ETSI TS 129 523 V15.2.0 (2019-10)

5G; 5G System; Policy Control Event Exposure Service; Stage 3 (3GPP TS 29.523 version 15.2.0 Release 15)

RTS/TSGC-0329523vf20

General Information

• Status: Published
• Publication Date: 23-Oct-2019
• Technical Committee: 3GPP CT 3 - Interworking with external networks (formely CN3)
• Current Stage: 12 - Completion
• Completion Date: 24-Oct-2019

Standards Content (Sample)

TECHNICAL SPECIFICATION
5G;
5G System;
Policy Control Event Exposure Service;
Stage 3
(3GPP TS 29.523 version 15.2.0 Release 15)


3GPP TS 29.523 version 15.2.0 Release 15 1 ETSI TS 129 523 V15.2.0 (2019-10)

Reference
RTS/TSGC-0329523vf20
Keywords
5G
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI
deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© ETSI 2019.
All rights reserved.
DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.

3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and
of the oneM2M Partners. ®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 2 ETSI TS 129 523 V15.2.0 (2019-10)
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
3GPP TS 29.523 version 15.2.0 Release 15 3 ETSI TS 129 523 V15.2.0 (2019-10)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions, symbols and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 Npcf_EventExposure Service . 7
4.1 Service Description . 7
4.1.1 Overview . 7
4.1.2 Service Architecture . 8
4.1.3 Network Functions . 9
4.1.3.1 Policy Control Function (PCF) . 9
4.1.3.2 NF Service Consumers . 9
4.2 Service Operations . 9
4.2.1 Introduction. 9
4.2.2 Npcf_EventExposure_Subscribe service operation . 9
4.2.2.1 General . 9
4.2.2.2 Creating a new subscription . 10
4.2.2.3 Modifying an existing subscription . 11
4.2.3 Npcf_EventExposure_UnSubscribe service operation . 12
4.2.3.1 General . 12
4.2.3.2 Unsubscription from event notifications . 12
4.2.4 Npcf_EventExposure_Notify service operation . 13
4.2.4.1 General . 13
4.2.4.2 Notification about subscribed events . 13
5 Npcf_EventExposure Service API . 14
5.1 Introduction . 14
5.2 Usage of HTTP . 15
5.2.1 General . 15
5.2.2 HTTP standard headers . 15
5.2.2.1 General . 15
5.2.2.2 Content type . 15
5.2.3 HTTP custom headers . 15
5.2.3.1 General . 15
5.3 Resources . 15
5.3.1 Resource Structure . 15
5.3.2 Resource: Policy Control Events Subscriptions (Collection) . 16
5.3.2.1 Description . 16
5.3.2.2 Resource definition . 16
5.3.2.3 Resource Standard Methods . 16
5.3.2.3.1 POST . 16
5.3.2.4 Resource Custom Operations . 17
5.3.3 Resource: Individual Policy Control Events Subscription (Document) . 17
5.3.3.1 Description . 17
5.3.3.2 Resource definition . 17
5.3.3.3 Resource Standard Methods . 17
5.3.3.3.1 GET . 17
5.3.3.3.2 PUT . 18
5.3.3.3.3 DELETE . 18
5.3.3.4 Resource Custom Operations . 19
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 4 ETSI TS 129 523 V15.2.0 (2019-10)
5.4 Custom Operations without associated resources. 19
5.5 Notifications . 19
5.5.1 General . 19
5.5.2 Policy Control Event Notification . 19
5.5.2.1 Description . 19
5.5.2.2 Target URI . 19
5.5.2.3 Standard Methods . 19
5.5.2.3.1 POST . 19
5.6 Data Model . 20
5.6.1 General . 20
5.6.2 Structured data types . 21
5.6.2.1 Introduction . 21
5.6.2.2 Type PcEventExposureSubsc . 22
5.6.2.3 Type PcEventExposureNotif . 22
5.6.2.4 Type ReportingInformation. 23
5.6.2.5 Type ServiceIdentification . 23
5.6.2.6 Type EthernetFlowInfo . 24
5.6.2.7 Type IpFlowInfo . 24
5.6.2.8 Type PcEventNotification . 24
5.6.2.9 Type PduSessionInformation . 25
5.6.3 Simple data types and enumerations . 25
5.6.3.1 Introduction . 25
5.6.3.2 Simple data types . 25
5.6.3.3 Enumeration: PcEvent . 25
5.7 Error handling . 25
5.7.1 General . 25
5.7.2 Protocol Errors . 26
5.7.3 Application Errors . 26
5.8 Feature negotiation . 26
5.9 Security . 26
Annex A (normative): OpenAPI specification . 27
A.1 General . 27
A.2 Npcf_EventExposure API . 27
Annex B (informative): Change history . 33
History . 34

ETSI
3GPP TS 29.523 version 15.2.0 Release 15 5 ETSI TS 129 523 V15.2.0 (2019-10)
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.
