ISO/DIS 14229-2

Road vehicles -- Unified diagnostic services (UDS)

Véhicules routiers -- Services de diagnostic unifiés (SDU)

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 14229-2
ISO/TC 22/SC 31 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-02-11 2021-05-06
Road vehicles — Unified diagnostic services (UDS) —
Part 2:
Session layer services
Véhicules routiers — Services de diagnostic unifiés (SDU) —
Partie 2: Séquence des couches de services
ICS: 43.180
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
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WHICH REFERENCE MAY BE MADE IN
Reference number
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ISO/DIS 14229-2:2021(E)
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TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
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PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
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ISO/DIS 14229-2:2021(E)
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© ISO 2021

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ISO/DIS 14229-2:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 2

4.1 Symbols ......................................................................................................................................................................................................... 2

4.2 Abbreviated terms ............................................................................................................................................................................... 2

5 Conventions ............................................................................................................................................................................................................... 2

6 Session layer services ...................................................................................................................................................................................... 3

6.1 Service interface .................................................................................................................................................................................... 3

6.2 Service interface parameters ...................................................................................................................................................... 3

6.3 Service interface primitives ......................................................................................................................................................... 3

7 Service interface (SI) definition from application layer to session layer ..................................................5

7.1 SI — S_Data.req, S_Data.ind, and S_Data.conf service interface .................................................................... 5

7.2 SI — S_Data.req, S_Data.ind, and S_Data.conf service interface parameter mapping ................ 5

7.3 SI — S_PDU mapping onto T_PDU and vice versa for message transmission .................................. 6

7.4 SI — S_Data.req....................................................................................................................................................................................... 7

7.5 SI — S_Data.conf .................................................................................................................................................................................... 7

7.6 SI — S_Data.ind ....................................................................................................................................................................................... 7

8 Service primitive parameters (SPP) ................................................................................................................................................. 8

8.1 SPP – General ............................................................................................................................................................................................ 8

8.2 SPP – Data type definitions .......................................................................................................................................................... 8

8.3 SPP – S_Mtype, session layer message type ................................................................................................................... 8

8.4 SPP – S_TAtype, session layer target address type ................................................................................................... 8

8.5 SPP – S_TA, session layer target address .......................................................................................................................... 9

8.6 SPP – S_SA, session layer source address ......................................................................................................................... 9

8.7 SPP – S_AE, session layer address extension ................................................................................................................. 9

8.8 SPP – S_Length, session layer length of S_Data ........................................................................................................... 9

8.9 SPP – S_Data, session layer data of PDU ............................................................................................................................ 9

8.10 SPP – S_Result, session layer result ....................................................................................................................................10

9 Timing parameter definition ................................................................................................................................................................10

9.1 General application timing considerations .................................................................................................................10

9.1.1 Server ......................................................................................................................................................................................10

9.1.2 Client .......................................................................................................................................................................................11

9.2 Application timing parameter definitions – defaultSession .........................................................................12

9.3 Example for P4 without enhanced response timing ...............................................................................17

Server

9.4 Example for P4 with enhanced response timing........................................................................................18

Server

9.5 Session timing parameter definitions for the non-default session .........................................................20

9.6 Client and server timer resource requirements ......................................................................................................22

9.7 Error handling ......................................................................................................................................................................................22

10 Timing handling during communication .................................................................................................................................24

10.1 Physical communication ..............................................................................................................................................................24

10.1.1 Physical communication during defaultSession – without SOM.ind ................................24

10.1.2 Physical communication during defaultSession – with SOM.ind ........................................24

10.1.3 Physical communication during defaultSession with enhanced response

timing ........................................................................................................................................... ...........................................25

10.1.4 Physical communication during a non-default session ...............................................................27

10.2 Functional communication ........................................................................................................................................................33

10.2.1 Functional communication during defaultSession – without SOM.ind .........................33

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ISO/DIS 14229-2:2021(E)

10.2.2 Functional communication during defaultSession – with SOM.ind ..................................35

10.2.3 Functional communication during defaultSession with enhanced

response timing – with SOM.ind .....................................................................................................................36

10.2.4 Functional communication during non-default session – with SOM.ind .....................37

10.3 Minimum time between client request messages .................................................................................................41

Annex A (informative) T_PDU interface ..........................................................................................................................................................49

Annex B (informative) Vehicle diagnostic OSI layer architecture examples ............................................................50

Bibliography .............................................................................................................................................................................................................................54

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ISO/DIS 14229-2:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31,

Data communication.

