ETSI TS 138 423 V15.20.0 (2024-09)

5G; NG-RAN; Xn Application Protocol (XnAP) (3GPP TS 38.423 version 15.20.0 Release 15)

RTS/TSGR-0338423vfk0

General Information

• Status: Not Published
• Technical Committee: 3GPP RAN 3 - lub specification, lur specification, lu specification and UTRAN & O&M
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 26-Sep-2024

Standards Content (Sample)

TECHNICAL SPECIFICATION
5G;
NG-RAN;
Xn Application Protocol (XnAP)
(3GPP TS 38.423 version 15.20.0 Release 15)

3GPP TS 38.423 version 15.20.0 Release 15 1 ETSI TS 138 423 V15.20.0 (2024-09)

Reference
RTS/TSGR-0338423vfk0
Keywords
5G
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - APE 7112B
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° w061004871

Important notice
The present document can be downloaded from:
https://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
If you find a security vulnerability in the present document, please report it through our
Coordinated Vulnerability Disclosure Program:
https://www.etsi.org/standards/coordinated-vulnerability-disclosure
Notice of disclaimer & limitation of liability
The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of
experience to understand and interpret its content in accordance with generally accepted engineering or
other professional standard and applicable regulations.
No recommendation as to products and services or vendors is made or should be implied.
No representation or warranty is made that this deliverable is technically accurate or sufficient or conforms to any law
and/or governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness
for any particular purpose or against infringement of intellectual property rights.
In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not
limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property
rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages
for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use
of or inability to use the software.
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 2024.
All rights reserved.
ETSI
3GPP TS 38.423 version 15.20.0 Release 15 2 ETSI TS 138 423 V15.20.0 (2024-09)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations
pertaining to these essential IPRs, if any, are 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 Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,
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.
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.
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 https://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 38.423 version 15.20.0 Release 15 3 ETSI TS 138 423 V15.20.0 (2024-09)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 10
1 Scope . 11
2 References . 11
3 Definitions, symbols and abbreviations . 12
3.1 Definitions . 12
3.2 Abbreviations . 13
4 General . 13
4.1 Procedure specification principles . 13
4.2 Forwards and backwards compatibility . 14
4.3 Specification notations . 14
5 XnAP services . 14
5.1 XnAP procedure modules . 14
5.2 Parallel transactions . 14
6 Services expected from signalling transport . 14