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 6 ETSI TS 129 523 V15.2.0 (2019-10)
1 Scope
The present document specifies the stage 3 protocol and data model for the Policy Control Event Exposure Service of
the 5G System. It provides stage 3 protocol definitions, message flows and specifies the API for the Npcf Event
Exposure service.
The 5G System stage 2 architecture and the procedures are specified in 3GPP TS 23.501 [2], 3GPP TS 23.502 [3] and
3GPP TS 23.503 [4].
The 5G System stage 3 call flows are provided in 3GPP TS 29.513 [8].
The Technical Realization of the Service Based Architecture and the Principles and Guidelines for Services Definition
are specified in 3GPP TS 29.500 [5] and 3GPP TS 29.501 [6].
The Policy Control Event Exposure Service is provided by the Policy Control Function (PCF). This service exposes
policy control events observed at the PCF.
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 23.503: "Policy and Charging Control Framework for the 5G System; Stage 2".
[5] 3GPP TS 29.500: "5G System; Technical Realization of Service Based Architecture; Stage 3".
[6] 3GPP TS 29.501: "5G System; Principles and Guidelines for Services Definition; Stage 3".
[7] OpenAPI: "OpenAPI 3.0.0 Specification", https://github.com/OAI/OpenAPI-
Specification/blob/master/versions/3.0.0.md.
[8] 3GPP TS 29.513: "5G System; Policy and Charging Control signalling flows and QoS parameter
mapping; Stage 3".
[9] 3GPP TS 29.512: "5G System; Session Management Policy Control Service; Stage 3".
[10] 3GPP TS 29.507: "5G System; Access and Mobility Policy Control Service; Stage 3".
[11] 3GPP TS 29.525: "5G System; UE Policy Control Service; Stage 3".
[12] 3GPP TS 29.514: "5G System; Policy Authorization Service; Stage 3".
[13] 3GPP TS 29.214: "Policy and Charging Control over Rx reference point".
[14] 3GPP TS 29.571: "5G System; Common Data Types for Service Based Interfaces; Stage 3".
[15] 3GPP TS 29.508: "5G System; Session Management Event Exposure Service; Stage 3".
[16] IETF RFC 7540: "Hypertext Transfer Protocol Version 2 (HTTP/2)".
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 7 ETSI TS 129 523 V15.2.0 (2019-10)
[17] IETF RFC 8259: "The JavaScript Object Notation (JSON) Data Interchange Format".
[18] IETF RFC 7807: "Problem Details for HTTP APIs".
[19] 3GPP TS 33.501: "Security architecture and procedures for 5G system".
[20] IETF RFC 6749: "The OAuth 2.0 Authorization Framework".
[21] 3GPP TS 29.510: "5G System; Network Function Repository Services; Stage 3".
[22] 3GPP TR 21.900: "Technical Specification Group working methods".
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].
example: text used to clarify abstract rules by applying them literally.
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].
AF Application Function
API Application Programming Interface
DNN Data Network Name
ePDG evolved Packet Data Gateway
GPSI Generic Public Subscription Identifier
HTTP Hypertext Transfer Protocol
NEF Network Exposure Function
NF Network Function
NRF Network Repository Function
PCF Policy Control Function
RFSP RAT Frequency Selection Priority
S-NSSAI Single Network Slice Selection Assistance Information
SUPI Subscription Permanent Identifier
URSP UE Route Selection Policy
4 Npcf_EventExposure Service
4.1 Service Description
4.1.1 Overview
The Policy Event Exposure Service, as defined in 3GPP TS 23.502 [3] and 3GPP TS 23.503 [4], is provided by the
Policy Control Function (PCF).
This service:
- allows NF service consumers to subscribe, modify and unsubscribe for policy control events; and
- notifies NF service consumers with a corresponding subscription about observed events on the PCF.
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 8 ETSI TS 129 523 V15.2.0 (2019-10)
The types of observed events include:
- PLMN identifier notification; and
- Access type change.
