Foreword1 Scope2 References3 Definitions, symbols and abbreviations4 General5 XnAP services6 Services expected from signalling transport7 Functions of XnAP8 XnAP procedures8.1 Elementary procedures8.2 Basic mobility procedures8.3 Procedures for Dual Connectivity8.3.1 S-NG-RAN node Addition Preparation8.3.2 S-NG-RAN node Reconfiguration Completion8.3.3 M-NG-RAN node initiated S-NG-RAN node Modification Preparation8.3.4 S-NG-RAN node initiated S-NG-RAN node Modification8.3.5 S-NG-RAN node initiated S-NG-RAN node Change8.3.6 M-NG-RAN node initiated S-NG-RAN node Release8.3.7 S-NG-RAN node initiated S-NG-RAN node Release8.3.8 S-NG-RAN node Counter Check8.3.9 RRC Transfer8.3.10 Notification Control Indication8.3.11 Activity Notification8.3.12 E-UTRA – NR Cell Resource Coordination8.3.13 Secondary RAT Data Usage Report8.3.14 Trace Start8.3.15 Deactivate Trace8.3.16 Cell Traffic Trace8.3.17 SCG Failure Information Report8.3.18 SCG Failure Transfer8.3.19 Conditional PSCell Change Cancel8.4 Global procedures8.5 IAB Procedures9 Elements for XnAP Communication9.0 General9.1 Message Functional Definition and Content9.1.1 Messages for Basic Mobility Procedures9.1.2 Messages for Dual Connectivity Procedures9.1.3 Messages for Global Procedures9.1.4 Messages for IAB Procedures9.2 Information Element definitions9.2.0 General9.2.1 Container and List IE definitions9.2.2 NG-RAN Node and Cell Configuration related IE definitions9.2.3 General IE definitions9.3 Message and Information Element Abstract Syntax (with ASN.1)9.3.1 General9.3.2 Usage of Private Message Mechanism for Non-standard Use9.3.3 Elementary Procedure Definitions9.3.4 PDU Definitions9.3.5 Information Element definitions9.3.6 Common definitions9.3.7 Constant definitions9.3.8 Container definitions9.4 Message transfer syntax9.5 Timers10 Handling of unknown, unforeseen and erroneous protocol data 7 Functions of XnAP 38.4233GPPNG-RANRelease 17TSXn Application Protocol (XnAP) Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM The functions of XnAP are specified in TS 38.420 [3].