7 Functions of XnAP . 15
8 XnAP procedures . 15
8.1 Elementary procedures . 15
8.2 Basic mobility procedures . 17
8.2.1 Handover Preparation . 17
8.2.1.1 General . 17
8.2.1.2 Successful Operation . 17
8.2.1.3 Unsuccessful Operation . 20
8.2.1.4 Abnormal Conditions . 20
8.2.2 SN Status Transfer . 20
8.2.2.1 General . 20
8.2.2.2 Successful Operation . 21
8.2.2.3 Unsuccessful Operation . 21
8.2.2.4 Abnormal Conditions . 21
8.2.3 Handover Cancel . 22
8.2.3.1 General . 22
8.2.3.2 Successful Operation . 22
8.2.3.3 Unsuccessful Operation . 22
8.2.3.4 Abnormal Conditions . 22
8.2.4 Retrieve UE Context . 22
8.2.4.1 General . 22
8.2.4.2 Successful Operation . 23
8.2.4.3 Unsuccessful Operation . 23
8.2.4.4 Abnormal Conditions . 24
8.2.5 RAN Paging . 24
8.2.5.1 General . 24
8.2.5.2 Successful operation. 24
8.2.5.3 Unsuccessful Operation . 24
8.2.5.4 Abnormal Condition. 24
8.2.6 XN-U Address Indication . 24
8.2.6.1 General . 24
8.2.6.2 Successful Operation . 25
8.2.6.3 Unsuccessful Operation . 25
8.2.6.4 Abnormal Conditions . 26
ETSI
3GPP TS 38.423 version 15.20.0 Release 15 4 ETSI TS 138 423 V15.20.0 (2024-09)
8.2.7 UE Context Release . 26
8.2.7.1 General . 26
8.2.7.2 Successful Operation . 26
8.2.7.3 Unsuccessful Operation . 27
8.2.7.4 Abnormal Conditions . 27
8.3 Procedures for Dual Connectivity . 28
8.3.1 S-NG-RAN node Addition Preparation . 28
8.3.1.1 General . 28
8.3.1.2 Successful Operation . 28
8.3.1.3 Unsuccessful Operation . 31
8.3.1.4 Abnormal Conditions . 31
8.3.2 S-NG-RAN node Reconfiguration Completion . 32
8.3.2.1 General . 32
8.3.2.2 Successful Operation . 32
8.3.2.3 Abnormal Conditions . 32
8.3.3 M-NG-RAN node initiated S-NG-RAN node Modification Preparation . 33
8.3.3.1 General . 33
8.3.3.2 Successful Operation . 33
8.3.3.3 Unsuccessful Operation . 38
8.3.3.4 Abnormal Conditions . 38
8.3.4 S-NG-RAN node initiated S-NG-RAN node Modification . 39
8.3.4.1 General . 39
8.3.4.2 Successful Operation . 40
8.3.4.3 Unsuccessful Operation . 42
8.3.4.4 Abnormal Conditions . 42
8.3.5 S-NG-RAN node initiated S-NG-RAN node Change . 43
8.3.5.1 General . 43
8.3.5.2 Successful Operation . 43
8.3.5.3 Unsuccessful Operation . 43
8.3.5.4 Abnormal Conditions . 44
8.3.6 M-NG-RAN node initiated S-NG-RAN node Release . 44
8.3.6.1 General . 44
8.3.6.2 Successful Operation . 44
8.3.6.3 Unsuccessful Operation . 45
8.3.6.4 Abnormal Conditions . 45
8.3.7 S-NG-RAN node initiated S-NG-RAN node Release . 45
8.3.7.1 General . 45
8.3.7.2 Successful Operation . 46
8.3.7.3 Unsuccessful Operation . 46
8.3.7.4 Abnormal Conditions . 46
8.3.8 S-NG-RAN node Counter Check . 46
8.3.8.1 General . 46
8.3.8.2 Successful Operation . 47
8.3.8.3 Unsuccessful Operation . 47
8.3.8.4 Abnormal Conditions . 47
8.3.9 RRC Transfer . 47
8.3.9.1 General . 47
8.3.9.2 Successful Operation . 48
8.3.9.3 Unsuccessful Operation . 48
8.3.9.4 Abnormal Conditions . 48
8.3.10 Notification Control Indication . 48
8.3.10.1 General . 48
8.3.10.2 Successful Operation – M-NG-RAN node initiated . 49
8.3.10.3 Successful Operation – S-NG-RAN node initiated . 49
8.3.10.4 Abnormal Conditions . 49
8.3.11 Activity Notification . 49
