ETSI TS 124 623 V15.1.0 (2019-07)

TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
Extensible Markup Language (XML)
Configuration Access Protocol (XCAP)
over the Ut interface for Manipulating Supplementary Services
(3GPP TS 24.623 version 15.1.0 Release 15)


3GPP TS 24.623 version 15.1.0 Release 15 1 ETSI TS 124 623 V15.1.0 (2019-07)

Reference
RTS/TSGC-0124623vf10
Keywords
GSM,LTE,UMTS
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ETSI
3GPP TS 24.623 version 15.1.0 Release 15 2 ETSI TS 124 623 V15.1.0 (2019-07)
Intellectual Property Rights
Essential patents
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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
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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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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 . 8
4 Architecture for manipulating supplementary services settings . 9
5 The eXtensible Markup Language (XML) Configuration Access Protocol (XCAP) . 9
5.1 Introduction . 9
5.2 Functional entities . 10
5.2.1 User Equipment (UE) . 10
5.2.1.1 General . 10
5.2.1.2 Subscription for notification of state changes in XML document . 10
5.2.1.3 Policy on access type used for XCAP . 10
5.2.2 Authentication Proxy (AP) . 12
5.2.2.1 Introduction . 12
5.2.2.2 Authentication . 13
5.2.2.2.0 General . 13
5.2.2.2.1 Authentication based on the generic authentication architecture . 13
5.2.2.2.2 Void . 13
5.2.2.3 Authorization . 13
5.2.3 Application Server (AS) . 14
5.2.3.1 General . 14
5.2.3.2 Authentication and authorization . 14
5.2.3.2.0 General . 14
5.2.3.2.1 HTTP digest authentication . 14
5.2.3.3 Subscription acceptance and notification of state changes in XML document . 15
5.2.3.4 Validation against service capability . 15
5.3 Roles . 15
5.3.1 XCAP client . 15
5.3.1.1 Introduction . 15
5.3.1.2 Manipulating supplementary services . 15
5.3.1.2.1 General . 15
5.3.1.2.2 U E temporarily prevented from manipulating supplementary service settings via XCAP . 16
5.3.1.2.3 Supplementary service settings manipulation errors . 16
5.3.1.2.4 HTTP retry when no response is received . 16
5.3.1.3 Password change . 16
5.3.2 XCAP server . 17
5.3.2.1 Introduction . 17
5.3.2.2 Manipulation acceptance . 17
5.3.2.3 User not allowed to manipulate settings via XCAP . 17
5.3.2.4 Supplementary Service subscription errors . 17
5.3.2.5 Password management . 18
5.3.2.5.1 General . 18
5.3.2.5.2 Password check . 18
5.3.2.5.3 Password change . 19
6 Supplementary services XCAP application usage . 19
6.1 Structure of the XML document . 19
6.2 XCAP application usage . 20
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6.3 XML schema . 22
6.4 Template for a supplementary service XML schema . 23
6.5 XML schema for password change . 23
Annex A (informative): Void . 25
Annex B (normative): Connectivity Aspects when using XCAP . 26
B.1 Scope . 26
B.2 Procedures at the UE . 26
Annex C (normative): IP-Connectivity Access Network specific concepts when using EPS to
access IM CN subsystem . 27
C.1 Scope . 27
C.2 Application usage of XCAP . 27
C.2.1 Procedures at the UE . 27
C.2.1.1 3GPP PS data off . 27
C.2.1.1.1 General . 27
C.2.1.1.2 Enforcement . 27
Annex D (normative): IP-Connectivity Access Network specific concepts when using GPRS
to access IM CN subsystem . 28
D.1 Scope . 28
D.2 Application usage of XCAP . 28
D.2.1 Procedures at the UE . 28
D.2.1.1 3GPP PS data off . 28
D.2.1.1.1 General . 28
D.2.1.1.2 Enforcement . 28
Annex E (normative): IP-Connectivity Access Network specific concepts when using 5GS to
access an IM CN subsystem . 29
E.1 Scope . 29
E.2 Application usage of XCAP . 29
E.2.1 Procedures at the UE . 29
E.2.1.1 3GPP PS data off . 29
E.2.1.1.1 General . 29
E.2.1.1.2 Enforcement . 29
Annex F (informative): Change history . 30
History . 32

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Foreword
This Technical Specification (TS) was been produced by ETSI Technical Committee Telecommunications and Internet
converged Services and Protocols for Advanced Networking (TISPAN) and originally published as ETSI TS 183 023
[13]. It was transferred to the 3rd Generation Partnership Project (3GPP) in January 2008.
