DoIP architecture

DoIP is a vehicle diagnostic technology using an Ethernet network. Ethernet provides higher speed (up to 100 Mbit) and channel bandwidth.
Ethernet lines are output to a standard OBD2 connector using two twisted pairs and an additional Wake-Up line that notifies the car that diagnostic equipment is connected. At the same time, the CAN diagnostic bus is preserved for compatibility with diagnostic equipment of previous generations.

DoIP diagnosis does not require expensive specialized equipment. A fairly simple OBD2-Ethernet adapter. The photo below shows the Internet interface from a Volvo XC90 car with DoIP support. For the convenience of working with it in laboratory conditions, an ordinary Ethernet cable is connected to it, which made it possible to connect this control unit directly to a computer.

DoIP gateway

Speaking formally: DoIP is a transport layer for the UDS diagnostic protocol, which can work on top of other physical interfaces: CAN , K-Line , FlexRay .

Since in the car, all control units are connected by CAN or FlexRay networks, their interaction with diagnostic equipment is ensured by means of a special module - a gateway, or an inter-network interface. Ethernet from a standard OBD2 diagnostic block goes to the gateway port, which in turn broadcasts the protocol to CAN or FlexRay.

Link to the original, real professionals work here.