ETSI TS 136 423 V15.7.0 (2019-10)

ETSI TS 136 423 V15.7.0 (2019-10)






TECHNICAL SPECIFICATION
LTE;
Evolved Universal Terrestrial
Radio Access Network (E-UTRAN);
X2 Application Protocol (X2AP)
(3GPP TS 36.423 version 15.7.0 Release 15)

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3GPP TS 36.423 version 15.7.0 Release 15 1 ETSI TS 136 423 V15.7.0 (2019-10)



Reference
RTS/TSGR-0336423vf70
Keywords
LTE
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3GPP TS 36.423 version 15.7.0 Release 15 2 ETSI TS 136 423 V15.7.0 (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.
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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

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3GPP TS 36.423 version 15.7.0 Release 15 3 ETSI TS 136 423 V15.7.0 (2019-10)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 12
1 Scope . 13
2 References . 13
3 Definitions, symbols and abbreviations . 15
3.1 Definitions . 15
3.2 Symbols . 15
3.3 Abbreviations . 15
4 General . 16
4.1 Procedure specification principles . 16
4.2 Forwards and backwards compatibility . 17
4.3 Specification notations . 17
5 X2AP services . 17
5.1 X2AP procedure modules . 17
5.2 Parallel transactions . 17
6 Services expected from signalling transport . 18
7 Functions of X2AP . 18
8 X2AP procedures . 19
8.1 Elementary procedures . 19
8.2 Basic mobility procedures . 22
8.2.1 Handover Preparation . 22
8.2.1.1 General . 22
8.2.1.2 Successful Operation . 23
8.2.1.3 Unsuccessful Operation . 25
8.2.1.4 Abnormal Conditions . 26
8.2.2 SN Status Transfer . 26
8.2.2.1 General . 26
8.2.2.2 Successful Operation . 27
8.2.2.3 Abnormal Conditions . 28
8.2.3 UE Context Release . 28
8.2.3.1 General . 28
8.2.3.2 Successful Operation . 29
8.2.3.3 Unsuccessful Operation . 30
8.2.3.4 Abnormal Conditions . 30
8.2.4 Handover Cancel . 30
8.2.4.1 General . 30
8.2.4.2 Successful Operation . 31
8.2.4.3 Unsuccessful Operation . 31
8.2.4.4 Abnormal Conditions . 31
8.3 Global Procedures . 31
8.3.1 Load Indication . 31
8.3.1.1 General . 31
8.3.1.2 Successful Operation . 31
8.3.1.3 Unsuccessful Operation . 33
8.3.1.4 Abnormal Conditions . 33
8.3.2 Error Indication . 33
8.3.2.1 General . 33
8.3.2.2 Successful Operation . 33
8.3.2.3 Unsuccessful Operation . 34
ETSI