The target of the event reporting may include a group of UE(s) or any UE (i.e. all UEs). When the event occurs, to
which the NF service consumer has subscribed to, the PCF reports the requested information to the NF service
consumer based on the event reporting information definition requested by the NF service consumer (see
3GPP TS 23.502 [3], subclause 4.15.1).
4.1.2 Service Architecture
The 5G System Architecture is defined in 3GPP TS 23.501 [2]. The Policy and Charging related 5G architecture and
signalling flows are also described in 3GPP TS 29.513 [8].
The Policy Event Exposure Service (Npcf_EventExposure) is part of the Npcf service-based interface exhibited by the
Policy Control Function (PCF).
The only known NF service consumer of the Npcf_EventExposure service is the Network Exposure Function (NEF).
The Npcf_EventExposure service is provided by the PCF and consumed by the NEF, as shown in figure 4.1.2-1 for the
SBI representation model and in figure 4.1.2-2 for reference point representation model.
PCF
Npcf
Npcf_EventExposure
NEF
Figure 4.1.2-1: Npcf_EventExposure service Architecture, SBI representation
PC F
N30
NEF
Figure 4.1.2-2: Npcf_EventExposure service Architecture, reference point representation
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 9 ETSI TS 129 523 V15.2.0 (2019-10)
4.1.3 Network Functions
4.1.3.1 Policy Control Function (PCF)
The PCF (Policy Control Function) is a functional element that encompasses policy control decision and flow based
charging control functionalities as defined in 3GPP TS 29.512 [9], access and mobility policy decisions for the control
of the UE Service Area Restrictions and RAT/RFSP control as defined in 3GPP TS 29.507 [10] and UE Policy
decisions for the control of Access network discovery and selection policy and UE Route Selection Policy (URSP) as
defined in 3GPP TS 29.525 [11].
The policy control decision and flow based charging control functionalities enable the PCF to provide network control
regarding the service data flow detection, gating, QoS and flow based charging (except credit management) towards the
SMF/UPF. The PCF offers these capabilities to the NF service consumers (e.g. the AF and NEF) as defined in
3GPP TS 29.514 [12] and 3GPP TS 29.214 [13].
The Policy Event Exposure Service enables the PCF to report policy control events observed in one or more PCF
services to NF service consumers.
4.1.3.2 NF Service Consumers
The Network Exposure Function (NEF) is a functional element that supports the following functionalities:
- The NEF securely exposes network capabilities and events provided by 3GPP NFs to AF.
- The NEF provides a means for the AF to securely provide information to 3GPP network and can authenticate,
authorize and assist in throttling the AF.
- The NEF translates the information received from the AF to the one sent to internal 3GPP NFs, and vice versa.
- The NEF supports exposing information (collected from other 3GPP NFs) to the AF.
4.2 Service Operations
4.2.1 Introduction
Service operations defined for the Npcf_EventExposure Service are shown in table 4.2.1-1.
Table 4.2.1-1: Npcf_EventExposure Service Operations
Service Operation Name Description Initiated by
Npcf_EventExposure_Subscribe This service operation is used by an NF service NF service
consumer to subscribe for event notifications on consumer (NEF)
a specified policy control event for a group of
UE(s) or any UE, or to modify a subscription.
Npcf_EventExposure_Unsubscribe This service operation is used by an NF service NF service
consumer to unsubscribe from event consumer (NEF)
notifications.
Npcf_EventExposure_Notify This service operation is used by the PCF to PCF
report UE related policy control event(s) to the
NF service consumer which has subscribed to
the event report service.
4.2.2 Npcf_EventExposure_Subscribe service operation
4.2.2.1 General
This service operation is used by an NF service consumer to subscribe for policy events notifications on a specified
context for a group of UE(s) or any UE, or to modify an existing subscription.
The following are the types of events for which a subscription can be made:
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 10 ETSI TS 129 523 V15.2.0 (2019-10)
- PLMN identifier notification; and
- Change of Access Type.
The following procedures using the Npcf_EventExposure_Subscribe service operation are supported:
- creating a new subscription;
- modifying an existing subscription.
4.2.2.2 Creating a new subscription
Figure 4.2.2.2-1 illustrates the creation of a subscription.
NF service
PCF
consumer
1. POST …/subscriptions/
2. "201 Created"
Figure 4.2.2.2-1: Creation of a subscription
To subscribe to event notifications, the NF service consumer shall send an HTTP POST request with: "{apiRoot}/npcf-
eventexposure/v1/subscriptions/" as request URI as shown in figure 4.2.2.2-1, step 1, and the "PcEventExposureSubsc"
data structure as request body.