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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1 Scope
The present document defines a protocol used for manipulating data related to supplementary services. The protocol is
based on the eXtensible Markup Language (XML) Configuration Access Protocol (XCAP) RFC 4825 [8]. A new
XCAP application usage is defined for the purpose of manipulating the supplementary services data. The common
XCAP related aspects that are applicable to supplementary services are specified in the present document. The protocol
allows authorized users to manipulate service-related data either when they are connected to IMS or when they are
connected to non-IMS networks (e.g. the public Internet).
The present document is applicable to User Equipment (UE) and Application Servers (AS) which are intended to
support XCAP application usage for manipulating data related to supplementary services.
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] IETF RFC 2616: "Hypertext Transfer Protocol - HTTP/1.1".
[2] W3C REC-xmlschema-1-20010502: "XML Schema Part 1: Structures".
[3] IETF RFC 2617: "HTTP Authentication: Basic and Digest Access Authentication".
[4] IETF RFC 2246: "The TLS Protocol Version 1.0".
[5] 3GPP TS 24.109: "Bootstrapping interface (Ub) and Network application function interface (Ua);
Protocol details".
[6] 3GPP TS 33.222: "Generic Authentication Architecture (GAA); Access to network application
functions using Hypertext Transfer Protocol over Transport Layer Security (HTTPS)".
[7] Void.
[8] IETF RFC 4825: "The Extensible Markup Language (XML) Configuration Access Protocol
(XCAP)".
[9] Void
[10] Void.
[11] IETF RFC 5875 (May 2010): "An Extensible Markup Language (XML) Configuration Access
Protocol (XCAP) Diff Event Package".
[12] ETSI TS 183 038: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); PSTN/ISDN Simulation Services; Extensible Markup
Language (XML) Document Management; Protocol Specification (Endorsement of
OMA-TS-XDM-Core-V1-0-20051103-C and OMA-TS-XDM-Shared-V1-0-20051006-C)".
[13] ETSI TS 183 023 V1.4.0: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); PSTN/ISDN simulation services; Extensible Markup Language
(XML) Configuration Access Protocol (XCAP) over the Ut interface for Manipulating NGN
PSTN/ISDN Simulation Services".
[14] OMA-TS-XDM_Core-V1_1-20080627-A: "XML Document Management (XDM) Specification".
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[15] 3GPP TS 23.003: "Numbering, addressing and identification".
[15A] 3GPP TS 31.103: "Characteristics of the IP multimedia services identity module (ISIM)
application".
[15B] 3GPP TS 31.102: "Characteristics of the Universal Subscriber Identity Module (USIM)
application".
[16] 3GPP TS 24.315: "IP Multimedia Subsystem (IMS) Operator Determined Barring (ODB);
Stage 3".
[17] 3GPP TS 33.141: "Presence service; Security".
[18] IETF RFC 6665 (July 2012): "SIP-Specific Event Notification".
[19] 3GPP TS 24.167: "3GPP IMS Management Object (MO); Stage 3".
[20] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[21] 3GPP TS 33.310: "Network Domain Security (NDS); Authentication Framework (AF)".
[22] 3GPP TS 24.424: "Management Object (MO) for Extensible Markup Language (XML)
Configuration Access Protocol (XCAP) over the Ut interface for Manipulating Supplementary
Services (SS)".
