ETSI TS 129 556 V17.3.0 (2023-04)

5G; Edge Application Server Discovery Services; Stage 3 (3GPP TS 29.556 version 17.3.0 Release 17)

RTS/TSGC-0429556vh30

General Information

• Status: Not Published
• Technical Committee: 3GPP CT 4 - MAP/CAMEL/GTP/BCH/SS/TrFO/IMS/GUP/WLAN (formely CN4)
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 11-Apr-2023

Standards Content (Sample)

TECHNICAL SPECIFICATION
5G;
Edge Application Server Discovery Services;
Stage 3
(3GPP TS 29.556 version 17.3.0 Release 17)


3GPP TS 29.556 version 17.3.0 Release 17 1 ETSI TS 129 556 V17.3.0 (2023-04)

Reference
RTS/TSGC-0429556vh30
Keywords
5G
ETSI
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ETSI
3GPP TS 29.556 version 17.3.0 Release 17 2 ETSI TS 129 556 V17.3.0 (2023-04)
Contents
1 Scope . 7
2 References . 7
3 Definitions, symbols and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 8
4 Overview . 8
4.1 Introduction . 8
5 Services offered by the EASDF . 8
5.1 Introduction . 8
5.2 Neasdf_DNSContext Service . 9
5.2.1 Service Description . 9
5.2.2 Service Operations . 10
5.2.2.1 Introduction . 10
5.2.2.2 Create . 10
5.2.2.2.1 General . 10
5.2.2.3 Update . 10
5.2.2.3.1 General . 10
5.2.2.4 Delete . 12
5.2.2.4.1 General . 12
5.2.2.5 Notify . 12
5.2.2.5.1 General . 12
5.2.3 DNS messages processing by EASDF . 13
5.2.3.1 Introduction . 13
5.2.3.2 DNS message processing model . 13
5.2.3.2.1 DNS Context . 13
5.2.3.2.2 DNS Rule . 13
5.2.3.2.3 Processing flow for incoming DNS messages . 14
5.2.3.2.4 Processing of a One-Time DNS Rule applicable to a specific DNS message earlier buffered
in the EASDF . 15
5.2.3.3 DNS Message Detection Template . 16
5.2.3.3.1 General . 16
5.2.3.3.2 DNS Query MDT . 16
5.2.3.3.3 DNS Response MDT . 16
5.2.3.4 Actions applicable to DNS message . 16
5.2.3.4.1 General . 16
5.2.3.4.2 Event reporting by EASDF. 17
5.2.3.5 Baseline DNS Patterns . 17
5.2.3.5.1 General . 17
5.3 Neasdf_BaselineDNSPattern Service . 18
5.3.1 Service Description . 18
5.3.2 Service Operations . 19
5.3.2.1 Introduction . 19
5.3.2.2 Create . 19
5.3.2.2.1 General . 19
5.3.2.3 Update . 19
5.3.2.3.1 General . 19
5.3.2.4 Delete . 20
5.3.2.4.1 General . 20
6 API Definitions . 21
6.1 Neasdf_DNSContext Service API . 21
6.1.1 Introduction. 21
6.1.2 Usage of HTTP . 21
6.1.2.1 General . 21
6.1.2.2 HTTP standard headers . 22
6.1.2.2.1 General . 22
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6.1.2.2.2 Content type . 22
6.1.2.3 HTTP custom headers . 22
6.1.3 Resources . 22
6.1.3.1 Overview . 22
6.1.3.2 Resource: DNS contexts collection . 23
6.1.3.2.1 Description . 23
6.1.3.2.2 Resource Definition . 23
6.1.3.2.3 Resource Standard Methods . 23
6.1.3.2.4 Resource Custom Operations . 25
6.1.3.3 Resource: Individual DNS context . 25
6.1.3.3.1 Description . 25
6.1.3.3.2 Resource Definition . 25
6.1.3.3.3 Resource Standard Methods . 25
6.1.3.3.4 Resource Custom Operations . 28
6.1.4 Custom Operations without associated resources . 29
6.1.5 Notifications . 29
