ETSI TS 123 221 V15.1.0 (2019-03)

Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; Architectural requirements (3GPP TS 23.221 version 15.1.0 Release 15)

RTS/TSGS-0223221vf10

General Information

• Status: Published
• Publication Date: 10-Mar-2019
• Technical Committee: 3GPP SA 2 - Architecture
• Current Stage: 12 - Completion
• Completion Date: 11-Mar-2019

Standards Content (Sample)

ETSI TS 123 221 V15.1.0 (2019-03)






TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
Architectural requirements
(3GPP TS 23.221 version 15.1.0 Release 15)

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3GPP TS 23.221 version 15.1.0 Release 15 1 ETSI TS 123 221 V15.1.0 (2019-03)



Reference
RTS/TSGS-0223221vf10
Keywords
GSM,LTE,UMTS
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3GPP TS 23.221 version 15.1.0 Release 15 2 ETSI TS 123 221 V15.1.0 (2019-03)
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
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Foreword
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, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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3GPP TS 23.221 version 15.1.0 Release 15 3 ETSI TS 123 221 V15.1.0 (2019-03)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 6
1 Scope . 7
2 References . 7
3 Definitions, symbols and abbreviations . 8
3.1 Definitions . 8
3.2 Symbols . 9
3.3 Abbreviations . 9
4 3GPP system domains and subsystems . 10
4.1 Allowed network and terminal configurations . 10
4.2 Circuit switched (CS) core network domain . 10
4.2.1 Iu mode to Iu mode handover for circuit switched services . 10
4.2.2 A mode to Iu mode handover for CS services . 11
4.2.3 General principles for use of CS-MGW resources . 11
4.2.4 Transcoder location. 11
4.3 Packet Switched (PS) core network domain . 11
4.4 IP Multimedia subsystem (IMS) . 11
4.5 Cross Core Network Domain Requirements . 11
4.6 UTRAN . 12
4.7 GERAN . 12
4.8 E-UTRAN . 12
5 IP addressing . 12
5.1 IP version issues . 12
5.2 Interoperability between IPv4 and IPv6 networks . 12
5.2.1 IPv4/IPv6 Mobile connecting to IPv4 and IPv6 networks . 13
5.2.2 IPv6 only Mobile connecting to IPv4 network . 13
5.2.3 IPv6 Mobile connected to an IPv6 Device via an IPv4 network . 14
5.3 Address management . 14
5.4 IP addressing and routing for access to IM-subsystem services . 15
5.5 Simultaneous access to multiple services . 16
5.6 UE support of IPv6 . 17
5.7 IP addressing and routing for server/application . 18
6 Mobility management. 18
6.1 Introduction . 18
6.2 Location management and mobility management concept overview . 18
6.2.1 Non-combined procedures . 18
6.2.2 Use of combined procedures . 20
6.3 Description of the location management and mobility management concept - area concepts . 21
6.3.1 Introduction. 21
6.3.2 Location areas . 21
6.3.3 Tracking and Routing areas . 21
6.3.3a Support of Iu and A/Gb mode of operation in GERAN Cells . 21
6.3.3a.1 Overview . 21
6.3.3a.2 Interface selection in GERAN Cells . 22
6.3.3a.2.1 Basic principles for MS controlled Cell/Mode selection/re-selection . 22
6.3.3a.2.2 Basic principles for network controlled Mode selection/re-selection . 22
6.3.4 RAN internal areas. 22