This third edition cancels and replaces the second edition (ISO 14229-2:2012), which has been

technically revised.
The main changes compared to the previous edition are as follows:
— restructured the document;
— introduction of requirement numbers and names;

— technical content improvements based on implementation feedback from the automotive industry.

A list of all parts in the ISO 14229 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/DIS 14229-2:2021(E)
Introduction

ISO 14229 has been established in order to define common requirements for diagnostic systems,

whatever the serial data link is.

To achieve this, ISO 14229 is based on the Open Systems Interconnection (OSI) Basic Reference Model

[1] [2]

in accordance with ISO 7498-1 and ISO/IEC 10731 , which structures communication systems into

seven layers. When mapped on this model, the services used by a diagnostic tester (client) and an

Electronic Control Unit (ECU, server) are structured into the following layers:
— Application layer (layer 7) specified in ISO 14229-1 and ISO 14229-x;
— Presentation layer (layer 6) specified in ISO 14229-1 and ISO 14229-x;
— Session layer services (layer 5) specified in ISO 14229-2 and ISO 14229-x.
Figure 1 illustrates the ISO 14229-2 documents reference according to OSI model.
Figure 1 — ISO 14229-2 documents reference according to OSI model
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DRAFT INTERNATIONAL STANDARD ISO/DIS 14229-2:2021(E)
Road vehicles — Unified diagnostic services (UDS) —
Part 2:
Session layer services
1 Scope

This document specifies common session layer services and requirements to provide independence

between unified diagnostic services (ISO 14229-1) and all transport protocols and network layer

services (e.g. ISO 13400-2 DoIP, ISO 15765-2 DoCAN, ISO 10681-2 Communication on FlexRay,

ISO 14230-2 DoK-Line, and ISO 20794-3 CXPI).

This document specifies a common service primitive interface between OSI layer 5 (Session) and layer 4

(Transport) via so-called service request/confirmation/indication primitives.

Annex B (informative) describes vehicle diagnostic OSI layer architecture examples.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 14229-1, Road vehicles — Unified diagnostic services (UDS) — Part 1: Application layer

3 Terms and definitions
[1]

For the purposes of this document, the terms and definitions given in ISO 14229-1, ISO/IEC 7498-1 ,

and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
gateway
networking device that transfers the PDU on different OSI layers

EXAMPLE A network device that enables communication between control module networks that uses

different communication protocols, different communication rates, etc. That includes, but is not limited to,

gateway functionalities like bridge, switch, router or application layer routing.

3.2
router
networking device that transfers the PDU on OSI layers 3 and 4
3.3
switch
networking device that transfers the PDU on OSI layer 2
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ISO/DIS 14229-2:2021(E)
4 Symbols and abbreviated terms
4.1 Symbols
— empty cell/undefined
4.2 Abbreviated terms
Diag diagnostics
DiagNormAddr diagnostic message with normal addressing
DiagNormFixAddr diagnostic message with normal fixed addressing
DiagExtAddr diagnostic message with extended addressing
ECU electronic control unit
OSI open systems interconnection
RDiag remote diagnostics
RDiagMixAddr remote diagnostic message with mixed addressing
S_AE session layer address extension
S_Data session layer data transfer service name
S_Length session layer length of data
S_Mtype session layer message type
S_PDU session layer protocol data unit
S_SA session layer source address
S_TA session layer target address
S_TAtype session layer target address type
SecureDiag secure diagnostics
SecureRDiag secure remote diagnostics
SI service identifier
SOM start of message
SPP service primitive parameter
5 Conventions
[2]

This document is based on OSI service conventions as specified in ISO/IEC 10731 .

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ISO/DIS 14229-2:2021(E)
6 Session layer services
6.1 Service interface

The service interface defines a set of services that are needed to access the functions offered by the

session layer, i.e. transmission/reception of data and setting of protocol parameters.