8.3.11.1 General . 49
8.3.11.2 Successful Operation . 50
8.3.11.3 Abnormal Conditions . 50
8.3.12 E-UTRA – NR Cell Resource Coordination . 50
8.3.12.1 General . 50
8.3.12.2 Successful Operation . 51
ETSI
3GPP TS 38.423 version 15.20.0 Release 15 5 ETSI TS 138 423 V15.20.0 (2024-09)
8.3.13 Secondary RAT Data Usage Report . 52
8.3.13.1 General . 52
8.3.13.2 Successful Operation . 52
8.3.13.3 Unsuccessful Operation . 52
8.3.13.4 Abnormal Conditions . 52
8.4 Global procedures. 52
8.4.1 Xn Setup . 52
8.4.1.1 General . 52
8.4.1.2 Successful Operation . 53
8.4.1.3 Unsuccessful Operation . 54
8.4.1.4 Abnormal Conditions . 54
8.4.2 NG-RAN node Configuration Update . 54
8.4.2.1 General . 54
8.4.2.2 Successful Operation . 55
8.4.2.3 Unsuccessful Operation . 57
8.4.2.4 Abnormal Conditions . 57
8.4.3 Cell Activation . 57
8.4.3.1 General . 57
8.4.3.2 Successful Operation . 57
8.4.3.3 Unsuccessful Operation . 58
8.4.3.4 Abnormal Conditions . 58
8.4.4 Reset . 58
8.4.4.1 General . 58
8.4.4.2 Successful Operation . 59
8.4.4.3 Unsuccessful Operation . 59
8.4.4.4 Abnormal Conditions . 59
8.4.5 Error Indication . 60
8.4.5.1 General . 60
8.4.5.2 Successful Operation . 60
8.4.5.3 Unsuccessful Operation . 60
8.4.5.4 Abnormal Conditions . 60
8.4.6 Xn Removal . 60
8.4.6.1 General . 60
8.4.6.2 Successful Operation . 61
8.4.6.3 Unsuccessful Operation . 61
8.4.6.4 Abnormal Conditions . 61
9 Elements for XnAP Communication . 62
9.0 General . 62
9.1 Message Functional Definition and Content . 62
9.1.1 Messages for Basic Mobility Procedures . 62
9.1.1.1 HANDOVER REQUEST . 62
9.1.1.2 HANDOVER REQUEST ACKNOWLEDGE. 63
9.1.1.3 HANDOVER PREPARATION FAILURE . 64
9.1.1.4 SN STATUS TRANSFER . 64
9.1.1.5 UE CONTEXT RELEASE . 65
9.1.1.6 HANDOVER CANCEL . 65
9.1.1.7 RAN PAGING . 66
9.1.1.8 RETRIEVE UE CONTEXT REQUEST . 66
9.1.1.9 RETRIEVE UE CONTEXT RESPONSE . 68
9.1.1.10 RETRIEVE UE CONTEXT FAILURE . 68
9.1.1.11 XN-U ADDRESS INDICATION . 68
9.1.2 Messages for Dual Connectivity Procedures . 69
9.1.2.1 S-NODE ADDITION REQUEST . 69
9.1.2.2 S-NODE ADDITION REQUEST ACKNOWLEDGE . 72
9.1.2.3 S-NODE ADDITION REQUEST REJECT . 73
9.1.2.4 S-NODE RECONFIGURATION COMPLETE . 74
9.1.2.5 S-NODE MODIFICATION REQUEST . 74
9.1.2.6 S-NODE MODIFICATION REQUEST ACKNOWLEDGE . 77
9.1.2.7 S-NODE MODIFICATION REQUEST REJECT . 80
9.1.2.8 S-NODE MODIFICATION REQUIRED . 80
9.1.2.9 S-NODE MODIFICATION CONFIRM . 82
ETSI
3GPP TS 38.423 version 15.20.0 Release 15 6 ETSI TS 138 423 V15.20.0 (2024-09)
9.1.2.10 S-NODE MODIFICATION REFUSE . 83
9.1.2.11 S-NODE CHANGE REQUIRED . 83
9.1.2.12 S-NODE CHANGE CONFIRM . 84
9.1.2.13 S-NODE CHANGE REFUSE . 85
9.1.2.14 S-NODE RELEASE REQUEST . 85
9.1.2.15 S-NODE RELEASE REQUEST ACKNOWLEDGE . 86
9.1.2.16 S-NODE RELEASE REJECT . 86
9.1.2.17 S-NODE RELEASE REQUIRED . 86
9.1.2.18 S-NODE RELEASE CONFIRM . 87
9.1.2.19 S-NODE COUNTER CHECK REQUEST . 87
9.1.2.20 RRC TRANSFER . 88
9.1.2.21 NOTIFICATION CONTROL INDICATION . 89
9.1.2.22 ACTIVITY NOTIFICATION . 89
9.1.2.23 E-UTRA – NR CELL RESOURCE COORDINATION REQUEST. 90
9.1.2.24 E-UTRA – NR CELL RESOURCE COORDINATION RESPONSE . 91
