ETSI TS 129 521 V15.4.0 (2019-10)

5G; 5G System; Binding Support Management Service; Stage 3 (3GPP TS 29.521 version 15.4.0 Release 15)

RTS/TSGC-0329521vf40

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)

ETSI TS 129 521 V15.4.0 (2019-10)






TECHNICAL SPECIFICATION
5G;
5G System;
Binding Support Management Service;
Stage 3
(3GPP TS 29.521 version 15.4.0 Release 15)

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3GPP TS 29.521 version 15.4.0 Release 15 1 ETSI TS 129 521 V15.4.0 (2019-10)



Reference
RTS/TSGC-0329521vf40
Keywords
5G
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3GPP TS 29.521 version 15.4.0 Release 15 2 ETSI TS 129 521 V15.4.0 (2019-10)
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Legal Notice
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Modal verbs terminology
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3GPP TS 29.521 version 15.4.0 Release 15 3 ETSI TS 129 521 V15.4.0 (2019-10)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 Binding Support Management Service . 7
4.1 Service Description . 7
4.1.1 Overview . 7
4.1.2 Service Architecture . 7
4.1.3 Network Functions . 8
4.1.3.1 Binding Support Function (BSF) . 8
4.1.3.2 NF Service Consumers . 8
4.2 Service Operations . 9
4.2.1 Introduction. 9
4.2.2 Nbsf_Management_Register Service Operation . 9
4.2.2.1 General . 9
4.2.2.2 Register a new PCF Session binding information . 9
4.2.3 Nbsf_Management_Deregister Service Operation . 10
4.2.3.1 General . 10
4.2.3.2 Deregister an individual PCF Session binding information . 11
4.2.4 Nbsf_Management_Discovery Service Operation . 11
4.2.4.1 General . 11
4.2.4.2 Retrieve the PCF Session binding information for a given tuple . 11
5 Nbsf_Management Service API . 12
5.1 Introduction . 12
5.2 Usage of HTTP . 12
5.2.1 General . 12
5.2.2 HTTP standard headers . 12
5.2.2.1 General . 12
5.2.2.2 Content type . 13
5.2.3 HTTP custom headers . 13
5.2.3.1 General . 13
5.3 Resources . 13
5.3.1 Resource Structure . 13
5.3.2 Resource: PCF Session Bindings . 14
5.3.2.1 Description . 14
5.3.2.2 Resource definition . 14
5.3.2.3 Resource Standard Methods . 14
5.3.2.3.1 POST . 14
5.3.2.3.2 GET . 15
5.3.3 Resource: Individual PCF Session Binding . 15
5.4 Custom Operations without associated resources. 16
5.5 Notifications . 16
5.6 Data Model . 16
5.6.1 General . 16
5.6.2 Structured data types . 17
5.6.2.1 Introduction . 17
5.6.2.2 Type PcfBinding . 18
5.6.3 Simple data types and enumerations . 18
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3GPP TS 29.521 version 15.4.0 Release 15 4 ETSI TS 129 521 V15.4.0 (2019-10)
5.6.3.1 Introduction . 18
5.6.3.2 Simple data types . 18
5.7 Error handling . 18
5.8 Feature negotiation . 19
5.9 Security . 19
Annex A (normative): OpenAPI specification . 20
A.1 General . 20
A.2 Nbsf_Management API . 20
Annex C (informative): Change history . 25
History . 26

