ETSI TS 136 423 V14.8.0 (2019-10)

TECHNICAL SPECIFICATION
LTE;
Evolved Universal Terrestrial
Radio Access Network (E-UTRAN);
X2 Application Protocol (X2AP)
(3GPP TS 36.423 version 14.8.0 Release 14)

3GPP TS 36.423 version 14.8.0 Release 14 1 ETSI TS 136 423 V14.8.0 (2019-10)

Reference
RTS/TSGR-0336423ve80
Keywords
LTE
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ETSI
3GPP TS 36.423 version 14.8.0 Release 14 2 ETSI TS 136 423 V14.8.0 (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
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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
3GPP TS 36.423 version 14.8.0 Release 14 3 ETSI TS 136 423 V14.8.0 (2019-10)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 9
1 Scope . 10
2 References . 10
3 Definitions, symbols and abbreviations . 11
3.1 Definitions . 11
3.2 Symbols . 12
3.3 Abbreviations . 12
4 General . 13
4.1 Procedure specification principles . 13
4.2 Forwards and backwards compatibility . 13
4.3 Specification notations . 13
5 X2AP services . 13
5.1 X2AP procedure modules . 14
5.2 Parallel transactions . 14
6 Services expected from signalling transport . 14
7 Functions of X2AP . 14
8 X2AP 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 . 19
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 Abnormal Conditions . 21
8.2.3 UE Context Release . 21
8.2.3.1 General . 21
8.2.3.2 Successful Operation . 22
8.2.3.3 Unsuccessful Operation . 23
8.2.3.4 Abnormal Conditions . 23
8.2.4 Handover Cancel . 23
8.2.4.1 General . 23
8.2.4.2 Successful Operation . 23
8.2.4.3 Unsuccessful Operation . 23
8.2.4.4 Abnormal Conditions . 23
8.3 Global Procedures . 24
8.3.1 Load Indication . 24
8.3.1.1 General . 24
8.3.1.2 Successful Operation . 24
8.3.1.3 Unsuccessful Operation . 25
8.3.1.4 Abnormal Conditions . 25
8.3.2 Error Indication . 25
8.3.2.1 General . 25
8.3.2.2 Successful Operation . 26
8.3.2.3 Unsuccessful Operation . 26
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8.3.2.4 Abnormal Conditions . 26
8.3.3 X2 Setup . 26
8.3.3.1 General . 26
8.3.3.2 Successful Operation . 26
8.3.3.3 Unsuccessful Operation . 28
8.3.3.4 Abnormal Conditions . 28
8.3.4 Reset . 28
8.3.4.1 General . 28
8.3.4.2 Successful Operation . 29
8.3.4.3 Unsuccessful Operation . 29
8.3.4.4 Abnormal Conditions . 29
8.3.5 eNB Configuration Update . 29
8.3.5.1 General . 29
8.3.5.2 Successful Operation . 29
8.3.5.3 Unsuccessful Operation . 31
8.3.5.4 Abnormal Conditions . 32
8.3.6 Resource Status Reporting Initiation . 32
8.3.6.1 General . 32
8.3.6.2 Successful Operation . 32
8.3.6.3 Unsuccessful Operation . 33
8.3.6.4 Abnormal Conditions . 34
8.3.7 Resource Status Reporting . 34
8.3.7.1 General . 34
8.3.7.2 Successful Operation . 35
8.3.7.3 Unsuccessful Operation . 35
8.3.7.4 Abnormal Conditions . 35
8.3.8 Mobility Settings Change . 35
8.3.8.1 General . 35
8.3.8.2 Successful Operation . 36
8.3.8.3 Unsuccessful Operation . 36
8.3.8.4 Abnormal Conditions . 36
8.3.9 Radio Link Failure Indication . 36
