ETSI TS 129 501 V15.7.0 (2020-04)

ETSI TS 129 501 V15.7.0 (2020-04)






TECHNICAL SPECIFICATION
5G;
5G System;
Principles and Guidelines for Services Definition;
Stage 3
(3GPP TS 29.501 version 15.7.0 Release 15)

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3GPP TS 29.501 version 15.7.0 Release 15 1 ETSI TS 129 501 V15.7.0 (2020-04)



Reference
RTS/TSGC-0429501vf70
Keywords
5G
ETSI
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3GPP TS 29.501 version 15.7.0 Release 15 2 ETSI TS 129 501 V15.7.0 (2020-04)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Legal Notice
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities. These shall be
interpreted as being references to the corresponding ETSI deliverables.
The cross reference between 3GPP and ETSI identities can be found under http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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3GPP TS 29.501 version 15.7.0 Release 15 3 ETSI TS 129 501 V15.7.0 (2020-04)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 6
1 Scope . 8
2 References . 8
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 9
4 Design Principles for 5GC SBI APIs . 9
4.1 General Principles . 9
4.2 API Design Style and REST Implementation Levels . 10
4.2.1 General . 10
4.2.2 API Design Principles for Query Operation . 10
4.2.3 API Design Principles for Delete Operation . 10
4.3 Version Control . 11
4.3.0 General . 11
4.3.1 Structure of API version numbers . 11
4.3.1.1 API version number format . 11
4.3.1.2 Rules for incrementing field values. 11
4.3.1.3 Visibility of the API version number fields . 14
4.3.1.4 Relation to the Technical Specification version number . 14
4.3.1.5 Discovery of the supported versions . 14
4.3.1.6 Withdrawing API versions . 15
4.4 URI Structure . 15
4.4.1 Resource URI structure . 15
4.4.2 Custom operations URI structure . 16
4.4.3 Callback URI structure . 16
4.5 Resource Representation and Content Format Negotiation . 16
4.5.1 Resource Representation . 16
4.5.2 Content Format Negotiation . 16
4.6 Use of HTTP Methods . 17
4.6.1 Use of Request/Response Communication . 17
4.6.1.1 CRUD . 17
4.6.1.1.1 Creating a Resource . 17
4.6.1.1.1.1 General . 17
4.6.1.1.1.2 Creating a Resource using POST . 17
4.6.1.1.1.3 Creating a Resource using PUT . 18
4.6.1.1.2 Reading a Resource . 19
4.6.1.1.2.1 Reading a Single Resource . 19
4.6.1.1.2.2 Querying a Set of Resources . 19
4.6.1.1.3 Updating a Resource . 20
4.6.1.1.3.1 Usage of HTTP PUT . 20
4.6.1.1.3.2 Usage of HTTP PATCH . 21
4.6.1.1.4 Deleting a Resource . 21
4.6.1.1.5 Query Parameters . 22
4.6.1.1.5.1 General . 22
4.6.1.1.5.2 Complex query expression . 22
4.6.1.2 Custom Operations . 23
4.6.1.3 Use of Asynchronous Operations . 24
4.6.1.4 Special provisions to support the seamless change of AMF as NF service producer. 24
4.6.2 Use of Subscribe/Notify Communication . 25
4.6.2.1 General . 25
4.6.2.2 Management of Subscriptions . 25
ETSI

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3GPP TS 29.501 version 15.7.0 Release 15 4 ETSI TS 129 501 V15.7.0 (2020-04)
4.6.2.2.1 General . 25
4.6.2.2.2 Creation of a Subscription . 25
4.6.2.2.3 Modify a subscription . 26
4.6.2.2.3.1 Modification of a Subscription Using HTTP PUT. 26
4.6.2.2.3.2 Modification of a Subscription Using HTTP PATCH . 27
4.6.2.2.4 Delete a subscription . 28
4.6.2.3 Notifications . 28
4.6.2.4 Special provisions to support the seamless change of AMF as NF service consumer . 29
4.7 HATEOAS . 29
4.7.1 General . 29
4.7.2 3GPP hypermedia format . 29
4.7.3 Advertising legitimate application state transitions . 30
4.7.4 Inferring link relation semantic . 30
4.7.5 Common Relation Types . 30
4.7.5.1 Introduction . 30
4.7.5.2 Registered relation types . 31
4.7.5.3 Extension relation types . 31
4.7.6 Negotiating the support of optional HATEOAS features . 31
4.8 Error Responses . 32
4.9 Transferring multiple resources to a NF Service Consumer . 33
4.9.1 General . 33
4.9.2 Direct Delivery . 33
4.9.3 Direct Delivery with Iterations . 33
4.9.4 Indirect Delivery . 34
4.9.5 Indirect Delivery with HTTP/2 Server Push . 34
4.9.6 Criteria for choosing the transfer method . 36
5 Documenting 5GC SBI APIs . 36
5.1 Naming Conventions . 36
5.1.1 Case Conventions . 36
5.1.2 API Naming Conventions . 38
5.1.3 Conventions for URI Parts . 38
5.1.3.1 Introduction . 38
5.1.3.2 URI Path Segment Naming Conventions . 38
5.1.3.3 URI Query Naming Conventions . 39
5.1.4 Conventions for Names in Data Structures . 39
5.2 API Definition . 39
5.2.1 Resource Structure . 39
5.2.2 Resources and HTTP Methods . 40
5.2.3 Representing RPC as Custom Operations on Resources . 43
5.2.4 Data Models . 44
5.2.4.1 General . 44
5.2.4.2 Structured data types . 45
5.2.4.3 Simple data types and enumerations . 46
5.2.4.4 Binary Data . 46
5.2.4.5 Data types describing alternative data types or combinations of data types . 46
5.2.5 Relation types . 48
5.3 OpenAPI specification files . 48
5.3.1 General . 48
5.3.2 Formatting of OpenAPI specification files . 48
5.3.3 Info. 48
5.3.4 externalDocs . 48
5.3.5 Servers . 49
5.3.6 References to other 3GPP-defined OpenAPI specification files . 49
5.3.7 Server-initiated communication . 50
5.3.8 Describing the body of HTTP PATCH requests . 50
5.3.8.1 General . 50
5.3.8.2 JSON Merge Patch . 51
5.3.8.3 JSON PATCH . 51
5.3.9 Structured data types . 51
5.3.10 Data types describing alternative data types or combinations of data types . 53
5.3.11 Error Responses . 55
ETSI