The "PcEventExposureSubsc" data structure shall include:
- identification of the policy events to subscribe as "eventSubs" attribute;
- indication of the UEs to which the subscription applies via:
a) identification of a group of UE(s) via a "groupId" attribute; or
b) identification of any UE by ommitting the "groupId" attribute.
- a URI where to receive the requested notifications as "notifUri" attribute; and
- a Notification Correlation Identifier assigned by the NF service consumer for the requested notifications as
"notifId" attribute.
The "PcEventExposureSubsc" data structure may include:
- description of the event reporting information as "eventsRepInfo", which may include:
a) event notification method (periodic, one time, on event detection) as "notifMethod" attribute;
b) Maximum Number of Reports as "maxReportNbr" attribute;
c) Monitoring Duration as "monDur" attribute;
d) repetition period for periodic reporting as "repPeriod" attribute; and/or
e) immediate reporting indication as "immRep" attribute.
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 11 ETSI TS 129 523 V15.2.0 (2019-10)
- if the supported feature "ExtendedSessionInformation" is supported, to filter the AF sessions for which the
policy event report shall occur, the identification of the services one or more AF sessions may belong to as
"filterServices" attribute, which may include per service identification:
a) a list of ethernet flows in the "servEthFlows" attribute; or
b) a list of IP flows in the "servIpFlows" attribute; and/or
c) an AF application identifier in the "afAppId" attribute.
- to filter the DNNs for which the policy event report shall occur, the identification of the DNNs in the
"filterDnns" attribute; and
- to filter the S-NSSAIs for which the policy event report shall occur, the identification of the S-NSSAIs in the
"filterSnssais" attribute.
If the PCF cannot successfully fulfil the received HTTP POST request due to the internal PCF error or due to the error
in the HTTP POST request, the PCF shall send the HTTP error response as specified in subclause 5.7.
Upon successful reception of the HTTP POST request with "{apiRoot}/npcf-eventexposure/v1/subscriptions/" as
request URI and "PcEventExposureSubsc " data structure as request body, the PCF shall create a new "Individual Policy
Events Subscription" resource, shall store the subscription and shall send a HTTP "201 Created" response as shown in
figure 4.2.2.2-1, step 2. The PCF shall include in the "201 Created" response:
- a Location header field; and
- an "PcEventExposureSubsc " data type in the payload body.
The Location header field shall contain the URI of the created individual application session context resource i.e.
"{apiRoot}/ npcf-eventexposure/v1/subscriptions/{subscriptionId}".
The "PcEventExposureSubsc " data type payload body shall contain the representation of the created "Individual Policy
Events Subscription".
When the "monDur" attribute is included in the response, it represents a server selected expiry time that is equal or less
than a possible expiry time in the request.
When the "immRep" attribute is included in the subscription and the subscribed policy control events are available, the
PCF shall immediately notify the NF service consumer using the Npcf_EventExposure_Notify service operation, as
described in subclause 4.2.4.2.
4.2.2.3 Modifying an existing subscription
Figure 4.2.2.3-1 illustrates the modification of an existing subscription.
NF service
PCF
consumer
1. PUT …/subscriptions/{subscriptionId}
2. "200 OK"
Figure 4.2.2.3-1: Modification of an existing subscription
To modify an existing subscription to event notifications, the NF service consumer shall send an HTTP PUT request
with: "{apiRoot}/npcf-eventexposure/v1/subscriptions/{subscriptionId}" as request URI, as shown in figure 4.2.2.3-1,
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 12 ETSI TS 129 523 V15.2.0 (2019-10)
step 1, where "{subscriptionId}" is the subscription correlation ID of the existing subscription. The
"PcEventExposureSubsc " data structure is included as request body as described in subclause 4.2.2.2.
NOTE 1: An alternate NF service consumer than the one that requested the generation of the subscription resource
can send the PUT.
NOTE 2: The "notifUri" attribute within the PcEventExposureSubsc data structure can be modified to request that
subsequent notifications are sent to a new NF service consumer.
If the PCF cannot successfully fulfil the received HTTP PUT request due to the internal PCF error or due to the error in
the HTTP PUT request, the PCF shall send the HTTP error response as specified in subclause 5.7.
Upon successful reception of an HTTP PUT request with: "{apiRoot}/npcf-
eventexposure/v1/subscriptions/{subscriptionId}" as request URI and "PcEventExposureSubsc " data structure as
request body, the PCF shall store the subscription and shall send a HTTP "200 OK" response as shown in figure 4.2.2.3-
1, step 2, with the "PcEventExposureSubsc " data structure as response body.
