Diagnostics Over Internet Protocol (DoIP) Explained

Diagnostics Over Internet Protocol (DoIP) Explained

First of all, you probably want to know what DoIP means.


DoIP stands for Diagnostics over Internet Protocol and it facilitates the use of automotive diagnostic services exposed through UDS over TCP/IP on an Ethernet network.


Compared to conventional CAN based diagnostics, DoIP allows for much faster data transfer rates at a low hardware cost. This makes DoIP interesting for today’s car manufacturers.



An illustrated explanation of what doip means


What is UDS?

According to the ISO 14229 standard, Unified Diagnostic Services (UDS) is a protocol used by diagnostic systems to communicate with electronic control units (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 Bus structure (like the one in CAN), which means you need to switch it for every network node.


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 together 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. 



What Does DoIP mean?

DoIP is an acronym for Diagnostics Over Internet Protocol. DoIP protocol was introduced to enable communication between an external tester tool and electronic control units (ECU).


In other words, remote vehicle diagnostics. DoIP requirements are determined in ISO 13400.



An illustration on how diagnostics over internet protocol work like



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 DoIP protocol stack in every ECU separately.


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


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


In other words, UDS on IP is more efficient than CAN in many aspects, such as greater latency time of data transmission, able to handle larger amounts of data, data format makes 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. 


A visual explanation of doip


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 it 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

 


Diagnostics over internet protocol are becoming more common and are being used more often than before.


We definitely see a big potential within the automotive industry and it might even become one of the main automotive industry trends in the upcoming years.


It is also connected to the development of the manufacturers, in the process of developing an intelligent car


Do you want to know how AutoPi can help and assist you with Diagnostics Over Internet Protocol? Contact us on sales@autopi.io



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