The session layer services have the same general structure. The service primitives define how a service

user (e.g. diagnostic application) cooperates with a service provider (e.g. session layer). To define the

services, three types of service primitives are specified:

— a service request primitive S_Data.request, used by the higher application layer to pass control

information or data required to be transmitted to the session layer (i.e. the service provider is being

requested by the service user to process control information or to transmit data);

— a service indication primitive S_Data.indication, used by the session layer to pass status information

and received data to the higher application layer (i.e. the service user is being informed by the

service provider about an internal event of the session layer or the service request of a peer protocol

layer entity service user);

— a service confirmation primitive S_Data.confirm used by the session layer to pass status information

to the application layer (i.e. the service user is being informed by service provider about the result

of a preceding service request of the service user);
6.2 Service interface parameters

The session layer services shall have the same general format. Service primitives shall be written in

the form:
service_name.type (
parameter A,
parameter B,
parameter C,
[parameter X],
...
)
where:
— "service_name" is the name of the service (e.g. S_Data),

— "type" indicates the type of the service primitive (e.g. request, indication, confirm),

— "parameter A, ..." is the S_PDU (Session layer Protocol Data Unit) as a list of values passed by the

service primitive (e.g. addressing information, Data, Length, Result),

— "parameter A, parameter B, parameter C" are mandatory parameters that shall be included in all

service calls, "[parameter X]" is an optional parameter that is included if specific conditions are

fulfilled.
6.3 Service interface primitives

Figure 2 shows the session layer service primitives of a message transmission with a T_Data.ind

reception at the session layer of the receiver side from the lower OSI layer.
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ISO/DIS 14229-2:2021(E)
Figure 2 — Session layer service primitives – T_Data.ind message reception

Figure 3 shows the session layer service primitives of a message transmission with a T_DataSOM.ind

reception at the beginning of the message and a T_Data.ind reception at the end of the message at the

session layer of the receiver side from the lower OSI layer.
for a multiple frame message.
Key
1 StartOfMessage transport layer data indication e.g. ISO 15765-2

Figure 3 — Session layer service primitives – T_DataSOM.ind and T_Data.ind reception

The following communication scenarios shall be distinguished:
a) physical communication during
1) default session, and
2) non-default session — session handling required.
b) functional communication during
3) default session, and
4) non-default session — session handling required.
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ISO/DIS 14229-2:2021(E)
7 Service interface (SI) definition from application layer to session layer
7.1 SI — S_Data.req, S_Data.ind, and S_Data.conf service interface

The service interface defines the service and parameter mapping from the application layer to the

session layer.
Figure 4 shows the S_Data.req, S_Data.ind, and S_Data.conf service interface.
Key
1 service access point
2 read back from N-layer service provider
Figure 4 — S_Data.req and S_Data.ind service interface

7.2 SI — S_Data.req, S_Data.ind, and S_Data.conf service interface parameter mapping

This requirement specifies the application service interface and parameter mapping between session

layer and the lower OSI layers.

REQ 0.1 SI — S_Data.req, S_Data.ind, and S_Data.conf service interface parameter mapping

The S_Data.req, S_Data.ind, and S_Data.conf service interface parameter mapping shall be implemented

as specified in Table 1.
Table 1 — S_Data.req and S_Data.ind service interface parameter mapping
Application layer Session layer A_Data.req and A_Data.ind parameter validity
(service user) (service provider) .req .ind .conf
a a a
A_Mtype S_Mtype X X X
a a a
A_TAtype S_TAtype X X X
a a a
A_TA S_TA X X X
a a a
A_SA S_SA X X X
supported = “X”;
not supported = “—”.
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ISO/DIS 14229-2:2021(E)
Table 1 (continued)
Application layer Session layer A_Data.req and A_Data.ind parameter validity
(service user) (service provider) .req .ind .conf
a a b
A_Length S_Length X X —
a a a
A_AE S_AE X X X
a a b
A_Data S_Data X X —
b b a
A_Result S_Result — — X
supported = “X”;
not supported = “—”.
7.3 SI — S_PDU mapping onto T_PDU and vice versa for message transmission

The parameters of the session layer protocol data unit defined to request the transmission of a

diagnostic service request/response are mapped onto the parameters of the transport layer protocol

data unit for the transmission of a message in the client/server. Annex A (informative) specifies the

T_PDU interface and shall be followed.

The parameters of the transport layer protocol data unit defined for the reception of a message are

mapped as follows onto the parameters of the session layer protocol data unit for the confirmation/

indication of the reception of a diagnostic response/request.

The transport layer confirmation of the successful transmission of the message (T_Data.conf) is

forwarded to the application, because it is needed in the application for starting those actions, which

shall be executed immediately after the transmission of the request/response message (e.g. ECUReset,

bit rate change, etc.).