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3GPP TS 29.521 version 15.4.0 Release 15 5 ETSI TS 129 521 V15.4.0 (2019-10)
Foreword
rd
This Technical Specification has been produced by the 3 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.
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3GPP TS 29.521 version 15.4.0 Release 15 6 ETSI TS 129 521 V15.4.0 (2019-10)
1 Scope
The present specification provides the stage 3 definition of the Binding Support Management Service of the 5G System.
The 5G System Architecture is defined in 3GPP TS 23.501 [2]. The stage 2 definition and related procedures for
Binding Support Management Service is specified in 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 [5].
The Technical Realization of the Service Based Architecture and the Principles and Guidelines for Services Definition
are specified in 3GPP TS 29.500 [6] and 3GPP TS 29.501 [7].
The Binding Support Management Service is provided by the Binding Support Function (BSF).
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 29.513: "5G System; Policy and Charging Control signalling flows and QoS parameter
mapping; Stage 3".
[6] 3GPP TS 29.500: "5G System; Technical Realization of Service Based Architecture; Stage 3".
[7] 3GPP TS 29.501: "5G System; Principles and Guidelines for Services Definition; Stage 3".
[8] IETF RFC 7540: "Hypertext Transfer Protocol Version 2 (HTTP/2)".
[9] IETF RFC 8259: "The JavaScript Object Notation (JSON) Data Interchange Format".
[10] 3GPP TS 29.571: "5G System; Common Data Types for Service Based Interfaces Stage 3".
[11] OpenAPI: "OpenAPI 3.0.0 Specification", https://github.com/OAI/OpenAPI-
Specification/blob/master/versions/3.0.0.md.
[12] 3GPP TS 29.510: "5G System; Network Function Repository Services; Stage 3".
[13] IETF RFC 7807: "Problem Details for HTTP APIs".
[14] 3GPP TS 29.213: " Policy and Charging Control signalling flows and Quality of Service (QoS)
parameter mapping".
[15] 3GPP TS 33.501: "Security architecture and procedures for 5G system".
[16] IETF RFC 6749: "The OAuth 2.0 Authorization Framework".
[17] 3GPP TS 23.527: "5G System; Restoration Procedures".
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[18] 3GPP TR 21.900: "Technical Specification Group working methods".
3 Definitions 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].
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
BSF Binding Support Function
DNN Data Network Name
DRA Diameter Routing Agent
HTTP Hypertext Transfer Protocol
FQDN Fully Qualified Domain Name
GPSI Generic Public Subscription Identifier
JSON JavaScript Object Notation HTTP Hypertext Transfer Protocol
MAC Media Access Control
NEF Network Exposure Function
NRF Network Repository Function
PCF Policy Control Function
SMF Session Management Function
S-NSSAI Single Network Slice Selection Assistance Information
SUPI Subscription Permanent Identifier
UDR Unified Data Repository
4 Binding Support Management Service
4.1 Service Description
4.1.1 Overview
The Binding Support Management Service as defined in 3GPP TS 23.502 [3] and 3GPP TS 23.503 [4], is provided by
the Binding Support Function (BSF).
The Nbsf_Management service is used for the BSF to provide a PDU session binding functionality, which ensures that
an AF request for a certain PDU Session reaches the relevant PCF holding the PDU Session information.
This service:
- allows NF service consumers to register, update and remove the binding information; and
- allows NF service consumers to retrieve the binding information.
4.1.2 Service Architecture
The 5G System Architecture is defined in 3GPP TS 23.501 [2]. The Policy and Charging related 5G architecture is also
described in 3GPP TS 23.503 [4] and 3GPP TS 29.513 [5].
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The Binding Support Management Service (Nbsf_Management) is exhibited by the Binding Support Function (BSF).
Known consumers of the Nbsf_management service are:
- Policy Control Function (PCF)
- Network Exposure Function (NEF)
- Application Function (AF)
As described in 3GPP TS 23.503 [4], the BSF is a function that can be deployed standalone or can be the functionality
provided by other network functions, such as PCF, UDR, NRF, SMF.
NOTE: The PCF accesses the Nbsf_management service at the BSF via an internal interface when it is collocated
with BSF.
BSF
Nbsf
Nbsf_management service
PCF NEF AF

Figure 4.1.2-1: Reference Architecture for the Nbsf_management service; SBI representation
4.1.3 Network Functions
4.1.3.1 Binding Support Function (BSF)
The BSF:
- stores the binding information for a certain PDU Session; and
- discovers the binding information (e.g. the address information of the selected PCF).
The BSF allows NF service consumers (e.g.PCF) to register, update and remove the binding information, and allows NF
service consumers (e.g. AF, NEF) to discover the binding information (e.g the address information of the selected
PCF).
The BSF can be deployed standalone or can be collocated with other network functions, such as PCF, UDR, NRF
andSMF.
4.1.3.2 NF Service Consumers
The Policy Control Function (PCF):
- registers the binding information in the BSF for a UE when an IPv4 address and/or IPv6 prefix is allocated, or a
MAC address is used for the PDU session; and,
- removes the binding information in the BSF when an IPv4 address and/or IPv6 prefix is released, or a MAC
address is not used for the PDU Session.
The Network Exposure Function (NEF):
- provides a means for the Application Functions to securely interact with the Policy framework for policy control
to 3GPP network. During the procedure, it needs to discover the selected PCF by using the
Nbsf_Management_Discovery service operation.
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3GPP TS 29.521 version 15.4.0 Release 15 9 ETSI TS 129 521 V15.4.0 (2019-10)
The Application Function (AF):
- discover the selected PCF by using the Nbsf_Management_Discovery service operation when it is allowed to
interact directly with the policy framework for policy control.
4.2 Service Operations
4.2.1 Introduction
Table 4.2.1-1: Operations of the Nbsf_Management Service
Service operation name Description Initiated by
Nbsf_Management_Register This service operation is used to register the binding NF service consumer
information for a UE when an IPv4 address and/or an (PCF)
IPv6 prefix is allocated for an IP PDU Session or a MAC
address is used for an Ethernet PDU session.
Nbsf_Management_Deregister This service operation is used to deregister the binding NF service consumer
information for a UE when the PDU Session is released. (PCF)
Nbsf_Management_Discovery This service operation is used by an NEF or AF to NF service consumer
discover a selected PCF . (NEF, AF)