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3GPP TS 36.423 version 15.7.0 Release 15 4 ETSI TS 136 423 V15.7.0 (2019-10)
8.3.2.4 Abnormal Conditions . 34
8.3.3 X2 Setup . 34
8.3.3.1 General . 34
8.3.3.2 Successful Operation . 35
8.3.3.3 Unsuccessful Operation . 36
8.3.3.4 Abnormal Conditions . 36
8.3.4 Reset . 36
8.3.4.1 General . 36
8.3.4.2 Successful Operation . 37
8.3.4.3 Unsuccessful Operation . 37
8.3.4.4 Abnormal Conditions . 37
8.3.5 eNB Configuration Update . 38
8.3.5.1 General . 38
8.3.5.2 Successful Operation . 38
8.3.5.3 Unsuccessful Operation . 40
8.3.5.4 Abnormal Conditions . 40
8.3.6 Resource Status Reporting Initiation . 40
8.3.6.1 General . 40
8.3.6.2 Successful Operation . 40
8.3.6.3 Unsuccessful Operation . 42
8.3.6.4 Abnormal Conditions . 42
8.3.7 Resource Status Reporting . 43
8.3.7.1 General . 43
8.3.7.2 Successful Operation . 43
8.3.7.3 Unsuccessful Operation . 43
8.3.7.4 Abnormal Conditions . 43
8.3.8 Mobility Settings Change . 43
8.3.8.1 General . 43
8.3.8.2 Successful Operation . 44
8.3.8.3 Unsuccessful Operation . 44
8.3.8.4 Abnormal Conditions . 44
8.3.9 Radio Link Failure Indication . 44
8.3.9.1 General . 44
8.3.9.2 Successful Operation . 45
8.3.9.3 Unsuccessful Operation . 45
8.3.9.4 Abnormal Conditions . 45
8.3.10 Handover Report . 45
8.3.10.1 General . 45
8.3.10.2 Successful Operation . 46
8.3.10.3 Unsuccessful Operation . 46
8.3.10.4 Abnormal Conditions . 46
8.3.11 Cell Activation . 46
8.3.11.1 General . 46
8.3.11.2 Successful Operation . 47
8.3.11.3 Unsuccessful Operation . 47
8.3.11.4 Abnormal Conditions . 47
8.3.12 X2 Removal . 47
8.3.12.1 General . 47
8.3.12.2 Successful Operation . 48
8.3.12.3 Unsuccessful Operation . 48
8.3.12.4 Abnormal Conditions . 48
8.3.13 Retrieve UE Context . 48
8.3.13.1 General . 48
8.3.13.2 Successful Operation . 49
8.3.13.3 Unsuccessful Operation . 50
8.3.13.4 Abnormal Conditions . 50
8.3.14 EN-DC X2 Removal . 50
8.3.14.1 General . 50
8.3.14.2 Successful Operation . 50
8.3.14.3 Unsuccessful Operation . 51
8.3.14.4 Abnormal Conditions . 52
8.3.15 Data Forwarding Address Indication . 52
ETSI

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3GPP TS 36.423 version 15.7.0 Release 15 5 ETSI TS 136 423 V15.7.0 (2019-10)
8.3.15.1 General . 52
8.3.15.2 Successful Operation . 52
8.3.15.3 Unsuccessful Operation . 52
8.3.15.4 Abnormal Conditions . 53
8.4 X2 Release. 53
8.4.1 General . 53
8.4.2 Successful Operation . 53
8.4.3 Unsuccessful Operation . 53
8.4.4 Abnormal Condition . 53
8.5 X2AP Message Transfer . 53
8.5.1 General . 53
8.5.2 Successful Operation . 54
8.5.3 Unsuccessful Operation . 54
8.5.4 Abnormal Condition . 54
8.6 Procedures for Dual Connectivity . 54
8.6.1 SeNB Addition Preparation . 54
8.6.1.1 General . 54
8.6.1.2 Successful Operation . 55
8.6.1.3 Unsuccessful Operation . 56
8.6.1.4 Abnormal Conditions . 56
8.6.2 SeNB Reconfiguration Completion . 57
8.6.2.1 General . 57
8.6.2.2 Successful Operation . 57
8.6.2.3 Abnormal Conditions . 58
8.6.3 MeNB initiated SeNB Modification Preparation . 58
8.6.3.1 General . 58
8.6.3.2 Successful Operation . 58
8.6.3.3 Unsuccessful Operation . 60
8.6.3.4 Abnormal Conditions . 60
8.6.4 SeNB initiated SeNB Modification . 61
8.6.4.1 General . 61
8.6.4.2 Successful Operation . 61
8.6.4.3 Unsuccessful Operation . 62
8.6.4.4 Abnormal Conditions . 62
8.6.5 MeNB initiated SeNB Release. 63
8.6.5.1 General . 63
8.6.5.2 Successful Operation . 63
8.6.5.3 Unsuccessful Operation . 63
8.6.5.4 Abnormal Conditions . 64
8.6.6 SeNB initiated SeNB Release . 64
8.6.6.1 General . 64
8.6.6.2 Successful Operation .
...