[23] 3GPP TS 22.030: "Man-Machine Interface (MMI) of the User Equipment (UE)".
[24] 3GPP TS 22.011: "Service accessibility".
[25] 3GPP TS 24.229: "IP multimedia call control protocol based on Session Initiation Protocol (SIP)
and Session Description Protocol (SDP); Stage 3".[26] 3GPP TS 29.292: "Interworking between
the IP Multimedia (IM) Core Network (CN) subsystem (IMS) and MSC Server for IMS
Centralized Services (ICS)".
[27] Void.
[28] Void.
[29] 3GPP TS 24.008: "Mobile Radio Interface Layer 3 specification; Core Network Protocols;
Stage 3".
[30] 3GPP TS 24.301: "Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS);
Stage 3".
[31] 3GPP TS 24.302: "Access to the 3GPP Evolved Packet Core (EPC) via non-3GPP access
networks; Stage 3".
[32] 3GPP TS 24.244: "Wireless LAN control plane protocol for trusted WLAN access to EPC".
[33] 3GPP TS 24.501: "Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3".
[34] 3GPP TS 24.502: "Access to the 3GPP 5G Core Network (5GCN) via non-3GPP access
networks".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [20] and IETF RFC 4825 [8]
apply.
SS configuration via XCAP: supplementary services (SS) configuration based on XCAP protocol sent over the Ut
interface.
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For the purposes of the present document, the following terms and definitions given in 3GPP TS 22.011 [24] apply:
3GPP PS data off
3GPP PS data off exempt service
For the purposes of the present document, the following terms and definitions given in 3GPP TS 24.229 [25] apply:
3GPP PS data off status
For the purposes of the present document, the following terms and definitions given in 3GPP TS 24.501 [33] apply:
NG-RAN
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
5GCN 5G Core Network
5GS 5G System
AP Authentication Proxy
AS Application Server
AUID Application Unique ID
EPS Evolved Packet System
GPRS General Packet Radio Service
HTTP HyperText Transfer Protocol
IMS IP Multimedia Subsystem
IP-CAN IP Connectivity Access Network
ISDN Integrated Services Digital Network
MIME Multipurpose Internet Mail Extensions
MMI Man-Machine Interface
NAF Network Application Function
NGN Next Generation Network
NG-RAN Next Generation Radio Access Network
ODB Operator Determined Barring
PS Packet Switched
PSTN Public Switched Telephone Network
SS Supplementary Service
TLS Transport Layer Security
UE User Equipment
URI Uniform Resource Identifier
WPA Wrong Password Attempts
XCAP XML Configuration Access Protocol
XML eXtended Markup Language
XUI XCAP User Identifier
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4 Architecture for manipulating supplementary services
settings
The protocol described in the present document allows to manipulate settings and variables related that influence the
execution of one or more supplementary services. Manipulation of the supplementary services take place over the Ut
interface (UE to AS), as shown in figure 1.
UE AS
Ut
Figure 1: Ut interface
Manipulation of supplementary services does not usually take place during real-time operation. Typically users
manipulate their services configuration data prior to the invocation and execution of the service.
Authentication of the user with HTTP may take place directly at the AS, such as in figure 1, or with the support of an
Authentication Proxy, such as in figure 2. The architecture for authentication is provided in 3GPP TS 33.222 [6].
NOTE: The Network Application Function (NAF) can be an AS.
Authentication
UE AS
Proxy
Ut Ut
Figure 2: Authentication proxy in the Ut interface path
5 The eXtensible Markup Language (XML)
Configuration Access Protocol (XCAP)
5.1 Introduction
For the purpose of manipulating data stored in an application server the XML Configuration Access Protocol
(XCAP) [8] is used. XCAP allows a client to read, write and modify application configuration data, stored in XML
format on a server. XCAP maps XML document sub-trees and element attributes to HTTP URIs, so that these
components can be directly accessed by HTTP (see IETF RFC 2616 [1]). XCAP uses the HTTP methods PUT, GET,
and DELETE to operating on XML documents stored in the server.
