(DoIP) Diagnostics Over Internet Protocol Explained

What is DoIP and what does it mean?

DoIP, or Diagnostics over Internet Protocol, is a communication protocol that enables remote diagnostics of automobiles and other complicated systems.

As the Internet of Things (IoT) expands, more and more devices are connected to the internet, making remote diagnosis and repairs possible.

The DoIP protocol was essentially introduced to enable communication between external tester tools and electronics control units (ECUs). Today, DoIP is an important protocol in the automobile industry since it allows you to retrieve diagnostic information from your vehicle's onboard computer system through the internet. This is especially beneficial when your car is on the road or in a remote area.

Furthermore, you can use DoIP to quickly and easily detect problems with a vehicle's engine, gearbox, brakes, and other vital components. You can then use this information to create a repair plan, purchase components, and carry out repairs without ever touching the vehicle.

While DoIP is most often employed in the automobile sector, it has the potential to be applied in a variety of other industries. It may, for example, be used to troubleshoot industrial machinery, medical equipment, or even household appliances.

Keep on reading, to find out how it works.

What is the UDS protocol (ISO 14229)?

According to the ISO 14229 standard, Unified Diagnostic Services (UDS) is a protocol used by diagnostic systems to communicate with ECUs in vehicles.

UDS combines standards such as KWP 2000 (ISO 14230) or diagnostics on CAN (ISO 15765) and is independent of vehicle manufacturers. UDS is nowadays one of the most properly used standards for diagnostic protocols.

The Ethernet layer does not support a Bus structure (like the one in CAN), which means you need to switch it for every network node. The architecture of the UDS protocol is based on the Open System Interconnection (OSI), the same as in the CANopen protocol and it means that the UDS software stack has a layered architecture.

A very important function of the UDS software stack to mention is that it stores fault code in the memory of ECU for every issue that happened in the vehicle and will transfer it to the client.

By doing that, you will make sure that ethernet-based DoIP supports rates up to 100mbps (500kbps in CAN).

What Is Ethernet/IP?

Ethernet is a form of connecting computers in a local area network (LAN). It has been commonly used since the 1990s and the idea behind it is that multiple computers have access to it and can send data at any time.

Remember, it’s not the same as the Internet. The Internet is a communication protocol for a global network whereas Ethernet is a communication protocol for a local area network.

IP, or IP address, is an internet protocol address, which is an address assigned to each device connected to a computer network that uses the internet.

How DoIP enables Remote Vehicle Diagnostics?

DoIP getaway enables remote vehicle diagnostics capabilities in all ECUs connected to it. It saves the cost and the effort of integrating the DoIP protocol stack in every electronic control unit for the car separately.

A diagnostic tester tool is being used, as it sends diagnostic requests to the vehicle through the ethernet and it receives a diagnostic response.

The increasing connection has turned the next generation of cars into "computers on wheels. In contrast to the traditional automotive network backbone of CAN buses, Ethernet is expected to replace them shortly.

The use of Automotive Ethernet allows for more efficient data transfer in today’s connected automobiles as well as those of the future.

The difference between UDS on IP and UDS on CAN

UDS on IP (LAN/WLAN):

• UDS application layer (ISO 14229-5).

• DoIP transport layer (ISO 13400-2).

• Ethernet physical layer (IEEE 802.3).

UDS on CAN (CAN):

• UDS application layer (ISO 14229-3).

• CAN transport layer (ISO 15765-2).

• CAN physical layer (ISO 11898).

So ISO 14229-5 standard defines the implementation of UDS on IP and the ISO 14229-3 standard defines the implementation of UDS on CAN.

In other words, UDS on IP is more efficient than CAN Bus in many aspects, such as greater latency time of data transmission, being able to handle larger amounts of data, data format making it less prone to error, and more.

Advantages of Ethernet MAC layer of DoIP stack solution:

• Light weighted and simple shielded structured cable.

• Low-cost technology that allows high bandwidth for data communication.

• Flexible communication platform.

Using the ISO 14229-5 application layer, the implementation of UDS and IP is being done. The DoIP connection can be set up to run manually or automatically after each time that vehicle is online.

Features of ISO 13400-2:2012

ISO 13400-2:2012 determines requirements for the vehicle gateway and test equipment. ISO 13400-2 is very important for diagnostic communication and you can find its features below:

• Vehicle announcement and vehicle discovery.

• Vehicle network integration.

• Error handling.

• Vehicle basic status information retrieval.

• Connection establishment.

• Data routing.

ISO 13400-2:2012 might have additional optional features such as:

• DoIP entity firewall capabilities.

• DoIP entity status monitoring.

Next-generation vehicles will enable powerful connectivity and advanced telematics services. DoIP is becoming more common and is being used more often than before.

It is also connected to the development of the manufacturers, in the process of developing an intelligent car. It might also play a very important role in the development of IoT platforms. Due to the limited resources in embedded devices, adopting lightweight TCP/IP is necessary.

How to take advantage of DoIP with the AutoPi

Our newest device, AutoPi TMU CM4, enables you to upgrade the device to allow support for DoIP. Furthermore, together with our cloud management platform, provides businesses with DoIP/UDS add-on, which can be installed through the platform.

Interested in the DoIP feature? Get in touch with us and we can discuss your project.