6.3.5 Relationship between the different areas . 23
6.3.5a Restriction of subscribers' access . 24
6.3.6 Hierarchical tracking concept . 24
6.4 Relationship between MM and SM states for an UE. 25
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3GPP TS 23.221 version 15.1.0 Release 15 4 ETSI TS 123 221 V15.1.0 (2019-03)
6.5 Requirement in case of temporarily loss of coverage of packet UE . 25
6.6 MM functionality in different UE service states . 25
6.7 The RRC state machine . 26
6.8 Relationship between CS and PS service states and RRC state for an UE . 27
6.9 Service registration and location update . 28
6.9.1 Introduction. 28
6.9.2 Location area update . 28
6.9.3 Tracking and Routing area update . 29
6.9.4 Combined updates . 29
6.10 Paging initiated by CN . 29
6.11 Signalling connection establishment . 29
6.11a CS Domain Signalling Requirements (in particular relating to handover) . 29
6.12 Relations between SRNS relocation and location registration . 30
6.13 Requirements on identifiers for UMTS and GSM . 31
6.14 Use of MM system information . 32
6.15 Signalling procedures . 32
6.15.1 Idle mode procedures . 32
6.15.1.1 Location Area update . 32
6.15.1.2 Routing Area Update. 34
6.15.1.2A Tracking Area Update . 34
6.15.1.3 Periodic registration towards both CN nodes without use of Gs or SGs . 34
6.15.1.4 Periodic registration with use of Gs or SGs . 34
6.15.1.5 UE initiated combined detach procedure when using Gs or SGs . 34
6.15.1.6 Forbidden LA/RA . 34
6.15.2 SRNS Relocation . 34
6.16 RAN coordination . 34
7 Call control . 35
7.1 General Aspects . 35
7.2 Domain selection for mobile terminated calls from the PSTN/CS domain . 35
7.2.1 Introduction. 35
7.2.2 Calls directed to the CS domain. 36
7.2.3 Calls directed to the IMS . 36
7.2a Domain selection for UE originating sessions / calls . 36
7.2b Access Domain Selection for terminating sessions . 38
7.2c Domain Selection for UE originating SMS . 39
7.2d Domain selection decisions during ongoing sessions . 39
7.2e Selection of method for UE originating USSD requests . 40
7.3 Routing sessions from the IMS to the CS Domain . 40
8 Support of IM CN Subsystem services . 40
8.1 Context activation and registration . 40
8.2 Location management . 42
8.2.1 Registration concepts for a subscriber roaming into CS domain . 42
8.3 IMS Emergency sessions . 43
8.3.1 GPRS/EPS considerations for UE recognized IMS Emergency Sessions . 43
8.3.2 Emergency Calls in absence of UICC for GPRS/EPS Access . 43
9 Efficient use of radio resource . 43
Annex A (informative): Guidance for CSFB and IMS enabled UE implementations in E-
UTRAN . 45
A.1 General . 45
A.2 IMS PS Voice preferred . 45
A.2.1 EPS Attach . 45
A.2.2 Combined EPS/IMSI attach . 46
A.3 CS Voice preferred . 46
A.4 IMS PS Voice only . 47
A.5 CS Voice only . 48
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3GPP TS 23.221 version 15.1.0 Release 15 5 ETSI TS 123 221 V15.1.0 (2019-03)
Annex B (informative): Guidance related to IPv4 address usage . 50
B.1 General . 50
B.2 Interworking aspects. 50
B.2.1 Interworking scenario: UE assigned private IPv4 address . 50
B.2.2 Use of Device triggering . 50
B.2.3 Specific APN use . 50
Annex C (informative): Change history . 52
History . 53