The "PcEventExposureSubsc " data structure payload body shall contain the representation of the modified "Individual
Policy Events Subscription".
When the "monDur" attribute is included in the response, it represents a NF service producer selected expiry time that is
equal or less than a possible expiry time received in the request.
When the "immRep" attribute is included in the updated subscription and the subscribed policy control events are
available, the PCF shall immediately notify the NF service consumer using the Npcf_EventExposure_Notify service
operation, as described in subclause 4.2.4.2.
4.2.3 Npcf_EventExposure_UnSubscribe service operation
4.2.3.1 General
This service operation is used by an NF service consumer to unsubscribe from event notifications.
The following procedure using the Npcf_EventExposure_UnSubscribe service operation is supported:
- unsubscription from event notifications.
4.2.3.2 Unsubscription from event notifications
Figure 4.2.3.2-1 illustrates the unsubscription from event notifications.
NF service
PCF
consumer
1. DELETE …/subscriptions/{subscriptionId}
2. "204 No Content"
Figure 4.2.3.2-1: Unsubscription from event notifications
To unsubscribe from event notifications, the NF service consumer shall send an HTTP DELETE request with:
"{apiRoot}/npcf-eventexposure/v1/subscriptions/{subscriptionId}" as request URI, as shown in figure 4.2.3.2-1, step 1,
where "{subscriptionId}" is the subscription correlation identifier of the existing resource subscription that is to be
deleted.
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 13 ETSI TS 129 523 V15.2.0 (2019-10)
If the PCF cannot successfully fulfil the received HTTP DELETE request due to the internal PCF error or due to the
error in the HTTP DELETE request, the PCF shall send the HTTP error response as specified in subclause 5.7.
Upon successful reception of the HTTP DELETE request with: "{apiRoot}/npcf-
eventexposure/v1/subscriptions/{subscriptionId}" as request URI, the PCF shall remove the corresponding subscription
and shall send an HTTP "204 No Content" response as shown in figure 4.2.3.2-1, step 2.
4.2.4 Npcf_EventExposure_Notify service operation
4.2.4.1 General
The Npcf_EventExposure_Notify service operation enables the PCF to notify to the NF service consumers that the
previously subscribed policy control event occurred.
The following procedure using the Npcf_EventExposure_Notify service operation is supported:
- notification about subscribed events.
4.2.4.2 Notification about subscribed events
Figure 4.2.4.2-1 illustrates the notification about subscribed events.
NF service
PCF
consumer
1. POST {notifUri}
2. "204 No Content"
Figure 4.2.4.2-1: Notification about subscribed events
If the PCF observes policy control related event(s) for which an NF service consumer has subscribed to, the PCF shall
send an HTTP POST request as shown in figure 4.2.4.2-1, step 1, with the "{notifUri}" as request URI with the value
previously provided by the NF service consumer within the corresponding subscription, and the
"PcEventExposureNotif" data structure.
The "PcEventExposureNotif" data structure shall include:
- Notification correlation ID provided by the NF service consumer during the subscription as "notifId" attribute;
and
- information about the observed event(s) within the "eventNotifs" attribute that shall contain for each observed
event an "PcEventNotification" data structure that shall include:
1. the Policy Control event as "event" attribute;
2. for an access type change:
a) new access type as "accType" attribute;
b) the new RAT type as "ratType" attribute, if applicable for the notified access type; and
c) for EPC inteworking scenarios, the ePDG address as "anGwAddr" attribute, if applicable for the notified
access type;
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 14 ETSI TS 129 523 V15.2.0 (2019-10)
3. for a PLMN change:
a) new PLMN as "plmnId" attribute;
4. the identity of the affected UE in the "supi" attribute and, if available, in the "gpsi" attribute;
5. the time at which the event was observed encoded as "timeStamp" attribute;
6. if available, and if the feature "ExtendedSessionInformation" is supported, information about the PDU
session involved in the reported event in the "pduSessInfo" attribute, that shall include:
a) the S-NSSAI of the PDU session in the "snssai" attribute;
b) the DNN of the PDU session in the "dnn" attribute; and
c) the IPv4 address in the "ueIpv4" attribute and/or the IPv6 prefix in the "ueIpv6" attribute, or the Ethernet
MAC address in the "ueMac" attribute; and
if the IPv4 address is included in the "ueIpv4" attribute, may include the IP domain in the "ipDomain"
attribute;
7. if available, and if the feature "ExtendedSessionInformation" is supported, information about the services
involved in the reported event in the indicated PDU session in the "repServices" attribute, which may include
per identified service:
a) a list of Ethernet flows in the "servEthFlows" attribute which contains an impacted Ethernet flow number
within the "flowNumber" attribute in each EthernetFlowInfo data structure; or
b) a list of IP flows in the "servIpFlows" attribute which contains an impacted IP flow number within the
"flowNumber" attribute in each IpFlowInfo data structure; and/or
c) an AF application identifier in the "afAppId" attribute.