In the case of supplementary services, the data stored in a server is related to the execution of that given service. The
present document defines a new XCAP Application Usage for the purpose of allowing a client to manipulate data
related to supplementary services.
XCAP (see IETF RFC 4825 [8]) defines two logical roles: XCAP client and XCAP servers. An XCAP client is an
HTTP/1.1 compliant client. Similarly an XCAP server is an HTTP/1.1 compliant server. The XCAP server acts as a
repository of XML documents that customize and modify the execution of the supplementary services. Figure 3 depicts
the XCAP architecture where an XCAP client sends an HTTP/1.1 request to an XCAP server. The server replies with an
HTTP/1.1 response.
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XCAP XCAP
client server
HTTP request
HTTP response
Figure 3: XCAP architecture
According to XCAP (see IETF RFC 4825 [8]), each application that makes use of XCAP defines its own XCAP
application usage. The present document defines an supplementary services XCAP application usage in clause 6. This
application usage defines the XML schema W3C REC-xmlschema-1-20010502 [2] for the data used by the application,
along with other key pieces of information.
XCAP focuses on the definition of XML documents that are compliant with the XML schema and constrains defined
for a particular XCAP application usage. XCAP allows application to provide XML documents that are common for all
users or XML documents that affect the service of a given user.
Central to XCAP is the construction of the HTTP URI that points to particular XML document or certain components of
it. A component in an XML document can be an XML element, attribute, or the value of it.
5.2 Functional entities
5.2.1 User Equipment (UE)
5.2.1.1 General
The UE implements the role of an XCAP client, as described in subclause 5.3.1 accessing the XCAP application usage
as described in subclause 6.2.
For systems where Generic Authentication Architecture [6] is used, the UE shall support the authentication mechanisms
specified in 3GPP TS 33.222 [6] and 3GPP TS 24.109 [5].
For systems where Generic Authentication Architecture [6] is not used, the UE shall support IETF RFC 2617 [3]
according to ETSI TS 183 038 [12] and shall support the TLS profile specified in 3GPP TS 33.310 [21] annex E in all
procedures of ETSI TS 183 038 [12] where TLS support according to IETF RFC 2246 [4] is specified.
For systems where Generic Authentication Architecture [6] is not used, the UE may support the authentication
mechanisms specified in 3GPP TS 33.141 [17] annex D.
On sending an HTTP request, the UE may indicate the user's identity intended to be used with the AS by adding a
HTTP X-3GPP-Intended-Identity header (3GPP TS 24.109 [5]) to the outgoing HTTP request. If the authentication
mechanism specified in 3GPP TS 33.141 [17] annex D is used, the UE shall add a HTTP X-3GPP-Intended-Identity
header field.
5.2.1.2 Subscription for notification of state changes in XML document
In order to keep the supplementary services state synchronized with the network elements and other terminals that the
user might be using, the UE should subscribe to changes in the XCAP simserv documents by generating a SUBSCRIBE
request in accordance with RFC 5875 [11] and RFC 6665 [18].
5.2.1.3 Policy on access type used for XCAP
The policy on access type used for the XCAP enables HPLMN control of access used for XCAP messages.
The policy on access type used for the XCAP can be set to one of the following values:
a) any access type;
b) 3GPP accesses only;
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c) EPC or 5GCN via WLAN IP-CAN only;
d) Non-seamless WLAN offload only;
e) 3GPP accesses preferred, non-seamless WLAN offload as secondary; and
f) 3GPP accesses preferred, EPC or 5GCN via WLAN IP-CAN as secondary.
The UE may support the policy on access type used for the XCAP.
