UDS OSI Model

Overview of OSI model for UDS protocol.

UDS Standards

UDS is defined by multiple standards which are the main source of information and requirements about this protocol. Full list of standards is included in the table below:

OSI Layer

Common

CAN

FlexRay

Ethernet

K-Line

LIN

Layer 7 Application

ISO 14229-1

ISO 27145-3

ISO 14229-3

ISO 14229-4

ISO 14229-5

ISO 14229-6

ISO 14229-7

Layer 6 Presentation

ISO 27145-2

Layer 5 Session

ISO 14229-2

Layer 4 Transport

ISO 27145-4

ISO 15765-2

ISO 10681-2

ISO 13400-2

Not applicable

ISO 17987-2

Layer 3 Network

Layer 2 Data

ISO 11898-1

ISO 17458-2

ISO 13400-3

ISO 14230-2

ISO 17987-3

Layer 1 Physical

ISO 11898-2

ISO 11898-3

ISO 17458-4

ISO 14230-1

ISO 17987-4

where:

  • OSI Layer - OSI Model Layer for which standards are relevant

  • Common - standards mentioned in this column are always relevant for UDS communication regardless of bus used

  • CAN - standards which are specific for UDS on CAN implementation

  • FlexRay - standards which are specific for UDS on FlexRay implementation

  • Ethernet - standards which are specific for UDS on IP implementation

  • K-Line - standards which are specific for UDS on K-Line implementation

  • LIN - standards which are specific for UDS on LIN implementation

Protocol Data Units

Each layer of OSI Model defines their own Protocol Data Unit (PDU). To make things simpler for the users and our developers, in the implementation we distinguish following PDUs:

  • Application Protocol Data Unit (A_PDU) - called diagnostic message or UDS Message in the implementation and documentation. More information about A_PDU can be found in:

  • Network Protocol Data Unit (N_PDU) - called packet in the implementation and documentation. More information about N_PDU can be found in:

  • Data Protocol Data Unit (D_PDU) - called frame in the implementation and documentation. We do not have any internal frames documentation. Implementation of frames is usually provided by external packages.

UDS PDUs

UDS Protocol Data Units on different layers of OSI Model.