8.3.9.1 General . 36
8.3.9.2 Successful Operation . 37
8.3.9.3 Unsuccessful Operation . 37
8.3.9.4 Abnormal Conditions . 37
8.3.10 Handover Report . 37
8.3.10.1 General . 37
8.3.10.2 Successful Operation . 38
8.3.10.3 Unsuccessful Operation . 38
8.3.10.4 Abnormal Conditions . 38
8.3.11 Cell Activation . 38
8.3.11.1 General . 38
8.3.11.2 Successful Operation . 39
8.3.11.3 Unsuccessful Operation . 39
8.3.11.4 Abnormal Conditions . 39
8.3.12 X2 Removal . 39
8.3.12.1 General . 39
8.3.12.2 Successful Operation . 40
8.3.12.3 Unsuccessful Operation . 40
8.3.12.4 Abnormal Conditions . 40
8.3.13 Retrieve UE Context . 40
8.3.13.1 General . 40
8.3.13.2 Successful Operation . 41
8.3.13.3 Unsuccessful Operation . 42
8.3.13.4 Abnormal Conditions . 42
8.4 X2 Release. 42
8.4.1 General . 42
8.4.2 Successful Operation . 42
8.4.3 Unsuccessful Operation . 42
8.4.4 Abnormal Condition . 42
8.5 X2AP Message Transfer . 43
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8.5.1 General . 43
8.5.2 Successful Operation . 43
8.5.3 Unsuccessful Operation . 43
8.5.4 Abnormal Condition . 43
8.6 Procedures for Dual Connectivity . 43
8.6.1 SeNB Addition Preparation . 43
8.6.1.1 General . 43
8.6.1.2 Successful Operation . 44
8.6.1.3 Unsuccessful Operation . 45
8.6.1.4 Abnormal Conditions . 45
8.6.2 SeNB Reconfiguration Completion . 46
8.6.2.1 General . 46
8.6.2.2 Successful Operation . 46
8.6.2.3 Abnormal Conditions . 46
8.6.3 MeNB initiated SeNB Modification Preparation . 47
8.6.3.1 General . 47
8.6.3.2 Successful Operation . 47
8.6.3.3 Unsuccessful Operation . 49
8.6.3.4 Abnormal Conditions . 49
8.6.4 SeNB initiated SeNB Modification . 50
8.6.4.1 General . 50
8.6.4.2 Successful Operation . 50
8.6.4.3 Unsuccessful Operation . 51
8.6.4.4 Abnormal Conditions . 51
8.6.5 MeNB initiated SeNB Release. 52
8.6.5.1 General . 52
8.6.5.2 Successful Operation . 52
8.6.5.3 Unsuccessful Operation . 52
8.6.5.4 Abnormal Conditions . 52
8.6.6 SeNB initiated SeNB Release . 53
8.6.6.1 General . 53
8.6.6.2 Successful Operation . 53
8.6.6.3 Unsuccessful Operation . 53
8.6.6.4 Abnormal Conditions . 53
8.6.7 SeNB Counter Check . 53
8.6.7.1 General . 53
8.6.7.2 Successful Operation . 54
8.6.7.3 Unsuccessful Operation . 54
8.6.7.4 Abnormal Conditions . 54
9 Elements for X2AP Communication . 54
9.0 General . 54
9.1 Message Functional Definition and Content . 54
9.1.1 Messages for Basic Mobility Procedures . 54
9.1.1.1 HANDOVER REQUEST . 54
9.1.1.2 HANDOVER REQUEST ACKNOWLEDGE. 56
9.1.1.3 HANDOVER PREPARATION FAILURE . 58
9.1.1.4 SN STATUS TRANSFER . 58
9.1.1.5 UE CONTEXT RELEASE . 60
9.1.1.6 HANDOVER CANCEL . 61
9.1.2 Messages for global procedures . 61
9.1.2.1 LOAD INFORMATION . 61
9.1.2.2 ERROR INDICATION . 62
9.1.2.3 X2 SETUP REQUEST . 63
9.1.2.4 X2 SETUP RESPONSE . 64
9.1.2.5 X2 SETUP FAILURE . 65
9.1.2.6 RESET REQUEST . 66
9.1.2.7 RESET RESPONSE. 66
9.1.2.8 ENB CONFIGURATION UPDATE . 66
9.1.2.9 ENB CONFIGURATION UPDATE ACKNOWLEDGE . 69
9.1.2.10 ENB CONFIGURATION UPDATE FAILURE. 69
