PROTOCOL · TRANSPORT LAYER · 2012-present
DoIP protocol
Diagnostics over Internet Protocol (ISO 13400).
What is DoIP?
DoIP (Diagnostics over Internet Protocol, ISO 13400) carries UDS application-layer requests over Ethernet (typically 100BASE-T1 single-pair automotive Ethernet, or vehicle-side 1000BASE-T) instead of CAN. Used on modern BMW G-chassis, Mercedes MRA (W213, W222), VAG MQB Evo, and as the transport for over-the-air (OTA) updates.
Key characteristics
- Application layer: UDS (same SIDs as CAN-UDS).
- Transport: Ethernet via TCP (for guaranteed delivery) or UDP (for discovery).
- Vehicle Identification: UDP port 13400, broadcast on local subnet.
- Routing Activation: TCP/13400, authenticates the tester to specific ECUs.
- Used for full vehicle reads on modern BMW (ENET cable) and for OTA flash on Tesla / Mercedes EQE / VAG MQB Evo.
- Bench-mode flashing of CAN-FD ECUs sometimes uses DoIP instead of CAN-FD for speed.
DoIP service IDs / frame structure
| ID / Code | Name | Purpose |
|---|---|---|
UDP 13400 | Vehicle Identification | Tester broadcasts for nearby vehicles |
TCP 13400 | Routing Activation | Tester authenticates to ECU |
TCP 13400 | UDS payload | Application-layer UDS over TCP |
0x0001 | Generic Header NACK | Header error indicator |
0x0005 | Routing Activation Request | Tester→vehicle authenticate |
0x0006 | Routing Activation Response | Vehicle→tester accept/reject |
0x8001 | Diagnostic Message | UDS payload carrier |