6.1.5.1 General . 29
6.1.5.2 DNS Context Notify . 29
6.1.5.2.1 Description . 29
6.1.5.2.2 Target URI . 29
6.1.5.2.3 Standard Methods . 29
6.1.6 Data Model . 30
6.1.6.1 General . 30
6.1.6.2 Structured data types . 31
6.1.6.2.1 Introduction . 31
6.1.6.2.2 Type: DnsContextCreateData . 32
6.1.6.2.3 Type: DnsContextCreatedData . 32
6.1.6.2.4 Type: DnsRule . 33
6.1.6.2.5 Type: DnsQueryMdt . 35
6.1.6.2.6 Type: DnsRspMdt . 35
6.1.6.2.7 Type: Ipv4AddressRange . 36
6.1.6.2.8 Type: Ipv6PrefixRange . 36
6.1.6.2.9 Type: Action . 36
6.1.6.2.10 Type: DnsContextNotification . 37
6.1.6.2.11 Type: ForwardingParameters . 37
6.1.6.2.12 Type: EcsOption . 37
6.1.6.2.13 Type: DnsContextEventReport . 37
6.1.6.2.14 Type: DnsQueryReport . 38
6.1.6.2.15 Type: DnsRspReport . 38
6.1.6.2.16 Type: EcsOptionInfo . 38
6.1.6.2.17 Type: DnsServerAddressInfo . 38
6.1.6.2.18 Type: BaselineDnsMdtId . 39
6.1.6.2.19 Type: BaselineDnsAitId . 39
6.1.6.2.20 Type: BaselineDnsQueryMdtInfo . 39
6.1.6.2.21 Type: BaselineDnsRspMdtInfo . 39
6.1.6.3 Simple data types and enumerations . 39
6.1.6.3.1 Introduction . 39
6.1.6.3.2 Simple data types . 39
6.1.6.3.3 Enumeration: ApplyAction. 40
6.1.6.4 Data types describing alternative data types or combinations of data types . 40
6.1.6.5 Binary data . 40
6.1.7 Error Handling . 40
6.1.7.1 General . 40
6.1.7.2 Protocol Errors . 40
6.1.7.3 Application Errors . 40
6.1.8 Feature negotiation . 41
6.1.9 Security . 41
6.2 Neasdf_BaselineDNSPattern Service API . 41
6.2.1 Introduction. 41
6.2.2 Usage of HTTP . 42
6.2.2.1 General . 42
6.2.2.2 HTTP standard headers . 42
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6.2.2.2.1 General . 42
6.2.2.2.2 Content type . 42
6.2.2.3 HTTP custom headers . 42
6.2.3 Resources . 42
6.2.3.1 Overview . 42
6.2.3.2 Resource: Individual Baseline DNS Pattern. 43
6.2.3.2.1 Description . 43
6.2.3.2.2 Resource Definition . 43
6.2.3.2.3 Resource Standard Methods . 44
6.2.3.3.4 Resource Custom Operations . 48
6.2.4 Custom Operations without associated resources . 48
6.2.5 Notifications . 48
6.2.6 Data Model . 48
6.2.6.1 General . 48
6.2.6.2 Structured data types . 49
6.2.6.2.1 Introduction . 49
6.2.6.2.2 Type: BaseDnsPatternCreateData . 49
6.2.6.2.3 Type: BaseDnsPatternCreatedData . 49
6.2.6.2.4 Type: BaselineDnsMdt . 50
6.2.6.2.5 Type: BaselineDnsAit . 50
6.2.6.2.6 Type: VarNfId . 51
6.2.7 Error Handling . 51
6.2.7.1 General . 51
6.2.7.2 Protocol Errors . 51
6.2.7.3 Application Errors . 51
6.2.8 Feature negotiation . 52
6.2.9 Security . 52
Annex A (normative): OpenAPI specification . 53
A.1 General . 53
A.2 Neasdf_DNSContext API. 53
A.3 Neasdf_BaselineDNSPattern API . 62
Annex B (informative): Change history . 67
History . 68

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3GPP TS 29.556 version 17.3.0 Release 17 5 ETSI TS 129 556 V17.3.0 (2023-04)
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
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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.