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3GPP TS 29.501 version 15.7.0 Release 15 5 ETSI TS 129 501 V15.7.0 (2020-04)
5.3.12 Enumerations . 56
5.3.13 Formatting of structured data types in query parameters . 56
5.3.14 Attribute Presence Conditions . 57
5.3.15 Usage of the "tags" field . 59
5.3.16 Security . 59
5.3.17 Reuse of Structured Data Types . 60
6 Requirements for secure API design . 61
6.1 Introduction . 61
6.2 General . 61
6.3 SBA-specific requirements . 61
Annex A (informative): TS Skeleton Template . 63
Annex B (informative): Backward Incompatible Changes . 64
Annex C (Informative): Resource modelling . 65
C.0 General . 65
C.1 Document . 65
C.2 Collection . 65
C.3 Store . 65
C.4 Custom operation . 66
Annex D (informative): Example of an OpenAPI specification file for Patch . 67
Annex E (informative): Change history . 70
History . 73

ETSI

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3GPP TS 29.501 version 15.7.0 Release 15 6 ETSI TS 129 501 V15.7.0 (2020-04)
Foreword
This Technical Specification has been produced by the 3rd Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
In the present document, modal verbs have the following meanings:
shall indicates a mandatory requirement to do something
shall not indicates an interdiction (prohibition) to do something
The constructions "shall" and "shall not" are confined to the context of normative provisions, and do not appear in
Technical Reports.
The constructions "must" and "must not" are not used as substitutes for "shall" and "shall not". Their use is avoided
insofar as possible, and they are not used in a normative context except in a direct citation from an external, referenced,
non-3GPP document, or so as to maintain continuity of style when extending or modifying the provisions of such a
referenced document.
should indicates a recommendation to do something
should not indicates a recommendation not to do something
may indicates permission to do something
need not indicates permission not to do something
The construction "may not" is ambiguous and is not used in normative elements. The unambiguous constructions
"might not" or "shall not" are used instead, depending upon the meaning intended.
can indicates that something is possible
cannot indicates that something is impossible
The constructions "can" and "cannot" are not substitutes for "may" and "need not".
will indicates that something is certain or expected to happen as a result of action taken by an agency
the behaviour of which is outside the scope of the present document
will not indicates that something is certain or expected not to happen as a result of action taken by an
agency the behaviour of which is outside the scope of the present document
might indicates a likelihood that something will happen as a result of action taken by some agency the
behaviour of which is outside the scope of the present document
ETSI

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3GPP TS 29.501 version 15.7.0 Release 15 7 ETSI TS 129 501 V15.7.0 (2020-04)
might not indicates a likelihood that something will not happen as a result of action taken by some agency
the behaviour of which is outside the scope of the present document
In addition:
is (or any other verb in the indicative mood) indicates a statement of fact
is not (or any other negative verb in the indicative mood) indicates a statement of fact
The constructions "is" and "is not" do not indicate requirements.

ETSI

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3GPP TS 29.501 version 15.7.0 Release 15 8 ETSI TS 129 501 V15.7.0 (2020-04)
1 Scope
The present document defines design principles and documentation guidelines for 5GC SBI APIs. These principles and
guidelines should be followed when drafting the 5G System SBI Stage 3 specifications.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 29.500: "5G System; Technical Realization of Service Based Architecture; Stage 3".
[3] IETF RFC 8259: "The JavaScript Object Notation (JSON) Data Interchange Format".
[4] OpenAPI: "OpenAPI 3.0.0 Specification", https://github.com/OAI/OpenAPI-
Specification/blob/master/versions/3.0.0.md.
[5] 3GPP TS 29.571: "5G System; Common Data Types for Service Based Interfaces Stage 3".
[6] IETF RFC 7231: "Hypertext Transfer Protocol
...