The transport/network layer indication for the reception of a StartOfMessage T_PDU (T_DataSOM.ind)

e.g. ISO 15765-2 is not forwarded to the application layer, because it is only used within the session

layer to perform the session layer timing (see Clause 9). Therefore, no mapping of the T_DataSOM.ind

T_PDU onto an S_PDU is defined.

Table 2 defines the mapping of session layer S_PDU onto transport layer T_PDU and vice versa.

Table 2 — Mapping of session layer S_PDU onto transport layer T_PDU and vice versa

S_PDU parameter Description T_PDU parameter Description
(Session layer Protocol (Transport layer Pro-
Data Unit) tocol Data Unit)
S_Mtype Session layer message type T_Ptype Transport layer packet type
S_SA Session layer source address T_SA Transport layer source ad-
dress
S_TA Session layer target address T_TA Transport layer target ad-
dress
S_TAtype Session layer target ad- T_TAtype Transport layer target ad-
dress type dress type
a a
S_AE Session layer address T_AE Transport layer address
extension extension

S_Data[1] – S_Data[n] Session layer data T_Data[1] – T_Data[n] Transport layer data

S_Length Session layer data Length T_Length Transport/Network layer
Data Length

If Mtype = diagnostics/secure diagnostics, then the address information shall consist of the parameters SA, TA,

and TAtype.

If Mtype = remote diagnostics/secure remote diagnostics, then the address information shall consist of the parameters SA,

TA, TAtype, and AE.
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ISO/DIS 14229-2:2021(E)
Table 2 (continued)
S_PDU parameter Description T_PDU parameter Description
(Session layer Protocol (Transport layer Pro-
Data Unit) tocol Data Unit)
S_Result Session layer result T_Result Transport layer result

If Mtype = diagnostics/secure diagnostics, then the address information shall consist of the parameters SA, TA,

and TAtype.

If Mtype = remote diagnostics/secure remote diagnostics, then the address information shall consist of the parameters SA,

TA, TAtype, and AE.
7.4 SI — S_Data.req

The service primitive requests transmission of S_Data with S_Length number of bytes from the sender

to the receiver peer entities identified by the address information in S_SA, S_TA, S_TAtype, and S_AE.

If the S_Data.req service is called; the session layer signals the completion (or failure) of the message

transmission to the service user by means of the issuing of an S_Data.conf service call.

S_Data.req (
S_Mtype,
S_SA,
S_TA,
S_TAtype,
[S_AE],
S_Data [Data#1, Data#2, …, Data#n ],
S_Length
)
7.5 SI — S_Data.conf

The S_Data.conf service is issued by the session layer. The service primitive confirms the completion

of an S_Data.req service identified by the address information in S_SA, S_TA, S_TAtype, and S_AE. The

parameter S_Result provides the status of the service request.
S_Data.conf (
S_SA,
S_TA,
S_TAtype,
[S_AE],
S_Result
)
7.6 SI — S_Data.ind

The S_Data.indication service is issued by the session layer. The service primitive shall indicate S_Result

events and delivers S_Data with S_Length bytes received from a peer protocol entity identified by the

address information in S_SA, S_TA, S_TAtype to the adjacent upper layer. The parameters S_Data and

S_Length shall only be valid if S_Result equals S_OK.
S_Data.ind (
S_Mtype,
S_SA
S_TA,
S_TAtype,
[S_AE],
S_Data [Data#1, Data#2, …, Data#n ],
S_Length,
S_Result
)
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ISO/DIS 14229-2:2021(E)
8 Service primitive parameters (SPP)
8.1 SPP – General

Clause 8 specifies the service primitive parameters and data types, which are used by the application

layer services.
8.2 SPP – Data type definitions
REQ 0.2 SPP – Data type definitions
The data types shall be in accordance to:
— Enum = 8-bit enumeration
— Unsigned Byte = 8-bit unsigned numeric value
— Unsigned Word = 16-bit unsigned numeric value
— Unsigned Long = 32-bit unsigned numeric value
— Byte Array = sequence of 8-bit aligned data
— Bit String = 8-bit binary coded
8.3 SPP – S_Mtype, session layer message type

The parameter Mtype is used to identify the type and range of address information parameters included

in a service call. This document specifies a range of two values for this parameter.

REQ 0.3 SPP – S_Mtype, session layer message type
The S_Mtype parameter
...