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1 Scope
The present document specifies the stage 3 protocol and data model for the Neasdf Service Based Interface. It provides
stage 3 protocol definitions and message flows, and specifies the API for each service offered by the EASDF.
The 5G System stage 2 architecture and procedures are specified in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and
3GPP TS 23.548 [14].
The Technical Realization of the Service Based Architecture and the Principles and Guidelines for Services Definition
are specified in 3GPP TS 29.500 [4] and 3GPP TS 29.501 [5].
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 23.501: "System Architecture for the 5G System; Stage 2".
[3] 3GPP TS 23.502: "Procedures for the 5G System; Stage 2".
[4] 3GPP TS 29.500: "5G System; Technical Realization of Service Based Architecture; Stage 3".
[5] 3GPP TS 29.501: "5G System; Principles and Guidelines for Services Definition; Stage 3".
[6] OpenAPI: "OpenAPI Specification Version 3.0.0", https://spec.openapis.org/oas/v3.0.0.
[7] 3GPP TR 21.900: "Technical Specification Group working methods".
[8] 3GPP TS 33.501: "Security architecture and procedures for 5G system".
[9] IETF RFC 6749: "The Oauth 2.0 Authorization Framework".
[10] 3GPP TS 29.510: "5G System; Network Function Repository Services; Stage 3".
[11] IETF RFC 7540: "Hypertext Transfer Protocol Version 2 (HTTP/2)".
[12] IETF RFC 8259: "The JavaScript Object Notation (JSON) Data Interchange Format".
[13] IETF RFC 7807: "Problem Details for HTTP APIs".
[14] 3GPP TS 23.548: "5G System Enhancements for Edge Computing; Stage 2".
[15] IETF RFC 6902: "JavaScript Object Notation (JSON) Patch".
[16] 3GPP TS 29.571: "5G System; Common Data Types for Service Based Interfaces; Stage 3".
[17] Void.
[18] IETF RFC 7871: "Client Subnet in DNS Queries".
[19] 3GPP TS 23.003: "Numbering, addressing and identification".
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3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in 3GPP TR 21.905 [1] and the following
apply. A term defined in the present document takes precedence over the definition of the same term, if any, in 3GPP
TR 21.905 [1].
One-Time DNS Rule: A DNS Rule that applies only once to a specific DNS message earlier buffered in the EASDF
and reported to the SMF (see clause 5.2.3.2.4).

3.2 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [1] and the following apply. An
abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in
3GPP TR 21.905 [1].
BD AIT Baseline DNS Action Information Template
BD MDT Baseline DNS Message Detection Template
EASDF Edge Application Server Discovery Function
ECS EDNS Client Subnet
EDNS Extension mechanisms for DNS
MDT (DNS Query or DNS Response) Message Detection Template
4 Overview
4.1 Introduction
Within the 5GC, the EASDF offers services to the SMF via the Neasdf service based interface (see
3GPP TS 23.548 [14], 3GPP TS 23.501 [2] and 3GPP TS 23.502 [3]).
Figure 4.1-1 provides the reference model (in service based interface representation and in reference point
representation), with focus on the EASDF and the scope of the present specification.
SMF N88 Neasdf EASDF
Figure 4.1-1: Reference model – EASDF
The functionalities supported by the EASDF are listed in clause 5.1.1 of 3GPP TS 23.548 [14].
5 Services offered by the EASDF
5.1 Introduction
The EASDF offers to other NFs the following service:
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Table 5.1-1: NF Service provided by EASDF
Service Name Description Example
Consumer
Neasdf_DNSContext This service enables the consumer to create, update SMF
and delete DNS context in EASDF, or subscribe to
DNS message reporting from EASDF.
Neasdf_BaselineDNSPat This service enables the consumer to create, update SMF
tern and delete Baseline DNS pattern in EASDF.