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3GPP TS 23.221 version 15.1.0 Release 15 6 ETSI TS 123 221 V15.1.0 (2019-03)
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.
ETSI

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3GPP TS 23.221 version 15.1.0 Release 15 7 ETSI TS 123 221 V15.1.0 (2019-03)
1 Scope
This document covers the architectural requirements for 3GPP systems based on UTRAN, E-UTRAN and Iu mode
GERAN. In particular it details the high level requirements for the Circuit Switched (CS) Domain and the stage 2
procedures that span more than one domain/subsystem. The reference model to which these procedures apply can be
found within TS 23.002 [1]. In addition, A mode to Iu mode handover for CS services is addressed. Detailed
architectural requirements within the subsystems are contained within the remainder of the 23 series of specifications
e.g. the requirements for the Packet Switched (PS) domain are contained within TS 23.060 [2], TS 23.401 [27] and the
requirements for the Bearer Independent CS Core Network are contained in TS 23.205[14].
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 TS 23.002: "Network Architecture".
[2] 3GPP TS 23.060: "General Packet Radio Service (GPRS) Service description; Stage 2".
[3] 3GPP TS 23.012: "Location management procedures".
[5] 3GPP TS 25.331: "Radio Resource Control (RRC) Protocol Specification".
[6] 3GPP TS 25.301: "Radio interface protocol architecture".
[7] 3GPP TS 25.303: "UE functions and inter-layer procedures in connected mode".
[8] 3GPP TR 21.905: "3G Vocabulary".
[9] 3GPP TS 25.413: "UTRAN Iu interface RANAP signalling".
[10] 3GPP TS 25.410: "UTRAN Iu Interface: General Aspects and Principles".
[11] 3GPP TS 23.228: "IP Multimedia Subsystem – Stage 2".
[12] 3GPP TS 43.051: "GERAN Overall Description".
[13] 3GPP TS 23.153: "Out of Band Transcoder Control - Stage 2".
[14] 3GPP TS 23.205: "Bearer Independent CS Core Network – Stage 2".
[15] 3GPP TR 25.931: "UTRAN Functions, examples on signalling procedures".
[16] RFC 2766: "Network Address Translation - Protocol Translation (NAT-PT)", G. Tsirtsis, P.
Srisuresh. February 2000.
[17] RFC 2893: "Transition Mechanisms for IPv6 Hosts and Routers", R. Gilligan, E. Nordmark,
August 2000.
[17a] RFC 4941: "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", T. Narten, R.
Daves, S. Krishnan, September 2007.
[18] 3GPP TS 25.401: "UTRAN Overall Description".
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3GPP TS 23.221 version 15.1.0 Release 15 8 ETSI TS 123 221 V15.1.0 (2019-03)
[19] 3GPP TS 25.304: "UE Procedures in Idle Mode and Procedures for Cell Reselection in Connected
Mode".
[20] 3GPP TS 45.008: "Radio subsystem link control".
[21] RFC3316: "IPv6 for Some Second and Third Generation Cellular Hosts", June 2002.
[22] 3GPP TS 24.007: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface
signalling layer 3 General aspects".
[23] 3GPP TS 24.229: "IP Multimedia Call Control Protocol based on SIP and SDP".
[24] 3GPP TS 23.008: "Organisation of subscriber data".
[25] 3GPP TS 24.008: "Mobile radio interface Layer 3 specification; Core network protocols; Stage 3".
[26] 3GPP TR 23.981: "Interworking aspects and migration scenarios for IPv4 based IMS
implementations".
[27] 3GPP TS 23.401: "General Packet Radio Service (GPRS) enhancements for Evolved Universal
Terrestrial Radio Access Network (E-UTRAN) access".
[28] 3GPP TS 36.300: "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal
Terrestrial Radio Access (E-UTRAN); Overall description; Stage 2".
[29] 3GPP TS 36.331: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource
Control (RRC); Protocol specification".
[30] 3GPP TS 23.272: "Circuit Switched Fallback in Evolved Packet System; Stage 2".
[31] 3GPP TS 23.292: "IP Multimedia Subsystem (IMS) Centralized Services".
[32] 3GPP TS 23.237: "IP Multimedia Subsystem (IMS) Service Continuity".
[33] 3GPP TS 23.167: "IP Multimedia Subsystem (IMS) emergency sessions".
[34] 3GPP TS 24.301: "Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS);
Stage 3".
[35] 3GPP TS 23.216: "Single Radio Voice Call Continuity (SRVCC); Stage 2".
[36] 3GPP TR 23.975: "IPv6 Migration Guidelines".
[37] 3GPP TS 29.061: "Interworking between the Public Land Mobile Network (PLMN) supporting
packet based services and Packet Data Networks (PDN)".
[38] 3GPP TS 23.682: "Architecture Enhancements to facilitate communications with Packet Data
Networks and Applications".
[39] 3GPP TS 22.011: "Service accessibility".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the terms defined in TR 21.905 [8] apply, in addition, the following terms
apply:
3GPP PS Data Off Exempt Services: For PDN Connection or PDU Session of type IP, up to two sets of operator
services (i.e. the exempt services enumerated in clause 10.2 of TS 22.011 [39], including the signalling used to enable
such services) that are allowed even if the 3GPP PS Data Off status set to active in the UE by the user. One set is used
when UE is in HPLMN, the other set is used when UE is roaming in VPLMN. For PDN connection of type non-IP, or
PDU Session of type Ethernet or Unstructured, no 3GPP Data Off Exempt Service is defined.
In Iu mode: see TR 21.905 [8].
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3GPP TS 23.221 version 15.1.0 Release 15 9 ETSI TS 123 221 V15.1.0 (2019-03)
In A
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