9.1.2.11 RESOURCE STATUS REQUEST . 69
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9.1.2.12 RESOURCE STATUS RESPONSE . 71
9.1.2.13 RESOURCE STATUS FAILURE . 73
9.1.2.14 RESOURCE STATUS UPDATE . 74
9.1.2.15 MOBILITY CHANGE REQUEST . 74
9.1.2.16 MOBILITY CHANGE ACKNOWLEDGE . 75
9.1.2.17 MOBILITY CHANGE FAILURE . 75
9.1.2.18 RLF INDICATION . 75
9.1.2.19 HANDOVER REPORT . 76
9.1.2.20 CELL ACTIVATION REQUEST . 77
9.1.2.21 CELL ACTIVATION RESPONSE . 78
9.1.2.22 CELL ACTIVATION FAILURE . 78
9.1.2.23 X2 RELEASE . 78
9.1.2.24 X2AP MESSAGE TRANSFER . 78
9.1.2.25 X2 REMOVAL REQUEST . 79
9.1.2.26 X2 REMOVAL RESPONSE . 79
9.1.2.27 X2 REMOVAL FAILURE . 79
9.1.2.28 RETRIEVE UE CONTEXT REQUEST . 79
9.1.2.29 RETRIEVE UE CONTEXT RESPONSE . 80
9.1.2.30 RETRIEVE UE CONTEXT FAILURE . 82
9.1.3 Messages for Dual Connectivity Procedures . 82
9.1.3.1 SENB ADDITION REQUEST . 82
9.1.3.2 SENB ADDITION REQUEST ACKNOWLEDGE . 84
9.1.3.3 SENB ADDITION REQUEST REJECT . 86
9.1.3.4 SENB RECONFIGURATION COMPLETE . 86
9.1.3.5 SENB MODIFICATION REQUEST . 87
9.1.3.6 SENB MODIFICATION REQUEST ACKNOWLEDGE . 89
9.1.3.7 SENB MODIFICATION REQUEST REJECT . 91
9.1.3.8 SENB MODIFICATION REQUIRED . 92
9.1.3.9 SENB MODIFICATION CONFIRM . 92
9.1.3.10 SENB MODIFICATION REFUSE . 93
9.1.3.11 SENB RELEASE REQUEST . 94
9.1.3.12 SENB RELEASE REQUIRED . 94
9.1.3.13 SENB RELEASE CONFIRM . 95
9.1.3.14 SENB COUNTER CHECK REQUEST . 96
9.2 Information Element definitions . 97
9.2.0 General . 97
9.2.1 GTP Tunnel Endpoint . 97
9.2.2 Trace Activation . 98
9.2.3 Handover Restriction List . 98
9.2.4 PLMN Identity . 99
9.2.5 DL Forwarding . 100
9.2.6 Cause . 100
9.2.7 Criticality Diagnostics . 105
9.2.8 Served Cell Information . 106
9.2.9 E-RAB Level QoS Parameters. 109
9.2.10 GBR QoS Information . 110
9.2.11 Bit Rate . 110
9.2.12 UE Aggregate Maximum Bit Rate . 111
9.2.13 Message Type . 111
9.2.14 ECGI . 111
9.2.15 COUNT Value . 111
9.2.16 GUMMEI . 112
9.2.17 UL Interference Overload Indication . 112
9.2.18 UL High Interference Indication . 112
9.2.19 Relative Narrowband Tx Power (RNTP) . 112
9.2.20 GU Group Id . 115
9.2.21 Location Reporting Information . 115
9.2.22 Global eNB ID . 115
9.2.23 E-RAB ID . 115
9.2.24 eNB UE X2AP ID . 116
9.2.25 Subscriber Profile ID for RAT/Frequency priority . 116
9.2.26 EARFCN . 116
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9.2.27 Transmission Bandwidth . 116
9.2.28 E-RAB List . 116
9.2.29 UE Security Capabilities . 117
9.2.30 AS Security Information . 117
9.2.31 Allocation and Retention Priority . 118
9.2.32 Time To Wait . 118
9.2.33 SRVCC Operation Possible . 119
9.2.34 Hardware Load Indicator . 119
9.2.35 S1 TNL Load Indicator . 119
9.2.36 Load Indicator . 119
9.2.37 Radio Resource Status . 119
9.2.38 UE History Information . 119
9.2.39 Last Visited Cell Information . 120
9.2.40 Last Visited E-UTRAN Cell Information . 120
9.2.41 Last Visited GERAN Cell Information . 121
9.2.42 Cell Type . 121
9.2.43 Number of Antenna Ports .
...