The Neasdf_DNSContext service and Neasdf_BaselineDNSPattern service are specified in 3GPP TS 23.548 [14].
Table 5.1-2 summarizes the corresponding APIs defined for this specification.
Table 5.1-2: API Descriptions
Service Name Claus Description OpenAPI Specification File apiName Annex
e
Neasdf_DNSContext 6.1 EASDF TS29556_Neasdf_DNSContext.y neasdf- A.2
DNSContext aml dnscontext
Service
Neasdf_BaselineDNSPat6.2 EASDF TS29556_Neasdf_BaselineDNSP neasdf- A.3
tern BaselineDN attern.yaml baselinednspatte
SPattern rn
Service
5.2 Neasdf_DNSContext Service
5.2.1 Service Description
The Neasdf_DNSContext service operates on the DNS contexts. The EASDF is acting as NF Service Producer, while
the SMF is the NF Service Consumer.
Following functionalities are provided by the Neasdf_DNSContext service:
- Create a DNS context in EASDF;
- Update a DNS context in EASDF;
- Delete a DNS context in EASDF;
- Enable the EASDF to report DNS signalling related information to the NF service consumer when receiving
DNS Query or DNS Response.
The Neasdf_DNSContext service supports the following service operations.
Table 5.2.1-1: Service operations supported by the Neasdf_DNSContext service
Service Operations Description Operation Example
Semantics Consumer(s)
Create Create a DNS context in EASDF. Request/Response SMF
Update Update a DNS context in EASDF. Request/Response SMF
Delete Delete a DNS context in EASDF. Request/Response SMF
Notify EASDF reports DNS signalling related Subscribe/Notify SMF
information to the NF service consumer when
receiving DNS Query or DNS Response.

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5.2.2 Service Operations
5.2.2.1 Introduction
See Table 5.2.1-1 for an overview of the service operations supported by the Neasdf_DNSContext service.
5.2.2.2 Create
5.2.2.2.1 General
The Create service operation shall be used to create an individual DNS context for a given PDU Session in the EASDF.
It is used in the following procedures:
- EAS Discovery Procedure with EASDF (see clause 6.2.3.2.2 of 3GPP TS 23.548 [14]).
There shall be only one individual DNS context created in an EASDF per PDU session.
The NF Service Consumer (e.g. SMF) shall create a DNS context by using the HTTP POST method as shown in
Figure 5.2.2.2.1-1.
NF Service
EASDF
Consumer
1. POST ./dns-contexts (DnsContextCreateData)
2a. 201 Created (DnsContextCreatedData)
2b. 4xx/5xx (ProblemDetails) or 3xx

Figure 5.2.2.2.1-1: DNS context creation
1. The NF Service Consumer shall send a POST request to the resource representing the DNS contexts collection
resource of the EASDF. The payload body of the POST request shall contain:
- the UE IP address, S-NSSAI and the DNN of the related PDU session;
- a notification URI for receiving DNS context related event notifications, if notifications are requested;
- one or more DNS rules.
2a. On success, a "201 Created" response shall be returned with the "Location" header containing the URI of the
created resource.
The POST response body shall include:
- the IP address of the EASDF (to be sent by the SMF to the UE).
2b. On failure, or redirection, one of the HTTP status code listed in Table 6.1.3.2.3.1-3 shall be returned.
5.2.2.3 Update
5.2.2.3.1 General
The Update service operation shall be used to update an individual DNS context previously created in the EASDF. The
update operation may apply to the whole DNS context (complete replacement of the data of the existing DNS context
by new data), or it may apply to modify a subset of the parameters of the DNS context.
It is used in the following procedures:
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- EAS Discovery Procedure with EASDF (see clause 6.2.3.2.2 of 3GPP TS 23.548 [14]).
To perform a partial update of the DNS context of a given DNS context Id, the NF Service Consumer shall issue an
HTTP PATCH request, as shown in Figure 5.2.2.3.1-1. This partial update shall be used to add, delete and/or replace
individual parameters of the DNS context.
NF Service
EASDF
Consumer
1. PATCH ./dns-contexts/{dnsContextId} (PatchData)
2a. 204 No Content
2b. 200 OK (PatchResult)
2c. 4xx/5xx (ProblemDetails) or 3xx