If the UE supports the policy on access type used for the XCAP:
a) when the UE needs to send an XCAP request:
1) if the policy on access type used for the XCAP is set to "any access type", the UE shall send XCAP requests
from an IP address associated with a bearer of any access;
2) if the policy on access type used for the XCAP is set to "3GPP accesses only":
A) the UE shall attempt to obtain a PDP context for XCAP as specified in 3GPP TS 24.008 [29] or a EPS
bearer context for XCAP as specified in 3GPP TS 24.301 [30] or a 5GS QoS flow using NG-RAN as
specified in 3GPP TS 24.501 [33];
B) if the UE obtains the PDP context for XCAP or the EPS bearer context for XCAP, the UE shall send
XCAP requests from an IP address associated with the obtained PDP context for XCAP or the obtained
EPS bearer context for XCAP or the 5GS QoS flow using NG-RAN; and
C) if the UE cannot obtain the PDP context for XCAP or the EPS bearer context for XCAP or the 5GS QoS
flow using NG-RAN, the UE shall not send XCAP request;
3) if the policy on access type used for the XCAP is set to "EPC via WLAN IP-CAN only":
A) the UE shall attempt to associate with a WLAN as specified in 3GPP TS 24.302 [31] or as specified in
3GPP TS 24.502 [34] and the UE shall attempt to obtain:
- a PDN connection for XCAP as specified in 3GPP TS 24.302 [31], or 3GPP TS 24.244 [32]; or
- a 5GS QoS flow using WLAN as specified in 3GPP TS 24.502 [34];
B) if the UE obtains the PDN connection or 5GS QoS flow for XCAP, the UE shall send XCAP requests
from an IP address associated with the PDN connection or 5GS QoS flow for XCAP; and
C) if the UE cannot obtain the PDN connection or 5GS QoS flow for XCAP, the UE shall not send XCAP
request;
4) if the policy on access type used for the XCAP is set to "Non-seamless WLAN offload only":
A) the UE shall attempt to associate with a WLAN as specified in 3GPP TS 24.302 [31];
B) if the UE associates with a WLAN and the WLAN is either untrusted non-3GPP access or the UE
established NSWO via TWAN, the UE shall send XCAP requests from an IP address associated with the
WLAN; and
C) if the UE cannot associate with a WLAN or the UE associates with TWAN and NSWO is not available,
the UE shall not send an XCAP request;
5) if the policy on access type used for the XCAP is set to "3GPP accesses preferred, non-seamless WLAN
offload as secondary":
A) the UE shall attempt to obtain a PDP context for XCAP as specified in 3GPP TS 24.008 [29] or a EPS
bearer context for XCAP as specified in 3GPP TS 24.301 [30] or a 5GS QoS flow for XCAP as specified
in 3GPP TS 24.501 [33];
B) if the UE obtains the PDP context for XCAP or the EPS bearer context for XCAP or a 5GS QoS flow for
XCAP, the UE shall send XCAP requests from an IP address associated with the obtained PDP context
for XCAP or the obtained EPS bearer context for XCAP; and
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C) if the UE cannot obtain the PDP context for XCAP or the EPS bearer context for XCAP or a 5GS QoS
flow for XCAP:
i) the UE shall attempt to associate with a WLAN as specified in 3GPP TS 24.302 [31];
ii) if the UE associates with a WLAN and the WLAN is either untrusted non-3GPP access or the UE
established NSWO via TWAN, the UE shall send XCAP requests from an IP address associated with
the WLAN; and
iii) if the UE cannot associate with a WLAN or the UE associates with TWAN and NSWO is not
available, the UE shall not send XCAP request; and
6) if the policy on access type used for the XCAP is set to "3GPP accesses preferred, EPC or 5GCN via WLAN
IP-CAN as secondary":
A) the UE shall attempt to obtain a PDP context for XCAP as specified in 3GPP TS 24.008 [29] or a EPS
bearer context for XCAP as specified in 3GPP TS 24.301 [30] or a 5GS QoS flow using NG-RAN as
specified in 3GPP TS 24.501 [33];