If the NF service consumer cannot successfully fulfil the received HTTP POST request due to the internal error or due
to the error in the HTTP POST request, the NF service consumer shall send the HTTP error response as specified in
subclause 5.7.
Upon successful reception of the HTTP POST request with "{notifUri}" as request URI and a "PcEventExposureNotif"
data structure as request body, the NF service consumer shall send a "204 No Content" HTTP response, as shown in
figure 4.2.4.2-1, step 2, for a successful processing.
5 Npcf_EventExposure Service API
5.1 Introduction
The Npcf_EventExposure Service shall use the Npcf_EventExposure API.
The request URI used in HTTP request from the NF service consumer towards the PCF shall have the structure defined
in subclause 4.4.1 of 3GPP TS 29.501 [6], i.e.:
{apiRoot}/{apiName}/{apiVersion}/{apiSpecificResourceUriPart}
with the following components:
- The {apiRoot} shall be set as described in 3GPP TS 29.501 [6].
- The {apiName} shall be "npcf-eventexposure".
- The {apiVersion} shall be "v1".
- The {apiSpecificResourceUriPart} shall be set as described in subclause 5.3.
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 15 ETSI TS 129 523 V15.2.0 (2019-10)
5.2 Usage of HTTP
5.2.1 General
HTTP/2, IETF RFC 7540 [16], shall be used as specified in subclause 5.2 of 3GPP TS 29.500 [5].
HTTP/2 shall be transported as specified in subclause 5.3 of 3GPP TS 29.500 [5].
The OpenAPI [7] specification of HTTP messages and content bodies for the Npcf_EventExposure is contained in
Annex A.
5.2.2 HTTP standard headers
5.2.2.1 General
See subclause 5.2.2 of 3GPP TS 29.500 [5] for the usage of HTTP standard headers.
5.2.2.2 Content type
JSON, IETF RFC 8259 [17], shall be used as content type of the HTTP bodies specified in the present specification as
specified in subclause 5.4 of 3GPP TS 29.500 [5]. The use of the JSON format shall be signalled by the content type
"application/json".
"Problem Details" JSON object shall be used to indicate additional details of the error in a HTTP response body and
shall be signalled by the content type "application/problem+json", as defined in IETF RFC 7807 [18].
5.2.3 HTTP custom headers
5.2.3.1 General
The mandatory HTTP custom header fields specified in subclause 5.2.3.2 of 3GPP TS 29.500 [5] shall be applicable.
In this Release of the specification, no specific custom headers are defined for the Npcf_EventExposure API.
5.3 Resources
5.3.1 Resource Structure
{apiRoot}/npcf-eventexposure/v1
/subscriptions
/{subscriptionId}
Figure 5.3.1-1: Resource URI structure of the Npcf_EventExposure API
Table 5.3.1-1 provides an overview of the resources and applicable HTTP methods.
ETSI
3GPP TS 29.523 version 15.2.0 Release 15 16 ETSI TS 129 523 V15.2.0 (2019-10)
Table 5.3.1-1: Resources and methods overview
HTTP method or
Resource name Resource URI Description
custom operation
POST Subscription to the notification of
{apiRoot}/
Policy Control policy control events and creation of
npcf-eventexposure/
Events Subscriptions an Individual Policy Control Events
v1/subscriptions
Subscription resource.
GET Reads an Individual Policy Control
Events Subscription resource.
Individual Policy {apiRoot}/ PUT Modifies an Individual Policy Control
Control Events npcf-eventexposure/ Events Subscription.
Subscription v1/subscriptions/{subscriptionId} DELETE Cancels an individual subscription
to notifications of policy control
events.
5.3.2 Resource: Policy Control Events Subscriptions (Collection)
5.3.2.1 Description
The Policy Control Events Subscriptions resource represents all subscriptions of the Npcf_EventExposure ser
...