Figure 5.2.2.3.1-1: DNS context Partial Update
1. The NF Service Consumer (e.g. SMF) shall send a PATCH request to the resource URI representing the
individual DNS context, identified by the {dnsContextId}. The payload body of the PATCH request shall
contain the list of operations (add/delete/replace) to be applied to parameters in the individual DNS context.
2a. On success, if all the modification instructions in the PATCH request have been implemented, "204 No Content"
shall be returned.
2b. If some of the modification instructions for unknown attribute(s) in the PATCH request have been ignored, the
EASDF shall respond with "200 OK" with the response body containing PatchResult, as specified in
clause 5.2.7.2 of 3GPP TS 29.500 [4].
2c. On failure or redirection, one of the HTTP status code listed in Table 6.1.3.3.3.2-3 shall be returned.
To perform a complete replacement of the data of the DNS context of a given DNS context Id, the NF Service
Consumer shall issue an HTTP PUT request, as shown in Figure 5.2.2.3.1-2:
NF Service
EASDF
Consumer
1. PUT./dns-contexts/{dnsContextId} (DnsContextCreateData)
2a. 204 No Content
2b. 4xx/5xx (ProblemDetails) or 3xx

Figure 5.2.2.3.1-2: DNS context Complete Replacement
1. The NF service consumer (e.g. SMF) shall send a PUT request to the resource URI representing the individual
DNS context, identified by the {dnsContextId}. The payload body of the PUT request shall contain a
representation of the individual DNS context to be completely replaced in the EASDF.
2a. On success, "204 No Content" shall be returned.
2b. On failure or redirection, one of the HTTP status code listed in Table 6.1.3.3.3.3-3 shall be returned.
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5.2.2.4 Delete
5.2.2.4.1 General
The Delete Service operation shall be used by the NF service consumer (e.g. SMF) to delete the individual DNS context
in the EASDF.
NF Service
EASDF
Consumer
1. DELETE ./dns-contexts/{dnsContextId}
2a. 204 No Content
2b. 4xx/5xx (ProblemDetails) or 3xx

Figure 5.2.2.4.1-1: DNS context deletion
1. The NF Service Consumer (e.g. SMF) shall send a DELETE request to delete the individual DNS context
represented by the {dnsContextId}. The request body shall be empty.
2a. On success, "204 No Content" shall be returned. The response body shall be empty.
2b. On failure or redirection, one of the HTTP status code listed in Table 6.1.3.3.3.1-3 shall be returned.
5.2.2.5 Notify
5.2.2.5.1 General
The Notify service operation shall be used to notify the NF Service Consumer (e.g. SMF) about a DNS context related
event, e.g. if a received DNS Query message or DNS response message matches a DNS detection template of an DNS
rule and the associated action requires to report the message to the NF service producer.
It is used in the following procedures:
- EAS Discovery Procedure with EASDF (see clause 6.2.3.2.2 of 3GPP TS 23.548 [14]).
The EASDF shall send an HTTP POST request targeting the DNS context notification URI provided by the NF Service
Consumer in the Create or Update service operation (see clause 5.2.2.2.1). See also Figure 5.2.2.5.1-1.
NF Service
EASDF
Consumer
1. POST {dnsContextnotifUri} (DnsContextNotification)
2a. 204 No Content
2b. 4xx/5xx (ProblemDetails) or 3xx

Figure 5.2.2.5.1-1: DNS Context Notify
1. The EASDF shall send a HTTP POST request to the DNS context notification URI, and the payload body of the
POST request shall contain a DnsContextNotification data structure, with the DNS message report that was
subscribed by the NF Service Consumer.
2a. On success, "204 No Content" shall be returned and the payload body of the POST response shall be empty.
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2b. On failure or redirection, one of the HTTP status code listed in Table 6.1.5.2.3.1-3 shall be returned.
5.2.3 DNS messages processing by EASDF
5.2.3.1 Introduction
This clause specifies how the EASDF shall process DNS messages according to the instructions received from the
SMF.
5.2.3.2 DNS message processing model
5.2.3.2.1 DNS Context
The SMF shall control how the EASDF processes DNS messages received for a particular UE's PDU session by
creating one single DNS context per PDU session including the following information:
- the UE IP address, S-NSSAI and DNN of the PDU session; and
- one or more DNS rules.
There shall be at most one DNS conte
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