B) if the UE obtains the PDP context for XCAP, the EPS bearer context for XCAP or the 5GS QoS flow for
XCAP, the UE shall send XCAP requests from an IP address associated with the obtained PDP context
for XCAP or the obtained EPS bearer context for XCAP or the 5GS QoS flow using NG-RAN; and
C) if the UE cannot obtain the PDP context for XCAP or the EPS bearer context for XCAP or the 5GS QoS
flow using NG-RAN:
i) the UE shall attempt to associate with a WLAN as specified in 3GPP TS 24.302 [31] or as specified in
3GPP TS 24.502 [34] and the UE shall attempt to obtain:
- a PDN connection for XCAP as specified in 3GPP TS 24.302 [31] or as specified in
3GPP TS 24.502 [34], or 3GPP TS 24.244 [32];
- a 5GS QoS flow using WLAN as specified in 3GPP TS 24.502 [34];
ii) if the UE obtains the PDN connection or 5GS QoS flow for XCAP, the UE shall send XCAP requests
from an IP address associated with the PDN connection or 5GS QoS flow for XCAP; and
iii) if the UE cannot obtain the PDN connection or 5GS QoS flow for XCAP, the UE shall not send
XCAP request; and
b) the UE may support being configured with the policy on access type used for the XCAP using one or more of the
following methods:
a) the EF file described in 3GPP TS 31.102 [15B];
XCAPConfigData
b) the EF file described in 3GPP TS 31.103 [15A]; and
XCAPConfigData
c) the AccessForXCAP node of 3GPP TS 24.424 [22].
If the UE is configured with both the AccessForXCAP node of 3GPP TS 24.424 [22] and the EF file
XCAPConfigData
described in 3GPP TS 31.102 [15B] or 3GPP TS 31.103 [15A], then the EF file shall take precedence.
XCAPConfigData
NOTE: Precedence for files configured on both the USIM and ISIM is defined in 3GPP TS 31.102 [15B].
5.2.2 Authentication Proxy (AP)
5.2.2.1 Introduction
An Authentication Proxy is an HTTP/1.1 IETF RFC 2616 [1] compliant server whose main purpose is to authenticate
the user requests. The Authentication Proxy is used to separate the authentication procedure and the Application Server
(AS) specific application logic to different logical entities.
The AP is configured as a HTTP reverse proxy, i.e. the FQDN of the AS is configured to the AP such a way that the IP
traffic intended to the AS is directed to the AP by the network. The AP performs the authentication of the UE. After the
authentication procedure has been successfully completed, the AP assumes the typical role of a reverse proxy, i.e. the
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AP forwards HTTP requests originating from the UE to the correct AS, and returns the corresponding HTTP responses
from the AS to the originating UE.
The AP allows authorized users to manipulate services when they are connected to an IMS network or when they are
connected to a non-IMS network (e.g. the public Internet). Authentication details can differ in both situations.
Provisioning of credentials to authenticate the user is outside the scope of the present document. 3GPP TS 33.222 [6]
provides further architectural authentication details.
NOTE: Multiple APs can exist between the UE and the AS, and the UE can obtain a list of different AP addresses
via DNS query.
5.2.2.2 Authentication
5.2.2.2.0 General
On receiving an HTTP request, the AP shall first determine the mechanism used to authenticate the user. If the Generic
Authentication Architecture [6] is used, the AP shall attempt to authenticate the user via the mechanisms specified
in 3GPP TS 33.222 [6] and the AP shall follow the procedures indicated in subclause 5.2.2.2.1. For systems where
Generic Authentication Architecture 3GPP TS 33.222 [6] is not used, the AP shall attempt to authenticate the user
according to IETF RFC 2617 [3] (ETSI TS 183 038 [12] provides guidelines for the Authentication Proxy) or
3GPP TS 33.141 [17] annex D.