4.2.2 Nbsf_Management_Register Service Operation
4.2.2.1 General
This service operation allows the NF service consumer (e.g. PCF) to register the session binding information for a UE
in the BSF by providing the user identity, the DNN, the UE address(es) and the selected PCF address for a certain PDU
Session to the BSF, and BSF stores the information.
If the NF service consumer (e.g. PCF) receives a new UE address (e.g. IPv6 prefix) and already registered session
binding information for this PDU session, the NF service consumer (e.g. PCF) shall register a new session binding
information in the BSF.
NOTE: For a PDU session, the PCF can receive a new UE address by Npcf_SMPolicyControl_Update service
operation.
4.2.2.2 Register a new PCF Session binding information
NF Service
BSF
Consumer
1. POST ./pcfBindings
2. 201 Created

Figure 4.2.2.2-1: NF service consumer register a new PCF Session binding information
The NF service consumer shall invoke the Nbsf_Management_Register service operation to register the session binding
information for a UE in the BSF. The NF service consumer shall send an HTTP POST request with "{apiRoot}/nbsf-
management/v1/pcfBindings" as Resource URI representing the "PCF Session Bindings", as shown in figure 4.2.2.2-1,
step 1, to create a binding information for an "Individual PCF Session Binding" according to the information (e.g. UE
address(es), SUPI, GPSI, DNN, S-NSSAI) in message body. The PcfBinding data structure provided in the request
body shall include:
- address information of the served UE consisting of:
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(i) either IP address information consisting of:
+ the IPv4 address encoded as "ipv4Addr" attribute; and/or
+ the IPv6 address prefix encoded as "ipv6Prefix" attribute; or
(ii) the MAC address encoded as "macAddr48" attribute; and
- PCF address information consisting of:
(i) if the PCF supports the Npcf_PolicyAuthorization service:
+ the FQDN of the PCF encoded as "pcfFqdn" attribute; and/or
+ a description of IP endpoints at the PCF hosting the Npcf_PolicyAuthorization service encoded as
"pcfIpEndPoints" attribute; and
(ii) if the PCF supports the Rx interface,
+ the Diameter host id of the PCF encoded as "pcfDiamHost"; and
+ the Diameter realm of the PCF and "pcfDiamRealm" attributes;
- DNN encoded as "dnn" attribute; and
- S-NSSAI encoded as "snssai" attribute;
and may include:
- SUPI encoded as "supi" attribute;
- GPSI encoded as "gpsi" attribute;
- IPv4 address domain encoded as "ipDomain" attribute.
Upon the reception of an HTTP POST request with: "{apiRoot}/nbsf-management/v1/pcfBindings" as Resource URI
and PcfBinding data structure as request body, the BSF shall:
- create new binding information;
- assign a bindingId; and
- store the binding information.
The PCF as NF service consumer may provide PCF Id in "pcfId" attribute and recovery timestamp in "recoveryTime"
attribute. The BSF may use the "pcfId" attribute to supervise the status of the PCF as described in subclause 5.2 of
3GPP TS 29.510 [12] and perform necessary cleanup upon status change of the PCF later, and/or both the "pcfId"
attribute and the "recoveryTime" attribute in cleanup procedure as described in subclause 6.4 of 3GPP TS 23.527 [17].
If the BSF created an "Individual PCF Session Binding" resource, the BSF shall respond with "201 Created" with the
message body containing a representation of the created binding information, as shown in figure 4.2.2.2.2-1, step 2. The
BSF shall include a Location HTTP header field. The Location header field shall contain the URI of the created binding
information i.e. "{apiRoot}/nbsf-management/v1/pcfBindings/{bindingId}".
4.2.3 Nbsf_Management_Deregister Service Operation
4.2.3.1 General
This service operation allows the service consumer to remove the session binding information for a UE in the BSF. It is
executed by deleting a given resource identified by an "Individual PCF Session Binding" resource identifier. The
operation is invoked by issuing an HTTP DELETE request on the URI representing the specific session binding
information.
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4.2.3.2 Deregister an individual PCF Session binding information
NF service
BSF
consumer
1. DELETE …/pcfBindings/{bindingId}
2. 204 No Content

Figure 4.2.3.2-1: Session Binding Information Deregistration
The NF service consumer shall invoke the Nbsf_Management_DeRegister service operation to deregister the session
binding information for a UE in the BSF. The NF service consumer shall send an HTTP DELETE request with
"{apiRoot}/nbsf-management/v1/pcfBindings/{bindingId}" as Resource URI, where "{bindingId}" is the "Individual
PCF Session Binding" resource identifier that is to be deleted.
Upon the the reception of an HTTP DELETE request with: "{apiRoot}/nbsf-management/v1/pcfBindings/{bindingId}"
as Resource URI, the BSF shall:
- remove the corresponding binding information.
If the HTTP DELETE request message from the NF service consumer is accepted, the BSF shall respond with "204 No
Content". If the Individual PCF Session Binding resource does not exist, the BSF shall respond with "404 Not Found".
4.2.4 Nbsf_Management_Discovery Service Operation
4.2.4.1 General
This service operation allows the service consumer to use the HTTP GET method to obtain the address information of
the selected PCF.
4.2.4.2 Retrieve the PCF Session binding information for a given tuple
NF service
BSF
consumer
1. GET …/pcfBind
...