two devices using the protocol.
Why do we need Timing Parameters in DoIP Protocol?
DoIP Timing parameters ensure that data is transmitted efficiently and reliably between different ECUs in the vehicle. If timing parameters are not set correctly, it can lead to delays in data transmission, data corruption, or even complete failure of the diagnostic communication. It mostly similar to UDS Protocol for DoCAN standard.
The different timing parameters in DoIP include connection timeout, transmission timeout, keep-alive timeout, response timeout, and inter-frame gap. Connection timeout defines the maximum time allowed to establish a connection between two devices. Transmission timeout defines the maximum time allowed to transmit a message from one device to another. Keep-alive timeout defines the maximum time allowed to keep a connection alive. Response timeout defines the maximum time allowed to receive a response after sending a request. Inter-frame gap defines the minimum time delay between two successive frames transmitted on the network.
Properly setting and configuring the timing parameters is essential for ensuring the reliable and efficient operation of the DoIP protocol. The exact timing parameters used may vary depending on the specific application requirements and the protocol standards used.
The following are the reasons why timing parameters are essential in the DoIP protocol:
- Control of Latency: Timing parameters help control the latency of the communication between the ECUs. Latency refers to the delay between the transmission and reception of data. By setting the appropriate timing parameters, the latency can be controlled to ensure that the communication is timely and efficient.
- Prevent Data Loss: Timing parameters help prevent data loss during the transmission of data between ECUs. The timing parameters ensure that data packets are transmitted and received within a specific time frame. This ensures that the data is not lost or corrupted during transmission.
- Efficient Communication: Timing parameters help in optimizing the use of network resources. By setting the appropriate timing parameters, the communication between the ECUs can be optimized to make the most efficient use of the network resources.
- Error Handling: Timing parameters are also used in error handling. They help detect and recover from transmission errors that can occur during the communication between the ECUs. By setting the appropriate timing parameters, errors can be detected and corrected before they lead to communication failures.
DoIP Protocol Communication Parameters
DoIP (Diagnostic over Internet Protocol) is a communication protocol used in the automotive industry for diagnostic purposes. It defines various communication parameters that specify how data is transmitted between different electronic control units (ECUs) in a vehicle.
Why do we need Communication Parameters in DoIP Protocol?
The following are the reasons why communication parameters are needed in the DoIP protocol:
- Bandwidth Management: DoIP protocol supports various types of diagnostic communication. Communication parameters help in managing the bandwidth requirements of the different types of diagnostic communication, thereby ensuring that the communication is efficient.
- Quality of Service (QoS) Management: The DoIP protocol supports multiple communication channels, each with its own QoS requirements. Communication parameters help in managing the QoS requirements of the different communication channels, thereby ensuring that the communication is reliable.
- Security: DoIP protocol supports secure communication between the ECUs. Communication parameters help in managing the security requirements of the communication, such as encryption and authentication.
- Error Handling: Communication parameters help in managing errors that can occur during the communication between the ECUs. They enable the detection and correction of errors, thereby ensuring that the communication is reliable.
These DoIP Protocol Timing and Communication parameters include:
| Timing parameter | Description | Parameter Value |
|---|---|---|
| A_DoIP_Ctrl | The timeout duration indicates the maximum waiting period for the external test equipment to receive a reply for a previously transmitted UDP message. This duration encompasses the time required to wait and accumulate multiple responses for a prior broadcast (UDP exclusive). | Timeout: 2 s |
| A_DoIP_Announce_Wait | The specified timing parameter governs the duration for which a DoIP entity initially awaits before responding to a vehicle identification request, and the duration for which it waits before transmitting a vehicle announcement message after configuring a valid IP address. This timing parameter is randomly determined within the range of the minimum and maximum values. | Random Time: 0…500 ms |
| A_DoIP_Announce_Interval | This timing parameter specifies the time between the vehicle announcement messages that are sent by the DoIP entities after a valid IP address has been configured. | Delay time: 500 ms |
| A_DoIP_Announce_Num | The specified parameter denotes the quantity of vehicle announcement messages that the DoIP entity transmits subsequent to configuring a valid IP address. | Repetition: 3 times |
| A_DoIP_Diagnostic_Message | The interval between the reception of the final byte of a DoIP diagnostic message and the transmission of the acknowledgment (ACK) or negative acknowledgment (NACK) is defined as the timeout duration. If the timeout expires, the request or response will be deemed as lost, and the request may be reattempted. | Performance time: 50 ms Timeout: 2 s |
| T_TCP_General_Inactivity | The timeout duration designates the upper limit of inactivity on a TCP_DATA socket, where neither data is transmitted nor received, before the corresponding DoIP entity closes the socket. | Timeout: 5 min |
| T_TCP_Initial_Inactivity | The timeout duration denotes the maximum period of inactivity that follows the establishment of a TCP_DATA socket. If there is no routing activation during this specified interval, the DoIP entity will close the TCP_DATA socket. | Timeout: 2 s |
| T_TCP_Alive_Check | The timeout duration indicates the maximum waiting period for a DoIP entity to receive a response to an alive check request sent through the TCP_DATA socket. This timer will expire even if the underlying TCP stack cannot deliver the alive check request message. | Timeout: 500 ms |
| A_Processing_Time | The timeout interval pertains to the duration between the external test equipment transmitting DoIP messages that do not require a response but may require some processing time. Consequently, the external test equipment must await at least A_Processing_Time before sending another request to the same DoIP entity. | Timeout: 2 s |
| A_Vehicle_Discovery_Timer | This is a timer designated per vehicle for offboard usage. Its function is to determine the duration that a vehicle has to perform VIN/GID synchronization among all the DoIP entities. Commencement of the vehicle discovery timer is only permissible upon receipt of a vehicle announcement or vehicle identification response message, which includes a VIN/GID synchronization status code “incomplete” (0x10) and a valid VIN or GID, by the external test equipment. | Timeout: 5 s |
In conclusion, the DoIP protocol’s timing and communication parameters are critical to the successful exchange of diagnostic and programming data between the tester and the ECU. Adherence to these parameters is essential to ensure that the communication is reliable, efficient, and meets the industry standards.