5.2.2.2.1 Authentication based on the generic authentication architecture
On receiving an HTTP request that contains the Authorization header field, the AP shall:
a) use the value of that username parameter of the Authorization header field to authenticate the user;
b) apply the procedures specified in IETF RFC 2617 [3] for authentication;
c) if the HTTP request contains an X-3GPP-Intended-Identity header field (3GPP TS 24.109 [5]), then the AP may
verify that the user identity belongs to the subscriber. This verification of the user identity shall be performed
dependant on the subscriber's application specific or AP specific user security settings;
d) if authentication is successful, remove the Authorization header field from the HTTP request;
e) insert an HTTP X-3GPP-Asserted-Identity header field (3GPP TS 24.109 [5]) that contains the asserted identity
or a list of identities; and
f) forward the HTTP request to the appropriate AS.
On receiving an HTTP response for the previous request, the AP shall:
a) add an Authentication-Info header field in accordance to the procedures described in 3GPP TS 33.222 [6]; and
b) forward the response to the XCAP client.
On receiving an HTTP request that does not contain the Authorization header field, the AP shall:
a) challenge the user by generating a 401 Unauthorized response according to the procedures specified
in 3GPP TS 33.222 [6] and IETF RFC 2617 [3]; and
b) forward the 401 Unauthorized response to the sender of the HTTP request.
5.2.2.2.2 Void
5.2.2.3 Authorization
The AP shall be able to decide whether particular subscriber, i.e. the UE, is authorized to access a particular AS. On
doing so, the AP may use the User Security Settings specified in 3GPP TS 24.109 [5].
The AP may indicate an asserted identity or a list of identities to the AS by adding an HTTP X-3GPP-Asserted-Identity
header field to the HTTP requests prior to forwarding the request to the AS. In case of multiple identities, they shall be
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separated by comma (,) and each identity shall be surrounded by quotation marks ("). Whether the AP supports this
handling of an asserted identity or a list of identities then it shall depend on local policy in the AP. In addition the
subscriber's application specific or AP specific user security settings may be considered.
The AP may indicate an authorization flag or a list of authorization flags from the application specific user security
settings (USS) to the AS by adding a HTTP X-3GPP-Authorization-Flags header field to the HTTP request prior to
forward it to the XCAP server. The HTTP X-3GPP-Authorization-Flags header field shall contain a list of authorization
flags separated by comma (,) and each authorization flag is surrounded by quotation marks ("). In case the AP supports
this handling of authorization flags from USS then it shall depend on local policy in the AP.
5.2.3 Application Server (AS)
5.2.3.1 General
An Application Server implements the role of an XCAP server as described in subclause 5.3.2 providing the XCAP
application usage as described in subclause 6.2.
For systems where Generic Authentication Architecture [6] is used, the AS shall support the authentication mechanisms
specified in 3GPP TS 33.222 [6] and 3GPP TS 24.109 [5].
For systems where Generic Authentication Architecture [6] is not used, the AS shall support IETF RFC 2617 [3]
according to ETSI TS 183 038 [12] and shall support the TLS profile specified in 3GPP TS 33.310 [21] annex E in all
procedures of ETSI TS 183 038 [12] where TLS support according to IETF RFC 2246 [4] is specified.
Procedures regarding Operator Determined Barring (ODB) are defined in 3GPP TS 24.315 [16].
For systems where Generic Authentication Architecture [6] is not used, the AS may support the authentication
mechanisms specified in 3GPP TS 33.141 [17] annex D.
5.2.3.2 Authentication and authorization
5.2.3.2.0 General
If an Authentication Proxy (AP) is provided in the path of the HTTP request, then the AS receives an HTTP request
from a trusted source (the AP) and contains an HTTP X-3GPP-Asserted-Identity header (3GPP TS 24.109 [5]) that
includes an asserted identity of the user. In this case the AS does not need to authenticate the user, but just provide
authorization to access the requested resource.
If an HTTP X-3GPP-Asserted-Identity header (3GPP TS 24.109 [5]) is not present in the HTTP request or if the request
is received from a non-trusted source, then the AS needs to authenticate the user prior to providing authorization to the
XCAP resource by applying the procedures of authentication mechanisms specified in 3GPP TS 33.222 [6] and
3GPP TS 24.109 [5] in case Generic Authentication Architecture is selected,
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