9.1.2.25 SECONDARY RAT DATA USAGE REPORT . 92
9.1.3 Messages for Global Procedures . 93
9.1.3.1 XN SETUP REQUEST . 93
9.1.3.2 XN SETUP RESPONSE . 94
9.1.3.3 XN SETUP FAILURE . 94
9.1.3.4 NG-RAN NODE CONFIGURATION UPDATE . 95
9.1.3.5 NG-RAN NODE CONFIGURATION UPDATE ACKNOWLEDGE . 96
9.1.3.6 NG-RAN NODE CONFIGURATION UPDATE FAILURE . 97
9.1.3.7 CELL ACTIVATION REQUEST . 97
9.1.3.8 CELL ACTIVATION RESPONSE . 98
9.1.3.9 CELL ACTIVATION FAILURE . 98
9.1.3.10 RESET REQUEST . 98
9.1.3.11 RESET RESPONSE. 99
9.1.3.12 ERROR INDICATION . 100
9.1.3.13 XN REMOVAL REQUEST . 100
9.1.3.14 XN REMOVAL RESPONSE . 100
9.1.3.15 XN REMOVAL FAILURE . 101
9.2 Information Element definitions . 101
9.2.0 General . 101
9.2.1 Container and List IE definitions . 101
9.2.1.1 PDU Session Resources To Be Setup List . 101
9.2.1.2 PDU Session Resources Admitted List . 102
9.2.1.3 PDU Session Resources Not Admitted List . 103
9.2.1.4 QoS Flow List with Cause . 103
9.2.1.4a QoS Flow List . 104
9.2.1.5 PDU Session Resource Setup Info – SN terminated . 104
9.2.1.6 PDU Session Resource Setup Response Info – SN terminated . 105
9.2.1.7 PDU Session Resource Setup Info – MN terminated . 106
9.2.1.8 PDU Session Resource Setup Response Info – MN terminated . 107
9.2.1.9 PDU Session Resource Modification Info – SN terminated . 108
9.2.1.10 PDU Session Resource Modification Response Info – SN terminated . 110
9.2.1.11 PDU Session Resource Modification Info – MN terminated . 112
9.2.1.12 PDU Session Resource Modification Response Info – MN terminated . 113
9.2.1.13 UE Context Information Retrieve UE Context Response . 114
9.2.1.14 DRBs Subject To Status Transfer List . 115
9.2.1.15 DRB to QoS Flow Mapping List. 117
9.2.1.16 Data Forwarding Info from target NG-RAN node . 117
9.2.1.17 Data Forwarding and Offloading Info from source NG-RAN node . 118
9.2.1.18 PDU Session Resource Change Required Info – SN terminated . 118
9.2.1.19 PDU Session Resource Change Confirm Info – SN terminated . 119
9.2.1.20 PDU Session Resource Modification Required Info – SN terminated . 119
9.2.1.21 PDU Session Resource Modification Confirm Info – SN terminated . 121
9.2.1.22 PDU Session Resource Modification Required Info – MN terminated. 122
9.2.1.23 PDU Session Resource Modification Confirm Info – MN terminated . 123
9.2.1.24 PDU Session List with data forwarding request info . 123
9.2.1.25 PDU Session List with data forwarding info from the target node . 123
9.2.1.26 PDU Session List with Cause. 124
ETSI
3GPP TS 38.423 version 15.20.0 Release 15 7 ETSI TS 138 423 V15.20.0 (2024-09)
9.2.1.27 PDU Session List . 124
9.2.1.28 DRB List with Cause . 124
9.2.1.29 DRB List . 124
9.2.1.30 PDU Session Resource Setup Complete Info – SN terminated . 125
9.2.1.31 Secondary Data Forwarding Info from target NG-RAN node List . 125
9.2.1.32 Additional UL NG-U UP TNL Information at UPF List . 125
9.2.2 NG-RAN Node and Cell Configuration related IE definitions . 126
9.2.2.1 Global gNB ID . 126
9.2.2.2 Global ng-eNB ID . 126
9.2.2.3 Global NG-RAN Node ID . 126
9.2.2.4 PLMN Identity . 127
9.2.2.5 TAC. 127
9.2.2.6 RAN Area Code . 127
9.2.2.7 NR CGI .
...